hull speed of a catamaran

How Fast Do Catamarans Go? 5 Examples (With Pictures)

A catamaran is generally more balanced on the water and can be faster than a multi-hull vessel.

Unless you compare them to foiling monohulls like the new America’s Cup boats that sail at over 50 knots, they are not recreational vessels.

In this article, we will look at how fast each type of catamaran will go.

Table of Contents

Here are the numbers before we dive into the details:


Sport Catamarans	30 knots
Cruising Catamarans	15 knots
Racing Catamarans	45 knots
Power Cruising Catamarans	70 knots
Swath Catamarans	30 knots

Average Speed For Sailing Catamarans

Catamarans can vary in size from 14 ft to over 100 ft. Catamarans can come in a wide variety of design types.

Sailing Catamarans have been attempting to make advancements over their mono-hulled counterparts.

These advancements include:

Foils that assist with lifting the vessel out of the water.
Stability advancements.
Racers that can maintain their speed while out in the ocean.

3 Different Types of Sailing Catamarans:

1) sport catamarans.

One type of sailing catamaran is a sport catamaran, which is otherwise known as recreational. These are typically supposed to have a small crew and launch and land on beaches.

Sport catamarans do not normally have living quarters and are ideal for day trips. Resorts or other rental services often use these.

These can also be used for racing.

Sport vessels have been known to travel over 30 knots but can speed over 40 knots in the proper conditions.

2) Cruising Catamarans

Another type of sailing catamaran is a cruising catamaran. These often come with complete living accommodations, so they sacrifice speed over their sportier counterparts.

They can average between 9 and 10 knots, depending on the conditions. The top speed is typically around 15 knots.

It would be best if you were careful with catamarans that have living quarters. The more you weigh it down, the less speed you will have.

3) Racing Catamarans

The final type of sailing catamaran is an ocean racing catamaran.

These boats are large and can reach over 100 feet in length.

The top speed of this type of catamaran is around 45 knots.

Because of the prize money for entering these in races, much research goes into their advancement.

Average Speed Of Power Catamarans

Catamarans with power motors fill a different type of boating category.

These are commonly used when speed and smoothness are favored over space or capacity.

Because of their stability, catamarans are good vessels for combating seasickness as well as transportation. We have a separate article here with all you should know about catamarans and (how to overcome) seasickness .

On a commercial level, these can be used for ferries for both people and vehicles. They are used for short term travel, often to or from islands.

Like sailing catamarans, there are a few types of power catamarans.

1) Power Cruising Catamarans

Similar to sailing cruising catamarans, they also have power cruising catamarans. These also have living quarters and are stable while out on the water. The speed of these vessels highly depends on the motors equipped and the size of the boat itself.

Like passenger transport or ferries, catamarans have a high speed of about 40 to 70 miles per hour.

These are made to travel at great speeds to allow their commuters the shortest possible ride to their destination.

The military also utilizes power catamarans. They use power catamarans to transport military cargo. These ships are ideal because of their speed, holding capacity, and ability to venture into shallow ports.

2) Swath Catamarans

They also have small-waterplane-area twin-hull vessels. These are called SWATHs.

These differ from the average catamaran because they also have submarine-like hulls that stay completely under the water.

Due to the hulls being submerged, they are not normally affected by waves. These are used most often in the ocean as research vessels. They can also be used for certain types of yachts. Because of their stability, they are good vessels for furniture that will not require as much securing.

These often travel between 20 and 30 knots.

Some catamarans are designed for wave piercing. These are made to pierce through waves rather than sail over them, causing them to be faster. These can be used as passenger ferries, yachts, and military vessels as well.

3) Whitewater Catamarans

There are also recreational catamarans made for whitewater travel. These are sometimes called “cata-rafts.”

They are made using two inflatable hulls connected with a scaffold. These are lightweight and perfect for whitewater sports.

They are even able to be packed away in a backpack. They can take up to 20 minutes to assemble, including inflation.

They have high speeds on white water rivers and can be most compared to a canoe, kayak, whitewater raft, or other white water vessels.

Performance Characteristics Of Catamarans

Catamarans require four times the power to double their speed. A mono-hull vessel, however, would require eight times the power to double their speed.

This is because a Catamaran has less resistance in the water.

This is also good for conserving and using less energy.

Catamarans are also more stable in the water. This stability is effective at resisting heeling or capsizing. A multi-hull vessel would require four times the force to capsize as a similar-sized mono-hull vessel.

The general sailing in a catamaran is smoother and allows for activities that are not always possible on a mono-hull sailboat.

Are Catamarans Faster than Mono-Hull Vessels?

Because catamarans have less water resistance, they are generally faster than mono-hull vessels.

This is because their hulls are smaller, which means they have a smaller bow wave to fight.

A bow wave is a wave created by the displacement of water by the bow of a ship. After a certain speed, a boat has to start hauling itself over its own bow wave.

The larger hull a ship has, the larger its bow wave will be and the more power required to fight it.

Catamarans have two small and narrow hulls, so they do not have much of an issue with their bow wave. This is one reason they are usually faster than a similar-sized mono-hull vessel.

Catamarans can be between 20-30 percent faster than their monohull counterparts.

Issues with catamarans over mono-hulls are that they can take more time to turn.

How Is The Speed Measured?

Boats commonly measure speed using GPS tracking devices to measure distance traveled. Speed while sailing is measured in knots. A knot is one nautical mile per hour, which equals about 1.15 miles per hour.

How Fast Are Catamarans Compared To Other Boat Types?

Sailing catamarans typically average about 10 knots.
Pontoon boats average about 20 mph.
A powerboat cruiser can average anywhere between 30 and 50 mph.
Cigarette boats can even reach close to 90 mph in the proper conditions.
Sailboats average between 6 and 12 mph depending on wind conditions. This includes mono-hull between 6 to 8 mph and catamarans and trimarans between 9 and 10mph

Two different factors can determine the speed of sailing ships:

1) The hull type as listed above.

Different hulls rest in the water more or less than other types. The less of the hull that is underwater, the faster it can go.

This is because the less of the hull in the water, the less drag created while sailing.

2) The length of the boat

The longer the boat, the faster it can go. Every boat has a maximum hull speed that cannot be exceeded unless the boat can plane on the water’s surface or be lifted on hydrofoils. For most boats, the longer the boat, the higher the maximum hull speed is.

Speed Vs. Comfort Considerations For Catamarans

If you are looking for a catamaran, you have a lot of options.

You can choose to prioritize speed or comfort.

After deciding to purchase a catamaran, the type of catamaran you should look at depends on where and what you are using it for.

You will want to make sure that you look at what type of water you will be traveling in, how many people you are traveling with on average, and what type of speed you hope to achieve.

One thing you will want to keep in mind before the purchase of a catamaran is storage. If you intend to store your boat in a marina, you are often charged for two slips due to the beam, or width, of a catamaran versus the standard mono-hull vessel.

Catamarans can be beneficial for those who get seasick because they offer a steadier ride and the ability to have more open air space. Because the living quarters are not inside the hull and under the water’s surface, you have more windows and visibility.

Both sailing and power catamarans are viable options. Also, sailing catamarans can come with back-up power engines for low winds or situations such as docking in a marina.

Catamarans that have twin engines can offer more control and precision than those on a mono-hull vessel. This is good for tight and busy areas or navigating marinas.

Overall, there are plenty of options for you, and they offer many benefits over their mono-hull counterparts.

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The 8 Fastest Cruising Catamarans (With Speedchart)

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Cruising catamarans are some of the most comfortable boats to roam the water, making them fantastic for both long-term voyages and short-term vacations. Still, cruising catamarans can be great racing boats, but just how fast can they go?

Some of the fastest cruising catamarans include the Gunboat 68 (35 knots), Outremer 45 (25 knots), ORC50 (25 knots), FastCat 435 (20 knots), TS 42 (35 knots), and Lagoon 440 (20 knots). Yet, there are many more cats that can reach 35 knots safely.

If you are interested in knowing about the fastest cruising catamarans, I have you covered. I will be discussing some of the most popular, fastest cruising catamarans and the features that make them so excellent for sailors in need of speed. You will learn more about each catamaran’s speed and amenities, and I will let you know a trick or two to maximize your speed under sail.

CATAMARAN	SPEED (Knots)
Gunboat 68	35+
TS 42	35
Outremer 45	25
ORC 50	25
FastCat 435	20
Lagoon 440	20
Privilege Signature 510 (For reference)	13
Fountaine Pajot Astréa 42 (For reference)	10

How Fast Are Cruising Catamarans?

On average, cruising catamarans can reach top speeds of 15 knots , around 17.3 mph (27.84 kph). However, some exceptional, racing-designed cruising catamarans can reach up to 30+ knots in the right wind conditions.

When you want to better understand catamaran hull characteristics, I suggest the book Catamarans a Complete Guide (amazon link) by the president of Aeroyacht catamarans and that you check out my article Why catamarans capsize .

Factors That Impact Speed

Weight & size.

When you consider a catamaran’s speed, you will need to keep in mind the boat’s weight and narrowness. A vessel that can travel at 15 knots will still move slower if the boat is heavy or has a wide, extensive hull. When increasing the total weight of the boat, the boat “sits” lower in the water, thus increasing water drag and reducing speed.

Why trimarans are faster than catamarans!

Now that we know how weight impacts sailing characteristics, it follows that; if you are planning on racing your catamaran, you should remove as much luggage or extra gear as possible. Eliminating as much weight as possible will help you travel at your cat’s maximum speed .

Narrow Hulls

The hydrodynamics of the ship will heavily affect your speed. Narrower boats can chop through the water with less effort, making slender ships with pointed hulls far faster than wide vessels. So if you are looking for the fastest one available, you should look for a slender hull.

Slim hulls vs. space is a common tradeoff for catamarans optimized for family sailing .

Wind will also affect your ship’s speed, so do not expect your cruising catamaran to reach the maximum speed without heavy wind. Generally, cruising catamarans have two large sails (at least) to power them through the water, and some are so efficient that they can travel even faster than the wind.

Although a strong wind is needed to energize the sails and move the boat, too much wind will instead make the sails less efficient, and maximum speed is most often attained at lower wind speeds but with flat water.

Light Weight Materials

Faster cruising catamarans are often made from carbon fiber materials and fiberglass to keep the weight down. If you are looking for the quickest catamaran that you can find, you should note the materials that the ship is made out of and try to get one that is primarily made from carbon, glass, and resin materials.

While you are looking for the perfect catamaran for you, you should keep in mind what you NEED and what is NICE with your ship. Usually, this decision is between size and speed, but some of these excellent vessels have both.

Lightweight materials are usually costly; for example, a carbon fiber mast will probably cost you +$20 000, depending on the cat’s size.

I have written a buyer’s guide that explains the concept of NEED vs. NICE , which will make choosing the right boat faster and more accurate.

Gunboat 68 (+35Kts)

Gunboat 68 is a cruising catamaran designed to reach the highest speeds possible. Made by Gunboat, the ship uses Grand-Prix racing boats’ designs to develop the speediest cruising catamaran on the market.

Gunboat 68 is made entirely from carbon composites, which keeps the ship lightweight and fast. Gunboat 68 is the perfect catamaran for anyone who wants to reach the highest speeds possible while maintaining control of the vessel and not bouncing around too much.

Gunboat 68 has comfortable, spacious living quarters, though it also has a spacious deck with luxurious seating. Indeed, this cat has it all, making it one of the best cruising catamarans for racers and casual sailors. The design maximizes all of the living spaces and uses lightweight materials to add elegance and luxury to a speedy racing catamaran.

Gunboat 68 is one of the fastest cruising cats out there, with its maximum speed at more than 30 knots . Gunboat 68 can achieve these fast speeds, thanks to its lightweight construction and narrow hull design.

Still, Gunboat can customize your ship’s plan to accommodate your needs. Whether you are looking for a faster, more lightweight boat with a more extensive sail or a more comfortable cruiser, Gunboat 68 is an excellent option for you.

Specifications

Maximum Speed: 35 knots
Length: 68 ft (20.75 m)
Beam: 29.9 ft (9.1 m)
Draft: 3.9 ft (1.2 m) board up and 9.84 ft (3.8 m) board down
Displacement: 23.7 tonnes

TS 42 (ORC 42)

The TS, or Tres Simple , cruising catamarans, designed by Marsaudon Composites, are some of the fastest cruising catamarans in the world.

Marsaudon developed the ship’s plans using racing boats’ streamlined designs and combined them with a cruising catamaran’s comfortable living spaces. The TS 42 has an inverted hull which helps it glide on the water swiftly without requiring much fuel, but it also has a spacious below-deck area with plenty of luxuries.

TS cruising catamarans are often considered the fastest cruisers on the market, with their speed comfortably reaching upwards of 35 knots in the right wind conditions. Generally, TS catamarans can sail at 20 knots, even with moderate wind. They are the perfect catamaran for racers and high-speed travelers, and yet they still have the amenities of a pleasant live-in vessel.

The TS 42 has a large galley and comfortable cabins, making it a cozy home or vacation vessel. With multiple bathrooms, large windows, and open lounge spaces, these catamarans are superbly comfortable to live in.

The deck and cabin space are divided by a large, openable window, which adds extra light and ventilation to the living areas. It also has plenty of on-deck space, which is rare in such a small vessel with an inverted hull.

If you think I’m using too many confusing nautical terms, you’ll find all the answers on my Catamaran parts explained page .

Length: 42.8 ft (13 m)
Beam: 24.3 ft (7.4 m)
Draft: 4.9 ft (1.5 m) with boards up and 7.5 ft (2.3 m) with boards down
Displacement: 5.8 tonnes

Outremer 45

Based in France, Outremer (pronounced uutremeer 😉 ) designed their Outremer 45 to be a long-lasting cruising catamaran that sails smoothly at high speeds. The Outremer 45 can reach about 15 knots, but the most comfortable sailing speed is 10 knots. However, it can travel up to 25 knots in the right wind conditions, making it a quick ship with all of a perfect cruising catamaran’s luxuries.

It is made for durability from carbon, vinyl ester, and divinycell so that it can last many years without repairs. The Outremer 45 has a narrow hull, and it is designed to be as thin as possible to maximize speed and fuel efficiency. Outremer 45 still has comfortable living quarters with large windows and lounge spaces within the boat. Indeed, it sacrifices no comfort for speed.

In this article, I talk a lot about catamaran characteristics, both interior and exterior, if that’s something you want to better understand, then I recommend an article where I write about trade-offs in design choices .

The Outremer 45 was initially designed to be a boat that would last 50 or more years, and it excels in its durability. It has an open, uniquely expansive side deck and plenty of on-deck conveniences that make sailing a breeze in the ORC50.

With supreme safety features such as tall railings, slip-free grips on deck, and enclosed lounge spaces, it is one of the safest catamarans available (is safety your top concern? I wrote a list of the safest catamarans on the market).

Maximum Speed: 25 knots
Length: 48 ft (14.6 m)
Beam: 23.3 ft (7.1 m)
Draft: 3.3 ft (1 m) with boards up and 6.7 ft (2.04 m) with boards down
Displacement: 8.2 to 11.1 tonnes

Marsaudon Composites ORC50

Marsaudon Composites designed the ORC50, or Ocean Rider Catamaran 50, with both speed and comfort in mind. The ORC50 can be used for cruising, but it is also a great racing boat that has been awarded honors from many races worldwide.

Marsaudon borrowed designs from racing skippers to plan the ORC50, bringing together a cruiser’s comfort with the speed of an award-winning racing boat.

This cruising catamaran is lightweight, which allows it to gain speed at a fast rate, but still has comfortable living quarters inside the boat. It has a rotating carbon mast, which helps to eliminate turbulence over the mainsail and therefore increasing sail efficiency and speed!

With strong winds, the ORC50 can reach up to 23 knots , making it extremely fast for a cruising catamaran. The ORC50 can easily reach speeds much faster than the wind speed, which is a unique quality of this fast, yet comfortable catamaran.

The ORC50 is an excellent long-term living ship with its many organizational compartments, expansive galley, and well-ventilated sleeping cabin. It also has plenty of couches and seating areas built into the boat, and its intuitive design adds plenty of comfort to the cruising catamaran without weighing down the ship.

Length: 50 ft (15.23 m)
Beam: 27 ft (8.2 m)
Draft: 5.6 ft (1.7 m) with boards up and 8.9 ft (2.7 m) with boards down
Displacement: 13 tonnes

FastCat 435

African Cat’s catamarans, including the FastCat 435, are designed for speed and racing. This ship is mainly composed of epoxy, fiberglass, and carbon components, making it very lightweight to ensure that it travels as swiftly as possible.

The FastCat 435 may be as light as possible, but it is durable enough to last for many years in the most extreme conditions.

The FastCat 435 has comfortable living quarters and well-designed comfort spaces so that you can get the most out of your trips. The FastCat also has a green hybrid design, and it uses primarily electric power, which can help you prolong your sailing and use less fuel.

I find solar-powered/electric cats pretty exciting, so much so that I wrote an entire article called The Best Solar-Powered Catamarans on the subject.

The FastCat is an excellent option for anyone who wants a smaller cat with a comfortable design and incredible speed. FastCat’s electric power is also a unique, favorable feature for anyone who wants to use less fuel.

Maximum Speed: 20 knots
Length: 42.7 ft (13 m)
Beam: 24.4 ft (7.4 m)
Draft: 3.9 ft (1.2 m) with boards up
Displacement: 2.4 tonnes

The Lagoon 440 cruising catamaran, like the FastCat, has an electric powering version, which cuts down on fossil fuel usage and ensures that your ship will keep moving. The Lagoon 440 is also among the easiest catamarans to maneuver, thanks to its electric drivetrain and automatic engines.

The speed of the Lagoon 440 usually maxes out at 10 knots with low winds, but with higher winds, it can quickly gain speeds up to 20 knots (some argue even higher, but I’m doubtful). The Lagoon 440 is an excellent cruiser and comfortable catamaran, but it is not an all-out racing cat.

Lagoon is a well-known brand, but there are some caveats, and are Lagoons still making good catamarans?

Below the deck, the living spaces in the Lagoon 440 are magnificent. The ceilings are high, allowing the tallest of passengers to stand in the cabin. The many storage compartments and furnishings have a modern, elegant design. The interior is one large primary cabin with a few private spaces below the deck.

Length: 44.6 ft (13.6 m)
Beam: 25.3 ft (7.7 m)
Draft: 4.3 ft (1.3 m)
Displacement: 10.5 tonnes

Fountaine Pajot Astréa 42

Fountaine Pajot designs some of the most luxurious yet speedy cruising catamarans available in the world. They are renowned for their safe, durable designs that make sailing a comfortable, relaxing experience. And on a personal note, i think the name sounds beautiful!

Their cruising catamarans use an inverted hull design that has become a signature mark of Fountaine Pajot vessels. This hull type allows the water to pass beneath the ship quickly, which increases the speed and fuel efficiency of the cat.

The Astréa 42’s primary benefit is its spacious, comfortable living quarters and large, open deck spaces. The ship’s interior spaces have large windows, large lounging areas, and plenty of storage compartments.

The cabin’s ventilation is also excellent, which reduces the classic musty smells of sea living. You can also get two different models of this catamaran, either in a one-cabin option or a two-cabin option, making it an excellent vessel for larger or smaller families.

The Astréa is ideal for long-term sea living and family vacations (it is not as fast as some more racing-oriented cats). Although the Astréa is not the speediest cat available, with its speed maxing out at about 10+ knots, even in favorable wind conditions, its luxurious atmosphere and comfortable cabin spaces make up for its relatively slow speed.

Don’t get me wrong, despite its lower speed compared to the boats on this list, the Astréa 42 can still get you places quicker than many other cruising catamarans (and most monohulls). So, if you want all of the elegance and comfort of a cat and are not too worried about racing, this ship is an excellent option for you.

Maximum Speed: 10 knots
Length: 41.3 ft (12.6 m)
Beam: 23.6 ft (7.2 m)
Draft: 4.1 ft (1.3 m)
Displacement: 12.3 tonnes

Privilege Signature 510

The Privilege Signature 510 is a long-distance cruising catamaran designed for long-term voyages and sailing in extreme weather conditions. It features a durable, weatherproof design that will protect you from rainy and cold weather while sailing.

The helm and living spaces are completely covered, making it safe to live in, even in cold or stormy weather. It also has an automatic sail adjustment system with the controls at the helm, allowing you to make any adjustments from the helm’s safety and comfort.

Privilege Signature 510 also has an elegant, well-designed living space with plenty of amenities, including an accelerated cooling system, a spacious bathroom and kitchen, and plenty of windows for natural lighting.

With an elegant floor plan, this cozy ship is perfect for long-term living.

The Privilege Signature is not the fastest catamaran on the market, with a maximum speed of around 13 knots. Still, it is one of the quicker cats considering its elaborate amenities and comfortable size.

Maximum Speed: 13 knots
Length: 50 ft (15.24 m)
Beam: 26 ft (7.98 m)
Draft: 5 ft (1.57 m)
Displacement: 25 tonnes

Although cruising catamarans are great boats for slowly cruising along the water, they can also be swift, substantial racing boats that reach speeds of up to 35 knots. These speedy cruising catamarans still come with all of the amenities of leisure boats, but they also reach incredible speeds without rocking or tossing.

Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran!

Catamaran Hull Design

Post author By Rick
Post date June 29, 2010
2 Comments on Catamaran Hull Design

Part 1: Notes from Richard Woods

Since the America’s Cup experimented with going multihull, there’s been a lot of interest in catamaran performance and the catamaran hull designs that define performance. Many guys are investigating whether to buy a catamaran or design and build their dream boat. Let it be said here that building a large catamaran is not for the faint of heart. People begin building 100s of boats a year, yet few are ever completed, as life always seems to have a way of interfering with a good boat build.

Never the less, since the rest of this website is about selecting and buying a boat , it only seems fair to have at least one webpage that covers catamaran design. This page contains notes on boat hull design goals and an accompanying page from Terho Halme has mathematical formulas used in actual catamaran hull design. It has become a popular research stop and an important reference to the catamaran design community.

The content of this page was reproduced from the maestro of Catamaran designs, renown British naval architect, Richard Woods, who not only designs catamarans, he sails them across oceans…. repeatedly. He has a lot to say on the subject of catamaran hull design.

“…When it’ all said and done, the performance of a sailing catamaran is dependent on three primary specs: length, sail area and weight. If the boat is longer it generally means it’ a faster boat. If she has more sail area, it means she’ a faster boat and if she’ light it means she’ a faster boat. Of course, there are limits: Too much sail area capsizes the boat in brisk winds. If the boat is designed too light, she will not take any kind of punishment. Too slim a hull design and the boat becomes a large Hobie Cat capable of only carrying your lunch. Of course, too long and large and you’d have to be Bill Gates to afford one. Then there are lot of additional and very important factors like underwater hull shape, aspect ratios of boards and sails, wet deck clearance, rotating or fixed rigging and so on….” Richard Woods

All Catamarans are not equal, but all sailboats have two things in common: They travel on water and they’re wind powered, so the Catamaran design equations in the 2nd part should apply to every catamaran from a heavy cruising Cat to a true ocean racer.

Richard Wood’s comments on catamaran design:

We all know that multihulls can be made faster by making them longer or lighter or by adding more sail. Those factors are the most important and why they are used as the basis of most rating rules. However using just those figures is a bit like determining a cars performance just by its hp and curbside weight. It would also imply that a Tornado would sail as fast forwards as backwards (OK, I know I just wrote that a Catalac went faster backwards than forwards)

So what next?? Weight and length can be combined into the Slenderness Ratio (SLR). But since most multihulls have similar Depth/WL beam ratios you can pretty much say the SLR equates to the LWL/BWL ratio. Typically this will be 8-10:1 for a slow cruising catamaran (or the main hull of most trimarans), 12-14:1 for a performance cruiser and 20:1 for an extreme racer.

So by and large faster boats have finer hulls. But the wetted surface area (WSA) increases proportionately as fineness increases (for a given displacement the half orange shape gives the least WSA) so fine hulls tend to be slower in low wind speeds.

The most important catamaran design hull shape factor, is the Prismatic Coefficient (Cp). This is a measure of the fullness of the ends of the hull. Instinctively you might think that fine ends would be faster as they would “cut through the water better”. But in fact you want a high Cp for high speeds. However everything is interrelated. If you have fine hulls you can use a lower Cp. Most monohulls have a Cp of 0.55- 0.57. And that is about right for displacement speeds.

However the key to Catamaran design is you need a higher Cp if you want to sail fast. So a multihull should be at least 0.61 and a heavy displacement multihull a bit higher still. It is difficult to get much over 0.67 without a very distorted hull shape or one with excessive WSA. So all multihulls should have a Cp between 0.61 and 0.65. None of this is very special or new. It has been well known by naval architects for at least 50 years.

There are various ways of achieving a high Cp. You could fit bulb bows (as Lock Crowther did). Note this bow is a bit different from those seen on ships (which work at very specific hull speeds – which are very low for their LOA). But one problem with them is that these tend to slam in a seaway.

Another way is to have a very wide planing aft section. But that can increase WSA and leads to other problems I’ll mention in a minute. Finally you can flatten out the hull rocker (the keel shape seen from the side) and add a bustle aft. That is the approach I use, in part because that adds displacement aft, just where it is most needed.

I agree that a high Cp increases drag at low speeds. But at speeds over hull speed drag decreases dramatically on a high Cp boat relative to one with a low Cp. With the correct Cp drag can be reduced by over 10%. In other words you will go 10% faster (and that is a lot!) in the same wind and with the same sails as a boat with a unfavorable Cp. In light winds it is easy to overcome the extra drag because you have lots of stability and so can fly extra light weather sails.

The time you really need a high Cp boat is when beating to windward in a big sea. Then you don’t have the stability and really want to get to your destination fast. At least I do, I don’t mind slowly drifting along in a calm. But I hate “windward bashing”

But when you sail to windward the boat pitches. The sea isn’t like a test tank or a computer program. And here I agree with Evan. Immersed transoms will slow you down (that is why I use a narrower transom than most designers).

I also agree with Evan (and why not, he knows more about Volvo 60 design than nearly anyone else on the planet) in that I don’t think you should compare a catamaran hull to a monohull, even a racing one. Why chose a Volvo 60/Vendee boat with an immersed transom? Why not chose a 60ft Americas Cup boat with a narrow out of the water transom??

To be honest I haven’t use Michelet so cannot really comment. But I have tested model catamarans in a big test tank and I know how inaccurate tank test results can be. I cannot believe that a computer program will be better.

It would be easy to prove one way or the other though. A catamaran hull is much like a frigate hull (similar SLR, L/B ratios and Froude numbers) and there is plenty of data available for those. There is also a lot of data for the round bilge narrow non planing motorboats popular in the 1930’-50’s which again are similar to a single multihull hull.

One of the key findings I discovered with my tank test work was just how great the drag was due to wave interference between the hulls. Even a catamaran with a modern wide hull spacing had a drag increase of up to 20 % when compared to hulls at infinite spacing. One reason why just flying a hull is fast (the Cp increases when you do as well, which also helps). So you cannot just double the drag of a single hull and expect to get accurate results. And any speed prediction formula must include a windage factor if it is to give meaningful results.About 25 years ago we sailed two identical 24ft Striders next to each other. They were the same speed. Then we moved the crew of one boat to the bow. That boat IMMEDIATELY went ½ knot faster. That is why I now arrange the deck layout of my racing boats so that the crew can stay in front of the mast at all times, even when tacking or using the spinnaker.

I once raced against a bridge deck cabin catamaran whose skipper kept the 5 crew on the forward netting beam the whole race. He won.

Richard Woods of Woods Designs www.sailingcatamarans.com

Tags Buying Advice , Catamaran Designers

Owner of a Catalac 8M and Catamaransite webmaster.

2 replies on “Catamaran Hull Design”

I totally agree with what you say. But Uli only talk sailing catamarans.

If only solar power. You need the very best. As limited watts. Hp.

The closer to 1-20 the better.

Closing the hulls to fit in cheaper marina berth. ?

You say not too close. But is that for sailing only.

Any comment is greatly appreciated

Kind regards Jeppe

Superb article

Yachting World

Digital Edition

Catamaran cruising: everything you really need to know

Nikki Henderson
September 21, 2022

Expert skipper Nikki Henderson reveals what you really need to know before going bluewater catamaran cruising

It has become routine now for me to bookend the summer sailing season with a trip to the south of France for the biannual ‘Outremer Week’. This hugely popular event gathers 100-plus new Outremer catamaran owners for five days of training, both in the classroom and on the water, and three days of friendly racing. The goal is to educate future owners so they are as prepared as they possibly can be for their upcoming bluewater catamaran cruising plans.

It’s an intensive week of 12-hour days, with a lot of information to absorb. Unsurprisingly there are some discussions specific to bluewater catamaran cruising that come up repeatedly, and they apply to owners or prospective owners of all brands of bluewater multihull. Here are some of the most common questions people ask me:

What sails should I buy for a cruising catamaran?

Every day after sailing a new catamaran owner will come up to me and say, “Nikki, I’d love to take up some of your time and rack your brains about sail selection .”

To pitch my advice appropriately, I always ask some key questions about your catamaran cruising plans, and I’d encourage you to ask yourself the same.

What is your route plan?

Tradewind sailing will be predominantly downwind. So, focus your attention on downwind sails. A route involving more upwind requires more focus on headsails. Routes involving more upwind tend to be more coastal routes, or schedules with strict timings that will reduce the option to wait for downwind weather windows.

All bluewater sail plans will need storm options. Three reef points in the main is a must, or at the very least an extremely generous second reef. A storm headsail is another key component. Ideally it should be possible to hoist the storm jib up over the top of your furled foresail. In very big conditions, reliance on the thin furling line gets quite nerve-racking.

Catamaran cruising sail options range from symmetric spinnakers to Code sails for reaching performance. Photo: Nicolas Claris

How performance-orientated are you?

Performance catamarans are designed to sail angles downwind, ideally with an asymmetric spinnaker wardrobe. However, there is a cost to the incredible speeds that you can attain reaching on these boats: comfort. So, a key question is what is your attitude to speed versus comfort?

Performance-focused sailors are typically racing sailors, sailors without kids, or sailors who are in good physical shape. If you fit this category, then I’d advise purchasing one heavy weather flat-cut asymmetric sail that can withstand a squall up to 40 knots, and a rounder, lightweight sail that you can sail quite deeply in light to moderate conditions.

If you don’t have a taste or attention span for speed, then one heavy weather symmetric spinnaker (approximately up to 40 knots TWS) should be enough. This will allow you to sail a rhumbline course, and make night-time take-downs less of a worry because the kite will survive a squall.

For upwind, if you will enjoy fine tuning your boat to get that extra half a knot, your ideal option is a large genoa for drive in light to moderate conditions, and a small flat blade-shaped jib for heavier conditions – small enough that it does not need to be furled to an inch of its life to cope with a Force 6. If an inner forestay is an option, the latter could be a staysail which will keep the centre of effort low and reduce sideways drift.

For anyone less performance orientated in their catamaran cruising, the key for upwind sailing is a strong, flat jib that is not too big. Mark three reef points on the foot with sail tape. Keep an eye on how much it stretches and don’t be surprised if you need to change it every few years to avoid losing 5-10° of height.

Downwind the tradewind route logic applies: performance sailors should invest in asymmetric and non-performance sailors in symmetric spinnakers.

Left: taking videos and photos to remember key points of spinnaker handling technique. Photo: Robin Christol/Outremer

Who’s the crew?

At this point, the conversation often goes full circle. Sailors get enthusiastic about performance, and then remember that the kids will need home schooling, or that this is a retirement plan with potential health and fitness considerations.

Most sail changes will require more than one person, and conditions at the bow can be bouncy. Crew also have to be able to sleep, cook, and live on the boat while it is thrown about. If you are short-handed, you could compromise for downwind sailing by choosing furling sails.

A furling asymmetric such as a Code D can replace the ‘hoist and drop’ asymmetric. Or you can make the sock line on a symmetric long enough to route back to an electric winch.

Upwind sailors could compromise by returning to a single jib and consider altering routing to sail slightly off the wind but faster; optimising for VMG. If you have a staysail, ensure it could be furled and therefore left rigged at sea – though make time to speak to the yacht designer about the impact on stability that having two heavy furled sails up continuously could have on the boat.

How ‘eco’ and time-conscious will you be?

Do you care about motoring? Increasingly for many of us, awareness of climate change is a strong motivator to avoid using the engine. And will you be more focused on the destination or more interested in the journey?

If you are keen to avoid motoring, and you are free of time constraints such as fixed crew changeovers or grumpy children who need to stop and swim, then I’d recommend you invest in a Code 0. A Code 0 can double or even triple the boat speed: in 6 knots of wind, an Outremer will sail at 2-3 knots with a jib, but 5-6 knots with a Code 0. It’s a great sail and worth the investment, but first work out if you will use it. They often have low wind limits – around 15 AWS – which upwind could be 10 knots TWS.

Code sails for reaching performance. Photo: Balance Catamarans

When do you reef a catamaran?

Many bluewater cruisers will reef down before dark every night. I’m not a huge fan of this as a rule; reefing should be straightforward enough to not be an intimidating manoeuvre in the dark.

But all new catamaran owners who are planning to go bluewater cruising are concerned about knowing when to reef, especially if they come from monohull sailing, as a catamaran communicates whether it is overpowered or not in a much more subtle way.

You want to conserve your equipment while sailing the boat effectively. So aim for the least amount of sail necessary to achieve your target speeds and angles. The best way to get to know this is to put reefs earlier or later each time and take note of whether it was beneficial or not. Over time you will know your boat very well.

Sailing favours guidelines over hard rules, but it’s good to have a starting point so here are some general ranges. For more cautious sailors or bigger sea states, use the more conservative side of the wind range:

Reef 1 in at 15-20 knots TWS
Reef 2 in at 20-25 knots TWS
Reef 3 in at 25-30 knots TWS

Note that I am using true wind and not apparent. When sailing downwind it’s tempting to fly more sail because the apparent wind is so low. However, if you need to turn upwind – perhaps to reef – the 12 knots AWS in 20 knots TWS will quickly become closer to 25 knots AWS.

Reliance on numbers is great until the wind instruments stop working (it will happen at some point). Remember your RYA Competent Crew course and use the descriptions of the sea surface at various Beaufort Scale forces to identify how windy it is.

How to share roles is a frequent question among couples planning a catamaran cruising adventure. Photo: Robin Christol/Outremer

There are other telltale signs that the boat gives if she needs a reef. Although hulls don’t fly unless you are at the performance level of a Gunboat or similar, you may feel the windward hull just slightly lifting. This is a sign that a reef might be needed. Another is if the bows are diving down when you are sailing downwind. Heel angle can be most obviously sensed while lying down.

The main hindrance to learning when to reef – and when not – is a hesitation to perform the manoeuvre. If taking a reef feels arduous, people avoid it. I admit I can find myself in this camp: I have to remind myself that it’s a win/win, either it’s the right decision and the boat sails better, or it’s wrong and I’ve learnt from it.

The key to reefing is to practice. Taking a reef should be possible to do in under two minutes, especially if you have fast electric winches.

It’s handy to have the option to reef downwind, especially if you’re tradewind sailing. Fully battened mainsails struggle to come down so set up downhaul lines from each reef tack point. Run them through the reefing point on the sail and through the reefing points on each side of the mast so the sail is pulled down in line with the track. Watch out for chafe on the back of the main if reefing a lot downwind, and add spreader patches to your sail where applicable. Centring the traveller during the manoeuvre can help, but keep your eyes looking up and check nothing is getting caught.

Also practice solo reefing ; aside from the possibility of needing to reef alone, this also builds a big picture understanding of the whole manoeuvre. It means reefs are put in faster because anyone can work anywhere.

Catamaran designs at the ARC start cover a full spectrum of performance. Photo: James Mitchell/WCC

How can couples close the ‘experience gap’?

The argument for both halves of a cruising partnership being competent on board has always been that if something happens to the skipper, their partner will know how to safely get to a port of refuge.

However, most people assume that this will simply never happen to them, or they practise parking a couple of times, pick a fender out the water – then never think about it again. The difficulty with starting a bluewater sailing project with a large experience gap is that it tends to widen over time. Each day as leader will be a learning opportunity for the skipper.

They will grow in competence and confidence. Meanwhile, the first mate’s skills will suffer. They will get used to following instructions, their confidence will decrease, and a habit of helplessness will develop. Then, when an emergency does occur, they’ll be in a worse position to take charge than when they started.

It’s critical that couples approach buying a bluewater catamaran for cruising as a team exercise from day one – for both safety and enjoyment. Ideas on how to level up your partnership include:

Rotate roles each day, or follow a rota. Who drives the boat into dock? Who makes the navigation calls (do this passage by passage)? Who does the safety checks? Who runs the watermaker?
Divide the boat – maintain one hull each and share the saloon. This forces you to both understand how everything works from bilge pumps and engines to steering gear and gear storage.
Take a coach with you for the first few crossings. It can be hard to learn to sail from your spouse. A professional coach will force you into a learning environment. They will also create space for the less experienced to be able to take charge in a safe way.
Sail the boat without your partner. Creating a scenario where your leadership role feels natural is the optimum way to practice skippering. So, invite a few friends who don’t know as much about sailing as you, and go for a low pressure cruise. It’s a brilliant confidence builder, and a chance to develop your own style and your own voice on board.

Do you have the skills for a faster cat? Photo: Rick Tomlinson

Production or performance cruising catamaran?

A common view is that you pay more for less when you buy a performance catamaran: fewer creature comforts, less living space, fewer berths, bathrooms, and instead get narrow hulls and sparse design. So, is the big price tag worth the upgrade in performance?

If you are lured by the comfort of a production catamaran, but plan to sail intensively around the world for the next five years, it might not actually be the most comfortable option. No dishwasher or air conditioning is going to make a boat feel safer in a storm. Conversely, why buy a performance catamaran if you plan to leave the boat at the dock for 10 months a year?

Ask yourself if you have the skills to harness the performance of a faster catamaran? And if not, how prepared are you to invest time into learning how to use the boat to her full potential?

A common justification for buying a performance catamaran is that it can outrun bad weather and therefore is safer. But you cannot take advantage of that option if you sail everywhere with three reefs in the main because you are nervous of the boat’s power.

Similarly, the power of performance catamarans comes in part from how light they are. If you load the boat with extras – personal gear, kitchen appliances, heating, aircon – you will quickly reduce a lot of the speed and safety advantages you’re paying for.

The dream – catamaran cruising in paradise! Photo: Robin Christol/Outremer

How to handle heavy weather in a cat?

A popular heavy weather strategy is avoidance: account for global weather patterns when planning your passages to ensure you sail during the more favourable months; invest in a good satellite connection to download accurate forecasts so you can see bad weather coming; use your boat speed to position yourself out of the predicted storm track; be flexible with departure windows and leave at an optimum time.

However, do not misinterpret avoidance of heavy weather as a safety net. With weather systems becoming increasingly extreme and unpredictable (see page 38), this risk management strategy is becoming less and less dependable.

Develop scenario plans for the type of boat you have so that you don’t have to start with a blank sheet of paper as a storm approaches.
In all scenarios, on all boats, avoid 90° wind and waves. Your boat is at its least stable in these conditions. Sail with the weather forward or aft of the beam.
Keep an eye on heel angle. Reduce sail if you start to see any more than 5° or so, unless you have a catamaran that is designed to lift a hull. Lower the centre of effort by reducing sail, starting with the main.
Set up and practice how to reef downwind in case the weather comes in more quickly than you were expecting.
If you can’t sail as fast as the waves, consider trailing warps to slow you down and help with steerage. You should aim to keep the speed relatively high. The key is to reduce the erratic surfing which drops the bows into green-water troughs. I prefer warps to drogues where possible because we are more familiar with them. Unless you practice using a drogue regularly, you will likely need to read the instructions when you get it out, which isn’t ideal in an emergency.
If waves are breaking over your stern, consider turning into the seaway and holding steady. In a performance cat, you can drop the windward daggerboard, lift the leeward board, and pinch into the wind. In a production cat with no daggerboards, this will be difficult. Running the leeward engine might help you keep your bows into the wind. Watch that there is no back flow of water into the exhaust.
Avoid lee shores at all costs, sea room downwind is key.

Outremer Week crews receiving coaching on sail handling. Photo: Robin Christol/Outremer

When should we go?

How long should you wait after buying a boat before heading out on your first bluewater passage? Whether you spend £100,000 or £1,000,000 on your boat, it’s likely to need some fine tuning. I’ve never heard of a new boat that was perfect.

Some yards will cover the initial issues as part of the warranty, so staying close to the yard is a good idea within that period. Even if you don’t have a warranty, proximity to the yard can help you access parts, boat builders and people who understand how your boat has been constructed.

The flip side is that you want to get going, and experience all the freedoms of your new yacht! Some serious bluewater sailing is also needed to test some of the systems.

Give yourself two to six months before you head out on the first crossing. This is enough to test the boat out, but not so long that ‘passage-anxiety’ builds up and you never actually leave.

Do not treat the first few months as a holiday. This is commissioning, and it is the last stage of the build. Test the boat as rigorously as you can before you leave the proximity of the yard. Complete a couple of substantial offshore passages of 48 hours or more to test the systems. Run everything, including the watermaker. Fly all the sails you own. Sail in fruity conditions relative to your ability (Force 6-8 as a guideline) to see how the boat (and you) cope.

Women’s only coaching groups for catamaran cruising sailors help bridge the ‘experience gap’. Photo: Robin Christol/Outremer

Get some experienced people on board to bolster the crew for the early days. The ideal is to hire a professional coach, as this will make pushing the boat much safer and more fun for you.

Do some training ; the MCA AEC four-day engine course is a really useful opportunity to explore the parts of the engine you are normally too nervous to. A safety at sea course is worth its weight in gold. Use this to put together a safety kit that you feel confident in and that is appropriate for your cruising plans. A basic maintenance course can also be helpful, ideally one that covers beginners’ sail repair, rigging, splicing, and electrics.

Ask other sailors for a good tools and spares inventory list. On top of the standard parts that the equipment manuals recommend, current and previous owners of your boat model will have a plethora of advice.

Confident to cast off

Preparation for any type of bluewater sailing can feel daunting. Training courses and cruisers’ seminars like Outremer Week are a little paradoxical – learning how to insert an IV line in a morning medical session, then toasting your upcoming lifelong dream in the evening. It’s a bit like watching the flight safety demonstration before taking off on a once in a lifetime holiday.

The reality is that bluewater sailing is the most incredible opportunity in the world to be both savoured, and treated with an appropriate level of respect. But the most rewarding thing is to see sailors’s enthusiasm grow as they learn. With the opportunity to make mistakes and ask questions in a supportive environment, everyone develops their own skippering style and mantras.

Knowledge nurtures confidence, and confidence breeds positivity – which all contribute to a safe, and successful bluewater catamaran cruising experience. If in doubt, ask!

If you enjoyed this….

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My Cruiser Life Magazine

Sailing Catamaran Speed

You’ve probably heard that one of the best reasons to get a catamaran is because they’re fast. After all, there’s a race any time there are two sailboats on the same waterway.

But like all things in boating, speed is a relative term. Catamarans seem fast to those coming from slow and heavy monohull sailboats, but cruising catamarans are still pretty slow vessels. There are indeed high-tech racing catamarans breaking speed records all the time. Still, the vessels that most liveaboard cruisers venture out on are only slightly faster than their monohull counterparts.

For this article, we will look at the types of catamarans people live on and cruise on. Forget about those fantastic America’s Cup yachts or those multihull go-fast fishing boats for a few minutes.

I have had experience cruising and living aboard both catamarans and monohulls. For five years, my wife and I enjoyed catamaran sailing on a Lagoon 380. We then switched—for many reasons—to a Cabo Rico 38. The Cabo Rico is a traditionally-designed monohull with a full keel and a heavy displacement. In other words, it’s about as far away from a “speedy” catamaran as one can get.

How fast can a catamaran go, measuring catamaran speed, catamaran speeds vs monohull speeds, sailing cruising catamarans, performance cruising catamarans, racing catamarans, power cruising catamarans, catamaran top speed, faqs – how fast are catamarans.

white sailboat on sea near green mountain under blue sky during daytime

There’s no doubt that catamarans are some of the fastest sailboats around—but there’s also a lot of misinformation and misunderstanding online about how fast they really are.

Realize that not all catamarans are created equally. There are cruising catamarans built to carry their passengers in comfort. And then there are racing catamarans built for nothing but speed. Somewhere in between, there is a poorly-defined category of “performance cruising” catamarans that stir passions.

So, are catamarans fast? Well, it’s all relative. But, if you compare them to monohull sailboats of similar sizes and capabilities, the catamarans are usually faster for several reasons.

The speed difference is even harder to measure in the cruising catamaran category. One of the reasons catamarans beat monohulls during races is because they are built light with no ballast. But a heavily-laden cruising cat ready for an ocean crossing is hardly “lightly loaded.” Will it still beat a similarly heavily-laden monohull? Sure! But probably not by as much as you might think.

Boats measure their speed in knots. Traditionally, this was measured by a tool known as a knot log. The modern equivalent is an underwater instrument with a spinning wheel that effectively measures the speed of the water passing over the hull. So long as no currents are present, that speed will equal the boat’s speed over the ground (SOG).

Satellite navigation allows us to measure our SOG more accurately, but this isn’t a great indication of boat performance since it will be affected by tides and ocean currents.

For landlubbers, one knot is equal to about 1.15 statute miles. So, in other words, when we say that a sailboat cruises at 6 knots, it means it’s going about 7 mph.

But before going any further, consider this—the maximum speed that a sailboat makes is generally a pretty meaningless number. Maybe the knot log pegs to 13 knots for a few seconds, thanks to a strong gust of wind while you’re headed down a large swell. Does this mean you’re driving a 13-knot boat?

A voyaging sailor who has made a long passage will have little interest in this sort of number. When you’re crossing oceans, what really matters is how many miles pass under the keel each day. The more miles you tick off, the shorter the passage. So most sailors learn quickly to look past the “fastest speed in knots” number and find real-world stats on passage miles.

Comparing speeds between radically different sailing vessel hulls is like comparing apples to oranges. Even seemingly similar boats, like “cruising sailboats,” the differences between one and the other are endless.

For example, let’s say you wanted to compare 38-foot monohulls to 38-foot catamarans. The speed of a monohull is limited by waterline length, which means you’d have to look at a hull that is significantly more than 38 feet in most cases. On the other hand, the catamaran is known for long swim platforms on inverse transoms and plumb bows—meaning most 38 foot cats have nearly 38 feet of waterline.

Then, what sort of hull design makes a fair comparison to a catamaran? Would it make sense to compare a transitional, salty 38-footer with a full keel? Probably not. Most sailors interested in the cruising catamaran lifestyle would more than likely be comparing it to a modern monohull with a flatter bottom, fin keel, and spade rudder.

What about the catamaran? There’s a lot of variation in the catamaran field regarding performance. If speed is your goal, you likely want to compare the high-end performance brands—Outremer, Gunboat, HH, and the like. These boats are becoming more popular, but most cruising cats you see on the water are not performance models. Instead, they are the big and comfortable cruisers made by Lagoon, Leopard, or Fountaine Pajot.

Finally, how can you fairly compare the stats? Boats sail differently in different wind speeds and at different points of sail. In other words—there are a lot of variables that make it hard to answer the question, “How fast can a catamaran go?”

Polar charts for each vessel can provide some clues to make a somewhat fair comparison. Polar charts are graphical plots of a sailboat’s performance in different wind conditions and at different points of sail. Manufacturers seldom publish since no two are ever perfectly alike. They are less of a boat specification and more of one sailor’s results for a particular boat. Most owners make their own polar diagrams, but they’re still a tool for those looking to get an idea of a model’s performance in the real world.

Speeds of Various Types of Sailing Catamarans

There are several distinct catamaran classes, and predicting speed means understanding what the designers were building the craft to do. You might be surprised to learn that the first “modern” catamarans popped up in the New England racing circles in the late 1800s. Nat Herreshoff’s Amaryllis is particularly famous from the time .

Since then, catamarans have been synonymous with speed. But in today’s world of many different multihull designs, it’s important to set your expectations accordingly. As you would not buy a Ferrari for its cargo space, don’t expect your minivan to win any races at the track.

Examples of cruising cats include popular models made by the big-three catamaran makers—Lagoon, Fountaine Pajot, and Leopard. However, there are dozens of other companies making these boats. The market and industry for cruising catamarans have never been larger.

Most of these boats are engineered to provide comfortable accommodations for voyaging. They first became famous as vessels for sail charter holidays, where their huge cockpits and private cabins made them much more popular than the smaller and cramped monohull options.

As a result, they’re not built with high-tech components or super lightweight performance rigs. Instead, they’re the catamaran equivalent of a Hunter or a Catalina sailboat—mass-produced on an assembly line. That keeps prices lower than other types of catamarans, but it also means that they’re not winning any races. The makers use traditional layups with end-grain balsa-cored fiberglass to keep costs down. In addition, they usually feature stub fin keels, which are foolproof to sail but will not provide the upwind performance of a lift-making daggerboard.

Still, without ballast and when lightly loaded, cruising catamarans can move. They show their colors in light air when heavy displacement-hulled sailboats usually make their poorest showing. Since these moderate conditions also make for great cruising, these boats can provide a lovely ride in smooth weather.

Cruising catamarans can’t plane or anything, but their narrow hulls create an effect that means they can beat the hull speeds of a similarly sized monohull. Of course, it’s not a precise number since every boat and crew is different, but generally, you could expect speeds to be about one and a half times that of a same-sized monohull.

These catamarans are still rigged for comfort, but they’re built using the highest-quality and lightest-weight materials. While their hulls are rigged for comfortable living, they are generally designed much sleeker than regular charter-style cruising catamarans. The hulls are narrower, and you’re unlikely to see tall flybridges or forward lounge seating.

Several companies are making these boats. But in the world of catamarans, a performance cruiser is the upper end of the market. If you want a car comparison, Lagoons are something like a Chevy sedan, whereas an Outremer is like an M-series BMW. A Gunboat would be even more exotic, like a Ferrari. Not only are they more fashionable brands, but they’re also made to higher standards with cutting-edge designs .

It’s also worth noting that the category of “performance cruising cat” is a sliding scale. Some companies make vessels with better materials and craftsmanship than the cruising cats but aren’t designed for speed. Others build cats that are all about performance with few amenities.

With every new model, companies building these cutting-edge boats are attempting to boost the “performance” and the “cruising” aspect of their vessels. As a result, amenities and speed continue to get better and better.

Any racing sailboat is not designed for comfort. Especially on a catamaran, accommodations take up space and weigh the boat down. True racing vessels are designed to not worry about the crew but optimize every element for speed. Once the boat is designed for the desired performance, they’ll squeeze in bunks and storage wherever they can.

As such, there’s not much point in comparing them to liveaboard or cruising sailing vessels—they are too different. Some modern racing catamarans even fly above the water on foils. This makes for a high-speed boat and a considerable risk for sailors traveling for pleasure. Gunboat tried to make a foiling cruising cat in the G4 model, but it didn’t go so well for them.

Power cats run the same gamut of designs that sailing catamarans do. Power catamarans and sport catamarans designs are popular in powerboat circles for the same reasons they are in the sailing world–their hull designs allow for smaller underwater profiles and high speeds. There are many fast catamarans out there with twin engines and average speeds of well over 70 knots. Most recreational vessels cruise at about 20 knots, however.

Power catamarans also offer a smooth ride, making them a popular choice for large vessels like passenger ferries. There are even military vessels that use two hulls, like the stealth M80 Stiletto .

As you can see, catamaran speeds vary from just slightly better than monohulls to extraordinary flying machines. But cats are about much more than just speed. Their open and bright living space makes living aboard an entirely different experience than living on a monohull. Their cockpits flow into their salons for a full-time outdoor living feel that no other type of vessel can match. There are many reasons to choose a catamaran as a liveaboard sailboat.

How fast is a catamaran?

The answer depends on many other questions, like what sort of catamaran is it? And if it’s a sail cat, how fast is the wind blowing?

Sailing catamarans come in all different shapes and sizes. Some are optimized for living space and comfort, while others are designed with fast cruising speeds being the sole goal of the boat. The Gunboat 68, one of the fastest cruising sailboats currently made, can exceed 30 knots.

The world of power cats is much the same. Some power cats can do well over 70 knots, while most cruising boats top out at around 20 knots.

Do catamarans have a hull speed?

A hull speed is a characteristic of traditional displacement-hulled sailing vessels. The properties of the hull shape under the water create drag that limits the overall speed that the vessel can achieve. Even if you keep adding more power (or more wind), the vessel cannot exceed its designed hull speed for any length of time. Hull speed is a factor of waterline length.

Multihulls, however, have an entirely different underwater profile than monohulls. Their narrow hulls and shallow keels mean that drag is not the limiting factor. With this in mind, designers can tweak catamaran hulls to plane and cruise well above the hull speed of a similarly sized monohull.

What is the fastest cruising catamaran?

The market for fast-moving cruising cats has never seen more innovation than in the past decade. This type of boat has taken off, spurred in part by new designs and the overall popularity of multihulls for cruising. The industry leader in fast multihulls is generally considered the French-based company Gunboat . After all, one of the company’s mottos is “Life is too short to sail a slow boat.”

The company’s largest boat to date is the Gunboat 90 Sunshine . However, the delivery of the company’s current flagship, the Gunboat 68 Condor , from France to St. Maarten, provides some real-world numbers. In the delivery crew’s words, “Our max speed exceeded 30 knots a couple of times, and the max 24-hour run was 328 nm.” To save you the math, that works out for an average speed of 13.7 knots for their best day.

Matt has been boating around Florida for over 25 years in everything from small powerboats to large cruising catamarans. He currently lives aboard a 38-foot Cabo Rico sailboat with his wife Lucy and adventure dog Chelsea. Together, they cruise between winters in The Bahamas and summers in the Chesapeake Bay.

The Cruising Catamaran Performance Debate

Which Cruising Catamaran Performs Better…And Does It Really Matter?

A client recently alerted us to a YouTube video posted by a catamaran dealer that is blatantly misleading and inaccurate. If you listen to this dealer, every catamaran manufacturer, other than the Fountaine Pajot brand, is slow, unsafe, not seaworthy and not fit to be a cruising catamaran.

While we agree that the Fountaine Pajot brand is an excellent product (we sell a lot of them), it certainly is not the ONLY good cruising catamaran in the world. There are many products available that are as good and like so many things, when it comes to choosing a cruising boat, it often boils down to personal preference, especially in this category of cruising catamaran.

2022 UPDATE: You will still find some great information below regarding cruising catamarans, especially if you are in the market to buy one. But lots has happened in the Performance Cruising Catamarans category since this post was written a few years ago, like Catana is back in the game with tons of innovation and a fresh new look. In addition to reading this article, be sure to read:

2022 Performance Cruising Catamaran Comparison
We Bought a Performance Cruiser Catana OC 50

Cruising Catamarans Performance

The dealer in the video our client mentioned to us specifically focused on the superior performance of the Fountaine Pajot compared to some of the competing brands in the cruising category like Leopard Catamarans , Nautitech Catamarans , Bali Catamarans , Lagoon Catamarans , and Catana Catamarans .

The fact is that there is very little difference in speed between similarly lengthed cats in this category. All these catamarans are displacement hulls and they pretty much sail to hull speed with intermittent surfing. Therefore, when sailed efficiently, these cats should have very similar performance.

We hear terms such as power-to-weight ratio (sail area to displacement) bandied about a lot by yacht salespeople of the various boat brands as an indicator of performance. While this is definitely a factor and certainly has an effect on acceleration and light wind performance, it is not the only factor. Some catamaran brands will be faster around the cans in a regatta while others will be better when making long passages.

What one should also consider is that when cruising is that a catamaran’s performance will be dictated by sea state as well as wind speed and direction. In light winds, there will probably be a screecher or asymmetrical spinnaker deployed and in strong winds the sails will probably be reefed. This means that in cruising mode, most sail plans are optimized to the conditions. Therefore, when evaluating a cruising catamaran’s performance, there are many factors to be taken into consideration. This is not a simple cut-and-dried argument.

Catamaran Performance Factors & Calculations

To display the different factors and calculations which are relevant when it comes to catamaran performance, we went to Multihull Dynamics for data and pulled some numbers on the two boats most mentioned in this dealer’s video, namely Lagoon and Fountaine Pajot. Here is what we found on the Multihull Dynamics site:

Base Speed – An empirically derived indicator of the speed a given boat could average over a 24-hour period (best days run) under a variety of conditions. Here again the Lagoon had better numbers with 9.82 knots versus 9.46 knots for the FP Helia 44 – this explains why the Lagoons are so successful on the long Ocean races like the ARC
KSP – Kelsail Sailing Performance number is a measure of relative speed potential of a boat. It takes into consideration Sail area, Displacement and length at Waterline. The higher the number the higher the speed predicted for the boat. Here the FP Helia 44 at 6.06 had better numbers than the Lagoon 450 which comes in at 6.02 – the Helia is the lighter boat.
TR – Texel Rating provides a handicap system for widely varying boats sailing together in a race. The formula is essentially the inverse of the Base Speed formula with constants applied to make the results useful. The Texel rating system permits the calculation of time to sail a given distance. Thus a boat with a higher TR can be expected to take longer from start to finish than a boat with a lower TR. The Lagoon 450 came in at 141 versus the FP Helia 44 at 144.
Interestingly the Leopard 45 came in with better numbers than the Lagoon and the FP as follows: Bruce number – 1.25; Base Speed 10.65; KSP 7.68 and TR 122.
The numbers for Antares PDQ44 are very similar to the Helia 44 and Lagoon 450.
Unfortunately there was no data available for the Bali or current Nautitech designs.

*Disclaimer: All data quoted here was derived from Multihull Dynamics. Catamaran Guru offers the details in good faith and does not guarantee or warrant this data.

>>Click on the pictures above or go to Multihull Dynamics website for a full explanation of the graphs.

While the Fountaine Pajot dealer touts the superior performance of their brand, actual data shows that the Lagoon brand has won more ARC cruising rallies than any other brand of cruising catamaran. These are hardly the statistics of “just a charter catamaran that sails in 50-mile circles and lacks performance”, as is claimed by this dealer. As an example, check out these ARC and ARC+ rally results in which Lagoon consistently features well:

Spirit, Lagoon 450 Flybridge – 1st Multihull
Cat’Leya, Lagoon 52 Sportop – 2nd Multihull
Sea to Sky, Lagoon 450 – 3rd Multihull
Dreamcatcher, Lagoon 52 – 4th Multihull
Sumore, Lagoon 570 – 5th Multihull
Opptur, Lagoon 500 – 6th Multihull
Lea, Lagoon 52 – 10th Multihull
2015: 380 Havhunden, first in ARC+ Multihulls Division in corrected time
2013: 620 Enigma, first in ARC+ Multihulls Division in corrected time
2012: 560 Feliz, first in ARC Multihulls Division in real time
2011: 560 Blue Ocean, first in ARC Multihulls Division in corrected time & third in ARC Multihulls Division in real time
2010: 620 Lady Boubou, first in ARC Multihulls Division & 11th overall in real time

This is NOT an indication of how good or bad one boat over another is, but rather an indication of dealer bias ! We are sure this debate will continue but it is our considered opinion that one should look at the overall boat and not be blinded by issues that might or might not be manufactured by over-zealous sales people. As we have said before, it often comes down to personal preference.

Performance Cruising Catamarans

High-performance cruising cats are becoming more popular and there are a lot more on the market than even just five years ago, but it’s not for everyone, especially if you are not a skilled sailor. Daggerboards and bigger rigs require more skill and are not for the average sailor.

We’ve been racing on and off for years on different catamarans and we’ve always had great fun sailing and surfing at speeds of 15+ knots. But as fun as that is, it can be a white knuckled, wild ride in bad conditions and can leave the crew tired and tense because one has to really pay attention. At these speeds any mistake could be catastrophic since there is so much load on the rig. So, make no mistake, sailing fast in less than good conditions is hard work, particularly when you sail shorthanded.

When only the two of us cruise along on our own boat, we really appreciate the pleasure of gliding through the water at 8-10 knots, relaxed and comfortable. Would we love to be able to coast along at a good clip in very light winds? Sure, we would love to own an Outremer or Catana! But that type of performance cat will cost us probably twice the price of a regular cruising catamaran. Is it worth the money for the average cruiser? Debatable.

With the advancement of technology, more people will eventually be able to sail these performance cats skillfully and will be able to afford them as costs come down but until such time, we believe that the average sailor can very happily sail at fair speed toward their destination, safely and relaxed on an average cruising catamaran as discussed above. The fact is, one or two knots of speed, which is what the difference between these cruising cats MIGHT be, will not make or break your passage.

2020 Update: At the time of writing this article, we owned a Lagoon 450 SporTop , not a rocket ship by any means, but a fair sailing boat. We now own a Bali 5.4 catamaran that is significantly lighter and faster in general as a cruising catamaran and we love the extra speed. However, I have to say that this boat is less comfortable underway than the heavier Lagoon. It is more buoyant, a little more skittish and tend to surf much quicker. So one has to pay more attention in more vigorous conditions. It can be tiring on a long passage, but it sure is fun!

Stephen says, “I personally like the Bali because it is a more lively boat and sails very well – when we picked our boat up in France it was completely empty and bobbed like a cork which we were not used to because our Lagoon was a much heavier boat. Since we have now equipped her with all the world cruising equipment as well as big dinghy, etc. she is a little heavier and a lot more comfortable. It is a fact that weight affects performance – the lighter the boat the better performance one can expect. We flew across the Atlantic when we were nice and light but the boat still performs well now that she is at full cruising weight”.

The Bottom Line

So, to conclude this argument, dealers are always somewhat biased about the products that they represent. Manufacturers go to great lengths and spend a lot of money training their dealer networks to be knowledgeable about their products and represent them well with the buying public. They rightfully expect loyalty from their dealers and expect them to present a positive image to the consumer. We all get that. However, when dealers trash and misrepresent their competition with manufactured issues in order to sell their own products, they do a disservice to the buying public and the industry in general.

We want to hear what you have to say! Tell us about performance on your cruising catamaran and also check out our article on why we chose our own catamaran .

Reminder! Check out these fresh updates on performance catamarans:

Contact us if you have any questions regarding catamarans, Fractional Yacht Ownership or our Charter Management Programs .

Estelle Cockcroft

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13 thoughts on “The Cruising Catamaran Performance Debate”

Thanks for a sober writing. I am the owner of the Lagoon 380 Hahunden, and agter with you. I have a spreadsheet with 75 different cruising cat models and the elapsed times in 29 races, and there is not much difference in perforfance. Can send it if uou want. Greetings.

I would like to see that spreadsheet for sure!

I own a Venezia 42′ and if my boat is part of your spreadsheet I would especially love to see it! Could you please send me a copy even if it’s not on there?

To discuss performance and Lagoon or FP in the same sentence is crass. These are not performance Catamarans, purely floating caravans. They have no pretence to performance only cruising capacity, any indicator of performance is purely coincidental.

I own a Privilege 495 and wouldn’t trade it for any other cat.

Hi Jack, I am interested in the performance of your boat. I understand that mini keels decrease performance considerably. Thanks Di

I would like to point out that the data that you use from Multihull Dynamics is completely flawed due to an inaccurate displacement value. Multihull Dynamcis inexplicably lists the Helia at 14 tons, while Fountaine Pajot and your site list the boat at 10.8 tons. This is quite a big difference and skews all the metrics calculated by the site. The Helia is obviously a lighter boat and performance in catamarans starts with weight, so it is undoubted that the Helia will be more lively than the Lagoon. I totally get your point that that does not mean that it will be more comfortable. Second, on the ARC data front: my father sailed twice across the same route in the Atlantic in the last 10 years and I’m very familiar with the conditions. The trade winds there tend to be rather lively and in those conditions weight will matter less. I would expect to see different results in lighter conditions. All that said, the dealer in question is undoubtedly doing their marketing with an agenda.

Hi Ivan, thanks for your input regarding the Helia 44 weight discrepancy. We are aware of this and it holds good for both vessels. You will note that the Helia 44 shows a displacement UNLOADED of 10.8T while the Lagoon 450 shows an UNLOADED displacement of 15T. In order to get accurate performance numbers we assume that Multihull Dynamics have used a number that represents the LOADED weight of both vessels. This means that for the Helia 44 it went from 10.8T to 14.1T (an increase of 3.3T) and in the case of the Lagoon 450, it went from 15T to 20T (an increase of 5T), since it a larger boat overall with more capacity. Based on the above I think we can safely say that we are looking at a fair and accurate comparison. Your input is really appreciated and we are always open to comment and correction to ensure the information we put on the site is accurate and fair.

Thank you for the clarification on displacement.I do see that they have bumped up the Lagoon 450 displacement as well so that’s a fair comparison. I wish they published that clearly because it changes numbers quite a bit as all manufacturers typically post the weight of their boats unloaded.It looks like the Lagoon makes up for the greater weight with a bigger sail area, so that will probably add up to greater effort needed to manage those larger sails but with modern systems, all these things can be managed. Thank you for the clarification and your insight overall.

I think the misconception people have about “performance” catamarans, is that the reason sailors gravitate towards them is not their speed, it is their ability to sail in light air. If you have a catamaran that will sail at windspeed or close to it in 5-8 knots, you’ll actually sail instead of cranking up the diesel. Those true performance catamarans capable of this that also have all the creature comforts of the Helia/Elba45 or Lagoon450/46, are 50+ feet long, and twice the price unfortunately.

You are so right! Well said.

Good article! For me, the weight includes all the stuff you are taking on a month long (or longer) journey (Full fuel +extra cans, 2 sups, dive tanks and compressor, 4 cases of wine…). My opinion is that the performance cats hull design suffers more when loaded to the gills. Ride quality is also very important and is often glossed over by the performance cat advocates.

You are completely right and that was part of strategy when we raced across the Atlantic with the ARC rally. We knew that all the cats would be loaded to the max for the crossing which no doubt makes them less efficient sailing cats. Fortunately on the Bali 5.4 the buoyancy calculations is for a fully spec’d and loaded boat. So we left and sailed like a bat out of hell right off the bat and we were sailing very efficiently, making 200+ NM distances every day. We figured that as the other cats start using their fuel, water and supplies, they would sail a little more efficiently but by then we would be well ahead of the pack, and it worked. We surprised even the very fast performance cats and all the while eight of us onboard were sailing in complete comfort and were eating gourmet meals three times a day! LOL- Of course the TS’s beat us but it is hardly a fair fight. LOL

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How Fast Do Catamarans Sail? Average Sailing Speed of a Catamaran

In most aspects, sailing a catamaran is very similar to sailing a monohull. If you learn to sail on a monohull then most of the skills are transferable. But, there are a couple of subtle differences that we will analyze further in this article. A catamaran is generally more balanced on the water and can be faster than a multi-hull vessel. And, cruising on a sailboat with a cat hull will be much faster than cruising on a sailboat with a monohull. Therefore, a catamaran hull is able to achieve the speeds of a racing monohull and is also more comfortable to sail on.

A tri-hull is even much better as they’re designed towards the performance end of the spectrum. And that is why they double the speed of a racing monohull. So, let’s analyze this subject further in this article and see what’s the average sailing speed of a cat. Follow me!

Catamaran Vs Monohull Speed: Are Cats Faster than Monohulls?

Not all cruising cats are always faster than an equivalent length monohull. But, many well-designed and balanced multihulls can easily surpass the speed of their monohull cousins. And, it’s not fair to mass all cats into one example, but performance cruising catamarans like the Nautitech or Neel trimarans distinguish from others. Their narrow waterline beams, hull chines, deep and fine keels, and rudders as well as efficient sail plans will typically be faster than the average cruising monohull.

“The fun of sailing is proportional to the speed of sailing”, as an American designer, L. Francis Herreshoff, said. And, it’s basically true because when we sail and see another boat heeling in the breeze, we also feel we want to do the same. This is because for many sailors speed means much more than just fun. You should, however, consider keeping your cat as light as possible if you want to maximize speed. I know that keeping your sailboat light is difficult but it’s of importance if speed is your main goal.

Keep in mind that a boat’s speed has won wars and has also been a contributor to safety. In the past, a fast warship was able to outmaneuver its adversary or escape from a boat with more firepower. And just as proven in history, the speed of a sailboat is important and provides a faster boat with more options.

Monohull VS Catamarans Differences

When tacking, you must work hard to keep your speed consistent in the tack and always ease the mainsheet to avoid “windvaning.” When the larger mainsail on a catamaran attempts to turn the boat back towards the wind, this is known as windvaning.
On a monohull, you must be extremely cautious about an unintended gybe. Meaning that you must gybe much more slowly. On a catamaran, you can take advantage of the increased speed and sustain it while gybing to help depower the main.
On a monohull, and when winds increase, the boat starts heeling. This automatically informs you that you have too much sail up and it’s time to reef. And, as catamarans don’t heel, you have to be very careful when to reef the massive main. Most of the time, you will throw in the first reef at 18-20 knots of wind speed. The second reef will be put as the wind gets closer to 23-25 knots. The above-mentioned always depend on the size and type of your vessel.

Wind as a Main Factor for Speed

Thanks to tech evolutions in radar, satellite, and computer technology, a five-day forecast is as accurate as a two-day forecast was back in 1980. A multihull’s higher speed also contributes to easier and safer planning of ocean passages around weather windows since exposure time will be less. Moreover, meteorological prediction for shorter periods is far more accurate. Keep in mind that when sailing faster you also introduce the concept of apparent wind to the strategy of efficient sailing.

Multihull speed upwind? Sailing upwind, the catamaran usually experiences more apparent wind across the deck since it’s sailing faster. Therefore, the sails will feel more pressure, which will make the boat perform even better. And, of course, the concept of apparent wind contributes to the joy of sailing, as it adds another dimension to it. When sailing towards a downwind destination, fast multihulls are able to sail at smaller wind angles. Subsequently, this brings the apparent wind forward of the beam, hence optimizing the angle of attack on the sails.

While cats will fly gennakers, code-zeros, or asymmetric spinnakers, monohulls mostly set symmetric spinnakers to the poles. And most importantly, their boat speed will often cancel out the true wind and will reduce the apparent wind and performance. The faster the multihull is the more it is able to take advantage of the apparent wind and tack downwind towards its destination. Although it might be sailing twice the distance, it will arrive at the downwind mark quicker because its Velocity Made Good (VMG) will be faster.

>>Also Read: How Fast is a Laser Sailboat? Laser Sailboat Top Speed

Performance Characteristics

Bear in mind that cats require four times the power to double their speed. But, a mono-hull vessel requires eight times the power to double the speed. This is due to the fact that a cat has less resistance in the water. However, this is great in terms of conserving and using less energy. Catamarans are also more stable in the water. This stability is effective at resisting heeling or capsizing. In other words, a multi-hull vessel requires four times the force to capsize as a similar-sized mono-hull vessel.

Most of the time, sailing in a catamaran is smoother and facilitates activities that are not always possible on a mono-hull sailboat. In addition, as catamarans have less water resistance, they are generally faster than mono-hull vessels. As their hulls are smaller, this means that they have a smaller bow wave to fight. The bow wave is a wave created by the displacement of water by the bow of a ship. After a certain speed, the boat has to start hauling itself over its own bow wave. Meaning that the larger hull a boat has, the larger its bow wave will be and the more power will be required in order to fight it.

Since catamarans have two small and narrow hulls, they don’t have much of a bow wave. This is one of the reasons they are normally quicker than a monohull vessel of comparable size. Catamarans can travel at speeds of up to 30% faster than monohull boats. Catamarans have the disadvantage of taking longer to transform than monohulls.

Lastly, the thing that makes monohulls harder to sail is heeling and smaller spaces. In stronger winds, monohulls tend to heel. This results in making most tasks a bit more difficult to perform. Whether you’re heading forward to reef, trying to winch in a sail, or move about the boat, sailing on a heeling boat is always more difficult. However, cats have extra stability and room, and this allows for much easier movement around the boat as they do not heel. And, for this reason, catamarans are often considered easier to sail.

How Fast Are Catamarans Compared To Other Boat Types?

There are two main factors that determine the speed of ships. The first one is the hull type. There are hulls that stay beneath the water more or less than others. But, keep in mind that the less the hull is underwater, the faster it can go. This is due to the fact that the less of the hull underwater, the less the drag created when sailing. The other factor is the length of the boat. And, reasonably, the longer the boat, the faster it can go. Every boat has a maximum hull speed that can’t be exceeded. This can only happen in case the boat can plane on the water’s surface or be lifted on hydrofoils. For most boats, the longer the boat, the higher the maximum hull speed is.

Sailing catamarans typically average about 10 knots while pontoon boats average about 16 knots. As for powerboats, they can average anywhere between 30 and 50 mph. Most average sailboats are designed with monohulls and they average from 6 to 9 knots depending on wind conditions. Generally, sailboats average between 8 and 12 mph, again depending on weather conditions. This includes mono-hull between 6 to 8 mph and cats or trimarans between 9 and 10mph.

Speed and Comfort Considerations For Cats

You have a lot of choices if you choose to buy a catamaran. You have the option of prioritizing speed or comfort. After you’ve decided to buy a catamaran, the type of catamaran you can consider is determined by where you’ll be using it and what you’ll be doing with it. In addition, make sure that you look at what type of water you will be traveling in, your crew members, and what type of speed you want to achieve.

Storage is an important consideration to make before purchasing a catamaran. Due to the beam, or width, of a catamaran versus a regular mono-hull vessel, you are often charged for two slips if you wish to store your boat in a marina. Moreover, catamarans are a great option for those who get seasick because they have a more stable ride and more open air space. You have more windows and visibility since the living quarters are not within the hull and below the water’s surface.

Sailing and power catamarans are both great choices. In addition, for low winds or conditions such as docking in a marina, sailing catamarans may be equipped with backup power engines. Twin-engine catamarans can have more power and precision than mono-hull vessels.

>>Also Read: How Fast Can Sailboats Go?

Main Advantages of Catamarans

Space! If you want to opt for more interior and exterior space then the two separate hulls of a catamaran can often double the amount of social space than a monohull of the same length.
Catamarans are far more stable than monohulls. For this reason, they don’t heel when sailing, and are less prone to rocking when at anchor. This factor also contributes to comfortable sailing.
Catamarans have a shallow draft which allows them to enter shallower areas. Keep in mind that in the South Pacific, most lagoons are 6 to 8 ft in depth. This depth doesn’t allow for monohulls to enter, but a catamaran can easily enter these areas.
Stability is another big plus of cats. A cat isn’t that susceptible to the effects of wave action and it also doesn’t heal the way a monohull does. Therefore, it’s much easier to walk around on deck and within the interior of the cat while underway.
In terms of speed, and mostly for downwind sailing , cats are faster than monohulls. This particularly applies to downwind runs, reaches, and broad reaches.
More light, customizable, and airy living area. On a catamaran, the living space is usually situated in the middle of the boat and built on the bridge deck. But, in a monohull you go down into the hull where it is darker and less airy.
More storage space and room for extra systems, provisions, and general sailing equipment. These may include air conditioning, heaters, oven, watermakers, generators, larger fridges, and freezers, etc. And, if you’re a liveaboard, then living on a cat is far more comfortable than living in a sailboat. You have more interior, exterior, and storage space as well as stability and speed in terms of sailing performance.
Many modern cats have flybridge helms. And of course, no monohull achieves this visibility from the helm provided on most modern catamarans.
The galley, main salon, and cockpit are all located on one level , above the waterline.
Because the majority of living space is above the waterline , there’s a better flow of ventilation on a cat making the need for air conditioning somewhat less important during the daylight hours.
When you plan to set sail, you almost never have to rush around stowing stuff or using bungee cords to hold things in place. Except in relatively rough waters, most things stay put.
Since catamarans lack a large, heavy keel filled with lead, they can float even if they’re holed. Production cats are constructed with so much buoyancy that sinking them is nearly impossible.
Catamarans are usually easy to dock because you have two motors and two rudders. Additionally, there’s also no need for a bow thruster.
Most catamarans are able to turn 360 degrees within their own length.

Average Sailing Speed of Catamarans


Sport Catamarans	30 knots
Cruising Catamarans	15 knots
Racing Catamarans	45 knots
Power Cruising Catamarans	70 knots
Swath Catamarans	30 knots

How Fast Do Catamarans Sail? – The Bottom Line

Bear in mind that not all catamarans are created equal. In other words, catamaran speed is relative. The most important benefit of the speed of a multihull is the ability to outrun bad weather. Meaning that you’re able to average 9-10 knots on a catamaran rather than 6-7 knots on a monohull. Subsequently, this will give you more options in your strategy to avoid bad weather. In general, sailing catamarans typically average about 10 knots. Higher maximum and average speeds are what makes cats distinguish as well as their stability. These are the most important characteristics which makes many sailors prefer cats rather than monohull boats.

Peter is the editor of Better Sailing. He has sailed for countless hours and has maintained his own boats and sailboats for years. After years of trial and error, he decided to start this website to share the knowledge.

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PERFORMANCE TOPICS

Optimising Hull Lines for Performance

This article was inspired by a question about the rocker line in the new 8.5m cat Design 256 and I want to stick to the point, so we won’t turn it into a book, but I’ll discuss two issues, hull fineness ratio and some aspects of the rocker profile.

When you manipulate the hull form you’re adjusting the lines in three planes, waterplanes (plan view), buttocks (side view including the keel rocker) and the section shapes. So you need to be aware of how the shapes are changing in the other two planes as you manipulate any one of these three, or all three globally as is now possible with computer modelling.

There are two fundamental constants that you start with and don’t change throughout the process. The big one is the displacement or the amount of buoyancy you need.

If you make the hull finer by narrowing the waterlines you have to increase the draft or make the ends fuller to get back to the required displacement number.

If you flatten the rocker line you have to increase the hull width, fill out the ends, or square up the section shapes rather than having a V or rounded V.

The other constant is the longitudinal centre of buoyancy. You really can’t do any meaningful shaping of the hull form until you have settled on the these two constants.

A third number that we can plug in as a constant if we want to is the prismatic coefficient which describes bow much volume there is end the ends relative to the cross section shape in the middle of the boat, but in sailing boats this is of less importance compared to other factors.

The hull lines for Design 256, 8.5m Cat. It's that hump in the rocker line - right under the back of the cabin that brought up the question and is one of the key points discussed here.

Hull fineness.

Fine hulls are fast, but only in the higher speed range. There’s a misconception I come across quite a bit that you can add weight and windage and you’ll still be fast as long as your hulls are fine.

Well you won’t be. Your boat will simply sink to find the new state of equilibrium. If your transoms are submerged you’ll have more drag. If your bridge deck is too close to the water you’ll have slamming. Much better to be conservative with your displacement figure in the design stage than overly optimistic.

And fine hulls have more wetted area so you have more drag in light air where friction resistance is the primary drag factor.

I’ve seen promotional material for catamarans stating that the boat has less wetted area because it has fine hulls. For a given displacement the minimum wetted area is described by a sphere (or a semi sphere in the case of a floating object). The more you stretch it out in length, keeping the displacement constant, the more wetted area you have.

The more you make the section shape into a deep V or a broad U with tight corners, as opposed to a semicircle, the more wetted area you have. Add into the equation finer hulls are slower to tack.

So fine hulls are only an advantage if your boat is light and has enough sail area to ensure you’re travelling at speeds where form resistance is greater than skin resistance.

In my view the advantage of fine hulls is often overrated as it applies to cruising cats.

At the other end of the scale the resistance curve is fairly flat up to about 1:9 which is still quite fast in most conditions. From there the resistance rises steeply as the hull gets fatter and at 1:8 and fatter you’re suffering from some serious form drag.

Illustration of buoyancy distribution in catamaran hull

This is the rocker line isolated from the lines plan above (in blue) and and the red line shows a more moderate rocker line that achieves the same buoyancy and maintains the centre of buoyancy in the same position. The bow is to the right.

In the image lower right I've squashed it up and increased the height to make the difference in the lines more obvious.

The difference in the two lines is quite subtle, but races are often won or lost by seconds.

Rocker Profile

So if we’re looking for low wetted area we would want a rocker profile that was even and rounded, relatively deep in the middle and rising smoothly to the surface at each end. But this would give us a low prismatic which is not ideal in the higher speed range, and it’s not ideal for pitch damping which in my view is the critical design factor that is often underrated.

Pitching is slow. It destroys the airflow in your sails and the flow around the hulls, and your performance is suffering from slamming loads.

The single most effective way to counter pitching is with asymmetry in the water planes. You can achieve that in the with a fine bow and broad transom. Or you can achieve it with V sections forward and a flattened U shape aft. Or you can achieve it in the profile view with a very straight run forward and a bump in the aft sections. A flatter rocker line is better for resisting pitching than an evenly curved one with deeper draft in the middle.

The final result is a combination of all three of these factors.

On a cat like Design 256 the weight is concentrated well aft so we need to get buoyancy well aft.

The kink you see in the rocker profile helps to do this. It also helps to keep the rocker straight for most of its length and smooth the water flow exiting the hull aft at higher speeds, possibly promoting some planing effect.

If we had a more even rocker line we would slightly reduce the wetted area, but we would increase the pitching and the water would exit the hull aft at a steeper angle, increasing form drag in the higher speed range.

How much of a bump can you put in there without creating a flow separation, and how damaging would that flow separation be? I really don’t know. The way all of these factors interplay in the various conditions we sail in is very complex.

Ultimately a lot of this work is gut feel nurtured by experience, observing things in nature and most importantly experimenting and trying new ideas.

Is the new Groupama AC45 a breakthrough that will influence the form of racing catamarans into the future? I don’t think anyone has a computer that can answer that. We have to wait and see.

Catamaran hull lines showing symmetric and asymmetric waterplanes

Symmetric and non symmetric water-planes. The blue line with grey fill is the DWL from the design above. As is typical with modern cat hulls the bow is long and fine, the stern is full and rounded. This is the asymmetry that has a damping effect on pitching. The red line on the other hand is more like you would see on a double ended monohull and quite a few multihulls have also used this shape in the past. It's quite symmetric about the pitch axis and does not have good pitch resistance.

Lines plan for the Livewire 28 Catamaran

The hull lines of the new 8.5m Sports Cat Design 256

Mad Max , Previously Carbon Copy . She was designed in 1997 but she's the current (2016) title holder of the Australian Multihull Chamionships (2 successive years) and the fastest inshore racing boat in Australian waters.

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Busting the hull speed myth

julianwolfram
December 13, 2021

Waterline length is not the defining factor in maximum boat speed that we all think it is. Julian Wolfram busts the hull speed myth

Busting the hull speed myth Modern hull forms, like this Jeanneau SO440, use chines to create volume forward while keeping a narrow entrance at the waterline

Modern hull forms, like this Jeanneau SO440, use chines to create volume forward while keeping a narrow entrance at the waterline

Every sailor is delighted when the breeze picks up and the boat really starts to get going with a bone in her teeth.

Julian Wolfram is a physicist, naval architect, former professor of ocean engineering at Heriot-Watt in Edinburgh and a Yachtmaster Offshore who has cruised and raced for 45 years

The crew will want to know how fast she will go and perhaps surreptitiously race her against any similar sized boat in the vicinity.

Speculation may start about what allows one boat to go faster than another – is it the hull shape or the sails?

It is easy to spot good, well-trimmed sails but what about the hull ?

The important part is not visible below the water surface. However there is one key indicator that is often very apparent – the waves generated by the sailing yacht.

When a yacht picks up speed the wave pattern around it grows and the greater the speed the bigger the waves .

The energy in these waves is proportional to the square of their height – double the height and the energy goes up by a factor of four.

This energy comes from the wind , via the sails and rig , making the hull push water out of the way.

If less of this wind energy was wasted in producing waves the yacht would go faster.

When a typical displacement monohull reaches a speed-to-length ratio of around 1.1 to 1.2 (speed in knots divided by the square root of the waterline in feet) up to half the wind energy driving it is usually wasted in generating waves.

The hull speed myth: Half angle of entrance

So how can we tell if a yacht will sail efficiently, or have high wave resistance and waste a lot of energy generating waves?

The answer starts back in the 19th century with the Australian J H Michell.

In 1898 he wrote one of the most important papers in the history of naval architecture in which he developed a formula for calculating wave resistance of ships.

Light displacement cruising boat: The bow of this Feeling 44 is finer than older cruising boats

This showed that wave resistance depended critically on the angle of the waterlines to the centreline of the ship – the half angle of entrance.

The smaller the angle the smaller the height of the waves generated and the lower the wave-making drag.

A knife blade can slice through water with minimal disturbance – drag the knife’s handle through and you generate waves.

The big hull speed myth

For a displacement hull the so-called ‘hull speed’ occurs when the waves it generates are the same length as the hull.

This occurs when the speed-length ratio is 1.34.

It is claimed that hulls cannot go significantly faster than this without planing. It is called ‘the displacement trap’ but is a myth.

Heavy displacement cruising boat: An older design has a bow that is several degrees wider

As an example, consider a 25ft (7.6m) boat that goes at 10 knots in flat water.

This is a speed-length ratio of two. That is the average speed over 2,000m for a single sculls rower in a world record time.

The reason for this high speed is a half angle of entrance of less than 5º. Hobie Cats, Darts and many other catamarans have similarly low angles of entrance and reach even higher speed-length ratios with their V-shaped displacement hulls.

These hulls also have almost equally fine sterns, which is also critically important to their low wave resistance.

The monohull problem

Now a monohull sailing yacht needs reasonable beam to achieve stability and, unless waterline length is particularly long, the half angle of entrance will inevitably be much larger than those on rowing skulls and multihulls .

In his 1966 Sailing Yacht Design Douglas Phillips-Birt suggests values of 15º to 30º for cruising yachts.

Many older cruising yachts with long overhangs and short waterline lengths, for their overall length, have values around the top of this range.

Busting the hull speed myth: A Thames barge is a similar length and beam to a J-Class, but its bluff bow, built for volume, makes it much slower. Credit: Alamy Stock Photo

Newer sailing yachts, with plumb bows, have somewhat smaller half angles and a modern 12m-long fast cruiser may have a value around 20º and a racing yacht 17º or 18º.

Size matters here as, to achieve stability, a little yacht is likely to have a bigger half angle than a large one, such as the German Frers-designed 42m (138ft), Rebecca which has a half angle of entrance of under 13º.

Rebecca also has a fine, elegant stern which helps minimise the stern wave – I’ll come back to sterns and stern waves.

Interestingly the half angle of entrance is not mentioned in the otherwise excellent 2014 Principles of Yacht Design by Larsson et al, although it is currently used as one of the parameters in the preliminary estimation of wave resistance for ships.

While it is still particularly applicable to very slender hulls, naval architects are not generally familiar with Michell’s work.

His formula for wave resistance involves quadruple integrals of complex functions.

German-Frers’ designed Rebecca has a half angle of entrance of just 18°. Credit: Cory Silken

These are not ‘meat and drink’ for your average naval architect, and only a few mathematically inclined academics have much interest in theoretical wave resistance.

Michell’s work is rarely, if ever, covered in naval architecture courses now.

Nowadays the emphasis is much more on numerical methods, high-speed computers and computational fluid mechanics (CFD) using the so called Navier-Stokes equations.

Examining these equations, which apply to any fluid situation, does not give any insights into wave resistance, albeit they can model wave resistance very well when used in the piecewise manner of CFD.

It is very easy to measure the half angle of entrance at the design waterline when a yacht is out of the water.

Take a photograph directly upwards from the ground under the centreline at the bow.

Busting the hull speed myth: Multihulls achieve high speeds due to fine hulls, light displacement and ample stability. Credit: Joe McCarthy/Yachting Monthly

Now blow this up on a computer screen, or print it off at a large scale, and measure the angle with a protractor.

Alternatively, if you have a properly scaled accommodation plan drawn for a level close to the design waterline this will yield a reasonable approximation of the half angle of entrance.

Unfortunately there is not a simple relationship between the fineness of the bow and the wave drag.

But, all other things being equal, the smaller the half angle the better.

It is easy to measure and is a useful parameter to know when comparing yachts.

Stern shape and hull speed

The half angle of entrance cannot be taken alone as a measure of wave drag, and the fairness of the hull and in particular the run aft is also critical.

Just as the half angle of entrance dictates the height of the bow wave, so the fineness of the stern is a key influence on the height of the stern wave.

Consider the water flowing around both sides of the hull and meeting at the stern.

Modern race boats, like Pip Hare ‘s IMOCA 60, combine a fine angle of entrance with wide, flat hulls for maximum form stability and planing ability. Credit: Richard Langdon

If these streams meet at a large angle the water will pile up into a high stern wave.

On the other hand if they meet at a shallow angle there will be less piling up. A fine stern can maintain a streamline flow of water.

However if the sides of the hull meet at the stern at a large angle then the streamline flow will tend to separate from the hull, leaving a wide wake full of drag-inducing eddies.

Continues below…

Understanding how your hull shape responds to waves will keep you and your crew safe and comfortable. Credit: Richard Langdon

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In many modern designs the hull sides are not far off parallel at the stern and it is then the upward slope of the buttock lines that are critical and, again, the shallower the slope the better from a hull drag perspective.

The slope of the buttocks can easily be measured if the lines plan is available and a good indication can be obtained from a profile drawing or a photo taken beam on with the boat out of the water.

Drawing a chalk line parallel to the centreline and half a metre out from it will provide a buttock line that can be checked visually for fairness when the boat is viewed from abeam.

A rowing scull easily exceeds its theoretical max hull speed. Credit: Alamy Stock Photo

Again, the smaller the angle the better – provided the transom is clear of the water.

An angle of more than 17º will lead to separated flow and eddy making. This also happens if the transom is immersed.

The greater the immersion the greater the drag, so weight in stern lockers on modern boats can be critical.

Modern hull design

The modern wedge shape attempts to resolve the conflicting demands of a small angle of entrance, good stability and a fine stern.

The plumb bow extends the waterline forward and, with the maximum beam taken well aft, the hull forward can be relatively narrow, providing a low half angle of entrance.

The stern is wide, which helps achieve good stability, but at the same time the buttocks rise slowly at a shallow angle to the water surface.

This gives a smooth and gradual change in the hull’s cross section area ensuring the water flow remains attached to the hull and that the stern wave is kept low.

A modern cruising boat gains stability from a wide stern, but needs twin rudders

This wide, flat stern also helps surfing down waves and possibly planing.

Some designs have chines just above the design waterline which increases usable internal volume and gives a little more form stability when heeled.

However, as soon as the chine is immersed there will be separation along the chine edge as water will not flow smoothly around a sharp edge.

It is just not possible to get the chine perfectly aligned with the streamlines of the water flow in all sailing conditions and there will be some extra drag at times.

There are two downsides to the wedge- shaped hull.

Overloading aft will create a large increase in drag

First the boat has to be sailed at a small angle of heel to keep the rudder properly immersed and to avoid broaching. This can be offset to some extent by using twin rudders .

The second is that the weight must be kept relatively low.

This is because a relatively small increase in weight causes a big increase in wetted surface area at the stern and hence in the frictional drag which makes the boat slower, particularly in light airs.

This is the downside of slowing rising buttocks and the reason why dinghy sailors get their weight forward in a light breeze .

Displacement Length Ratios

Traditionally for sailing yachts the displacement-length ratio has been used as a measure of speed potential, partly because it is easy to calculate from the yacht particulars.

It is waterline length (in metres) divided by the cube root of displacement (in cubic metres or tonnes).

A heavy boat, such as the Heard 35, will have a value of about 4 to 4.8.

A more moderate displacement boat, such as the Hallberg Rassy 342 or Dufour 32 Classic, will have a value in the range 5 to about 5.5; whilst a racing boat may a value of up to, and even over, 7.

A heavy displacement cruising boat with a fair run aft is less affected by additional weight

However the displacement length ratio can be misleading as making a hull 20% deeper and 20% narrower will keep the displacement the same but will significantly reduce the half angle of entrance and the wave drag.

It is interesting to note a Thames barge in racing trim has the same length-displacement ratio as a J class yacht, but their speed potential is vastly different.

Finally I should mention the older ‘length-displacement’ ratio, which is quoted in imperial units.

This is calculated by dividing a boat’s displacement in tons (2,240 pounds) by one one-hundredth of the waterline length (in feet) cubed.

Credit: Maxine Heath

It is still used in the USA and should be treated with caution.

The myth that your boat’s speed is only restricted by it waterline length does a disservice to its designers, and does little to help you understand how to get the best from her when the wind picks up.

Have a look at how the boat is loaded, how you sail on the wind, your boat handling and how much canvas you ask her to carry and you may discover more speed than you expect.

The remarkable John Henry Mitchell

Pioneer of wave theory

It’s worth saying a little more about the remarkable John Henry Michell.

He produced a series of ground-breaking papers including one that proved a wave would break when its height reached a seventh of its length.

He was the son of Devon miner who had emigrated to the gold mining area near Melbourne.

He showed such promise that he got a scholarship to Cambridge.

He was later elected a fellow of the Royal Society at the age of 35 – not bad for the son of a Devonshire miner.

His brother George was no slouch either – he invented and patented the thrust bearing that is named after him.

The half angle of entrance became the traditional factor for assessing the fineness of hulls.

It is defined as the angle the designed waterline makes with the centreline at the bow.It varies from less than 5º for very fine hull forms up to 60º or more for a full-form barge.

At higher speeds, modest increases in the half angle can give rise to substantial increases in wave resistance.

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Advantages of Catamarans and Catamaran Hull Speeds Calculation

Categories : Marine history
Tags : Marine engineering

What is a Catamaran?

Before going into the advantages of catamarans, I’d just like to define the term. Catamarans are a class of boat that has two hulls, generally equal in size. The hulls are connected by a structure of some sort. Catamaran hull speeds are very high, making them a good choice for recreational uses. Catamaran sailboats are common, but catamaran ferry designs are quickly growing in popularity due to their unique advantages.

The catamaran is a ship design with an interesting history. The twin-hull design was first observed by Europeans in India in the late 17th century, but it was actually invented by South Pacific islanders. The capabilities of catamarans were more or less ignored in the West until 1877, when an American named Nathanael Herreshoff began developing and racing catamarans. His designs were so much faster than traditional monohull designs that sailing authorities banned them from competition for nearly a century. Today, catamarans are a popular design for recreational and racing sailboats, and are being used in efficient, low-wake ferries .

Image: Flickr , Catamaran in Cozumel.

Advantages of Catamarans

Catamarans are, in general, faster than single hull boats. This is due to several factors, the most important of which is the hull shape. Displacement hulls are the most common shapes for single hull craft. A displacement hull is supported on the water entirely by buoyancy effects. This creates a hydrodynamic drag barrier, which slows the craft. Catamaran hulls can be designed as planing or displacement hulls, but they are not slowed nearly as much by the drag barrier. Catamarans reduce drag by making use of a very thin and pointed hull design.

Catamarans are also very light, which further reduces drag and displacement. Catamarans save on weight because the multihull design eliminates the need for a keel counterweight, as the same purpose (righting the ship) is served by the hull spacing. This can make them difficult to turn, however.

Catamarans are also more stable than monohull ships, enabling designers to use more sail per foot of the boat. Stability comes from the wide beam legth; beam length is the distance from one side of the boat to the other. This wide beam and stability also allows catamarans to gain more power from heavy gusts, because they do not tend to heel over like monohulls do.

Catamaran Hull Speed

More efficient single hull boats are designed to travel with a low Froude number, which reduces but does not eliminate the drag barrier. This drag limits hull speed based on a relation involving length at waterline, given by the formula V=(gL/(2pi))1/2, where g is the gravitational constant and L is the waterline length. This is the theoretical limit for single hull displacement craft. Note that ships can sometimes exceed this theoretical limit, but to do so requires a very large power source.

The calculations for a catamaran are more complicated. The formula for catamaran hull speed is 1.34*(wetted length)1/2; however, this drag formula is generally not the limiting factor for catamaran hull speed. This is because boats with waterline length to beam ratios greater than 8:1 are not limited by hydrodynamic drag factors, whereas smaller boats need to plane to do so (planing requires enormous amounts of power for displacement hulls). A more important factor to consider is the prismatic coefficient, Cp. Cp = V/(LBP*Am), where V is the volume of water displaced by the hull, LBP is the length between perpendiculars, and Am is the area at midship.

Very fast boats actually require a high prismatic coefficient, which in turn requires a less-narrow boat. However, narrower hulls can get away with a lower prismatic coefficient. The ideal range of Cp for a catamaran is between 0.61 and 0.65. There are a few ways of increasing the prismatic coefficients: sailors can use bulb bows, a wide planing aft segment, or a flat hull rocker in conjunction with a bustle aft. Though high prismatic coefficients increase drag at low speed, at high speeds they can reduce drag by as much as ten percent.

Catamaran Hulls and Low-Wake craft.

As explained here , catamarans can be used to create low-wake ferries. Because of their wide bows and low weights, catamarans can be made to travel quickly with minimal wake. Catamaran ferries are also more fuel-efficient, because of the previously-mentioned factors.

Image Credit: Wikimedia Commons , Catamaran Ferry

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CRUNCHING NUMBERS: A Better Way to Estimate Hull Speed

It’s been a while since we discussed all those mysterious numbers that both boat designers and journalists are always throwing around to confuse us when they talk about boats. You’ll recall last time I bloviated about displacement/length ratios . One big reason it’s a good idea to go to the trouble to calculate a boat’s D/L ratio is that you can use this number to refine your estimate of the boat’s maximum speed potential beyond the relatively rough estimate afforded by the classic hull-speed formula we discussed earlier.

This more accurate method of finding a boat’s potential top speed, devised by designer Dave Gerr and published in his tome, The Propeller Handbook , can also be used to estimate the hull speeds of multihulls (both catamarans and trimarans). Dave warns, however, that catamarans with very narrow hulls (for mysterious reasons that no one really understands) will often exceed the speeds predicted by his method.

To comprehend Dave’s formula, we first need to comprehend that the famous multiplier we used in the classic hull-speed formula (1.34) is in fact what is known as a speed/length ratio (S/L ratio). This ratio quantifies the relationship between a boat’s speed (BS), whatever it happens to be at any given point in time, and its waterline length, according to a formula that holds that S/L ratio equals a boat’s speed in knots divided by the square root of the boat’s load waterline length (S/L ratio = BS ÷ √LWL).

The brightest kids in class will instantly note that this is simply the classic hull-speed formula (HS = 1.34 x √LWL) run backwards to solve for the speed/length ratio instead of speed. What the classic hull-speed formula assumes is that 1.34 is the maximum S/L ratio that can ever be achieved (due to the characteristics of waves we discussed before) and thus always serves to limit a boat’s top speed potential.

What Dave’s formula does is estimate a boat’s maximum S/L ratio based on its D/L ratio so as to more accurately reflect the fact that lightweight boats are more capable of exceeding their nominal hull speed. Once we’ve arrived at a new and more accurate S/L ratio for a given boat, we can then plug it into the classic hull-speed formula to derive a new, more accurate estimate of that boat’s nominal hull speed.

Dave’s formula holds that a boat’s maximum S/L ratio equals 8.26 divided by its D/L ratio to the .311 power (Max S/L ratio = 8.26 ÷ D/L ratio↑.311). For a 12,000-pound boat with a 28-foot waterline and a D/L ratio of 244, we thus get the following results: 244 to the .311 power equals 5.53 (you’ll obviously need a scientific calculator to figure that out!), therefore 8.26 ÷ 5.53 equals a maximum S/L ratio of 1.49. Plug 1.49 into the hull-speed formula (1.49 x √LWL) and you get a new nominal hull speed of 7.9 knots (1.49 x 5.29 = 7.88), as compared to the boat’s old nominal hull speed of 7 knots (1.34 x 5.29 = 7.08).

This in itself is an appreciable difference, but it grows even larger as the boat grows lighter. Assume, for example, that our 12,000-pound boat has shed 3,000 pounds to become a 9,000-pound boat with the same load waterline length, and its D/L ratio drops to 183. Its old nominal hull speed, based solely on its LWL, remains exactly the same at 7 knots, but its new nominal hull speed, figured according to Dave’s method, now becomes 8.6 knots!

Things get even more exciting if you bear in mind that this revised hull-speed estimate still does not account for a boat’s potential to plane. That is, we’re still only talking about the top potential speed that may be achieved by a hull in displacement mode. Dave further warns that getting the extra hull speed his method predicts will require a lot of extra power, but he does maintain that his method is ultimately more accurate than the old one.

I, for one, happen to believe him. Running Dave’s formula on your own boat and finding out that its top speed is higher than you thought is an easy way to put a smile on your face. Unless you own a classic CCA-style cruiser with long overhangs. These boats have exaggerated D/L ratios, due to their short static waterlines (which get longer when the boat starts sailing and heels over) and when you run Dave’s formula on them you usually get a lower top speed. In cases like this, I always assume the classic hull-speed formula is more accurate.

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I love your blog

Thank you for this information it’s kind of you to share it.

This may be a reasonable estimate for BOATS, but it is not scalable to larger SHIPS. Let me give you an examples. — The Iowa Class Battleship has a displacement of 50,000 long tons and a length of 860 ft. This gives a D/L ratio of 78.6 and a S/L ratio of 2.12. This then indicates that Hull Speed = 2.12 x Sqrt (860) = 62.17 knots. We know that is bullshit because the Iowa has 212,000 shp for it’s 50,000 tons or greater than 4 shp per ton. We also know that it is a 33~35 knots ship depending on load (and hence draft). There is no way her hull speed is 62 knots. — The Queen Mary 2 cruise ship is about 87,000 tons and 1132 ft long. This gives a D/L ratio of 136.8 and a S/L ratio of 1.79. THis then indicates that the Hull Speed = 1.78 x Sqrt (1132) = 59.9 knots. The QM2 has 115,300 shp delivered via her four mermaid pods or about 1.33 shp per ton. In service she is a 28 knots vessel which reached 30 knots during her trials. Again, there is no way her Hull Speed is 60 knots.

Great article but I have a question. How can this be applied to displacement hulls? Specifically to kayaks or surfskis. Does the constants and formulas hold true for this kind of vessels?

I have an Epic v7 surfski which measures 17′ long and weighs 53 lbs. According to the standard hull speed calculations, it has a theoretical hull speed of 5.52 knots. However, if I try to use these formulas, the Boat Speed comes to 20.89 knots. Its creator, an olympic medallist, is able to push it to 7.18 Knots for long distances which could very probably translate to a slightly higher speed for shorter distances; but no one on muscle power alone could drive it to 20 knots or even close to that.

Something clearly needs to be adjusted for it to apply to small displacement hulls.

Did you factor in the rower’s weight? I get 12.9 kts with a 150 pound rower.

Interesting. I am currently boatless and looking at purchasing something in the 30′ range (sail) and comparing potential hull speeds. One boat has a 24 ft waterline and the other 25. I assumed the longer wl would give me a bit more speed as the old formula shows. However the longer WL boat also displaces 1,400 lbs more so by this new formula the shorter boat has the same theoretical hull speed. Good to know. Thanks!

The math shown in the example doesn’t work. 12000/28=428.57 not 244. Raise that to the power of .311 and you get 6.585. 8.26/6.585=1.254

Mark: you need to scroll up and click on the previous article on D/L ratios; (in red) The exact number works out to 243.6, rounded to 244.

Did I miss something, or does David’s sailboat speed-prediction formula ignore sail-area. ,,,& is based only on D/L & boat-length?

So then, is Dave saying that sail-area is irrelevant to a sailboat’s speed?

Hi Michael! Thanks for the comment. The answer is yes, Dave’s formula ignores sail area and treats only the maximum speed potential of any given hull. But no, sail area is obviously not irrelevant. Dave’s formula, like the traditional speed-prediction formula it replaces, merely assumes a sailplan powerful enough to drive the boat at its maximum speed.

I ran into this formula in your book The Modern Cruising Sailboat. Running the numbers for our 31ft double ender gave pretty interesting results:

Traditional hull speed: 6.8kt Gerr’s hull speed (light ship): 7.1kt Gerr’s hull speed (2t load): 6.4kt

Now, there are no polars (or much other performance material) available on our boat, so I’ve constructed polars based on the actual recorded wind speeds and angles vs. actual sailing speeds during last two summers of cruising. And you know what is the top speeds I get there? 6.4kt! Coincidence? Probably not.

I always find these exercises interesting. And probably very worth while to designers, as an end user the only thing that matters is real world sailing characteristics. To reflect on theoretical speed potential of my boat, which has over 700 sisters and an established racing record would just be frustrating. When shopping for a new boat I would look at established history and PERF ratings. They are a long term average of a particular hull form and should predict what the sailor can expect. Theory is would only come into my calculations if I were comissioning a new design, but once she is built the proof is in the boat.

Catamaran Hull Speed

Add to quote

The hull speed formula for displacement monohulls is 1.34 x the square root of the waterline length. When planing, a monohull will exceed it's hull speed. Obviously this formula doesn't apply to catamarans. Even when not planing, they will travel much faster than what the hull speed formula predicts. Is there a formula or general guideline for catamaran hull speed related to waterline length and / or hull length:beam ratio?

Here, read this ...

Few Catamarans are actually planning vessels. Most are semi-displacement boats (like most modern IMS/IRC derived monohulls). Both forms of semi-displacement boats achieve speeds that are higher than normal hullspeed (i.e. 1.34 x the square root of the waterline length) by minimizing wave production. In the case of multihulls, this is done through a very narrow waterline beam to length ratio, and minimal interference between the waves produced by the other hull(s). Semi-displacement mono-hulls cheat a bit by using very fine entries to minimize the size of the bow wave that they produce. In both cases, clean hull forms and minimal drag is critical to overall performance, but properly designed, semi-displacement boats can achieve sustained speeds that can literally exceed twice their theoretical hull speed without planning. Of course as Alex points out, and as the article that he linked to explains, few cruising cats achieve passage speeds that exceed or even match those of modern performance mono-hull cruising boats. Respectfully, Jeff

Thanks guys.

Damn multis. They leave me standing.

Under body shapes: keels and centerboards, Beam & hull-beam ratios, Beam overall – overall wide beam versus standard beam, Displacement but I can`t find any mention of the optimal hight of the bridge deck cabins, Giuliettas post mentions under deck clearance and it`s extremely important but if you build the bridge on top off the bridge deck would that make it extremely unstable as the center of gravity would be to high making the cat useless in any swell.

sctpc said: Under body shapes: keels and centerboards, Beam & hull-beam ratios, Beam overall - overall wide beam versus standard beam, Displacement but I can`t find any mention of the optimal hight of the bridge deck cabins, Giuliettas post mentions under deck clearance and it`s extremely important but if you build the bridge on top off the bridge deck would that make it extremely unstable as the center of gravity would be to high making the cat useless in any swell. Click to expand...

Yes but what would the optimal height formula be I have been reading for over 4 hours since I read this post and lots of designers mention it but is there a rule to it, 'deck should be 2 foot making cabin 9 foot for a 30 foot cat or deck 4 foot cabin roof 10 foot for a 50 foot cat. I find it interesting that all the other design stuff is quite well out explained but none on windage problems ect.

The less cabin, the better from a windage and weight standpoint. There are various rules of thumb for bridgedeck clearance. .06 x DWL is one. As far as hull waterline beam goes, some say 16 to 1 is as good as it gets from a resistance standpoint. A fast cruiser will be about 12 or 13 to 1, but the shorter the boat, the more beam there will be in the hulls in order to get a reasonable amount of room inside and carrying capacity. 8 to 1 hull beam to DWL length is common in small to medium size cruising cats. Overall beam is usually about one half of the overall length. Recent designs are often somewhat beamier overall-BOA 55% of LOA is not uncommon now. Tim Dunn - 65 Foot Sailing Catamaran Design by Tim Dunn

there isn't a basic rule for bridge deck clearance and cabin height. Some designers avoid the problem entirely by not using the bridgedeck form living accommodations. Wharram's design often don't have any living space on the bridge deck.

Check out Performance Cruising Inc. - The Official Gemini 105MC and Telstar 28 Web - I find the boat to be a best of both worlds design in a smallish cruising catamaran. I am of course partial and biased. The hulls are roughly 8:1 length: beam. I've had mine at 10.3 knts SOG in 16 knts on a close reach (50 degrees off the wind) going up current in 1.25 knts of current. Other owners have reported (and photographed) top speeds of 18 knts, and routinely get 10+. From the side the gemini looks like a moderately high windage mono. That's hard to do with a queen sized bed in the master cabin and twin staterooms aft with double beds. It has 39 inches of clearance at the front it takes chesapeake chop well on the nose, but with only 18 inches at the stern we do get the occasional 'thumb' on the floor of the cockpit. Reportedly they do well in typical ocean swell and have crossed the Atlantic and Pacific Ocean quite well. Several reside in Hawaii, having sailed there on their own bottoms, a couple are currently circumnavigating ( theslapdash.com . By making the salon area standing height for only the walk in area and sitting height at the salon table Tony Smith (the designer) was able to give it a nice profile. Otherwise, headroom is 6'2" throughout. I routinely dock my boat in a cross wind of 5 or so knots and I can tell you it parks and tracks as surely as a car with very little problem caused by windage. Mine:

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Fixed it, thanks.

Bridge deck, pounding, and windage So, 3 feet between the bottom of the bridge deck & the deep blue sea. In some cases long and thin is good but can it be taken to extremes? For example a 50' cat with a waterline beam of 2.5' mathmatically will produce a vapor trail at 35+ kts. In reality though, will it? Since I hate doing time in the hulls of any boat I am going to keep the boat light in terms of gear and have a tapered bridge deck encompassing all accomodations with a profile to the wind of about 3'. Add a nice sail plan and I'm having fun! Or at least that is the current plan. So, any thoughts on the long skinny hull thing?

One other point is the overall beam of the boat, especially in the case of a catamaran matters as well. If the beam is relatively narrow for the boat size, the hull wake from the two hulls can interfere with performance.

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determining CATamaran hull speed

Discussion in ' Boat Design ' started by SCATAR , Mar 22, 2010 .

SCATAR New Member

we have a very rigid rather over-engineered heavy (30ton) 18m catamaran. the original owner is deceased and boatyard lost all its records in hurricane katrina. from what I may make of the four engineering drawing found, she sits 8” (±2”) low as a result of the extra alloy. the result is a cat that struggles at 6-7 knots in 20-30 knot winds. we are considering a new sail plan but wanting, feel we are needing, to have a calculation of the hull speed. anyone who would be able to recommend someone, or may themselves be able, to do the requisite calculations to determine hull speed? we are also considering adding 1.5-2m stern with an extended swim platform but wonder about the impact on handling...

marshmat Senior Member

Hi Scatar, There are a few naval architects around this community who specialize in multihulls, although your particular boat might be a rather rare one. We'll see if any of them chime in here.... The short answer is- from my perspective- that I agree with you, 6-7 knots for a 30 ton 18 m cat in 20-30 knot winds is not good sailing performance. (But wow, is that heavy for a sailing cat- is she more of a "charter cruiser" type than a "blue-water" type?) However, knowing "hull speed" is almost irrelevant in this case. The concept of "hull speed" (v = 1.34 * sqrt(LWL) for waterline in feet, v in knots) assumes that the boat is essentially limited to the speed of a wave that's as long as the hull- a rough (at best) approximation for monos, and almost meaningless for cats. Your naval architect, once you find one, will have access to much more sophisticated performance prediction techniques that take into account the actual hull shape, weight, windage, sail plan, sail trim for different points of sail, etc. This is a fairly involved process, as it involves the NA reviewing all the drawings and known data about the boat and preparing computer simulations to determine the effect of various modifications on her performance.

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SeaRescue Catamaran - Versatile 3D-Printed RC Boat

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Looking for a fun, reliable RC boat that can do more than just cruise around? The SeaRescue Catamaran might be your new go-to project. This sleek, 3D-printed boat isn’t just about speed and stability—it’s built for versatility. Whether you're retrieving an RC plane from the water or just enjoying a day at the lake, this boat gets the job done with style.

Why You’ll Love It:

Dual-Hull Design: The twin hulls keep things smooth and stable, so you’re less likely to capsize when the water gets choppy.
Light but Strong: The hulls are hollow and reinforced inside, making them lightweight yet tough enough to handle some bumps.
Maneuverability: Dual rudders give you precise control, making it easy to navigate tight spots or keep a straight line.
Motor Flexibility: Designed around the A2212 brushless motor, but you’ve got room to fit other sizes if you prefer.
Easy Build: The design is straightforward, with all the parts you need to snap together securely using M3 screws and heated inserts.

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Motor: A2212 brushless motor (but other sizes can fit too)
Servo: 9-gram servo for steering
Prop: 8045 or 8060 CCW propeller
ESC: 30A for motor control
Receiver: FS-I6 or similar
Battery: 2s or 3s (pick a quality one for the best experience)
Extras: M3 screws, heated inserts, and some push rod wires for steering

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Print Specs: The design is optimized for typical settings (3 walls, 4 top/bottom layers, 15% infill). You’ll need supports for a few parts, but most of it is pretty straightforward.
Assembly: Super easy with all the mounting points ready to go. I’ve tested it out, and everything fits and works as it should!

What’s Next? I’ve fully printed and tested the SeaRescue Catamaran, and it’s a blast! Whether you need to retrieve an RC plane or just want a cool RC boat for your collection, this catamaran is up for the challenge. If you’re into RC boating, this project is worth the print time.

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Ride Control System Effects on Motion, Slam Load, and Passenger Comfort of High-Speed Catamarans: An Experimental Study in Irregular Waves

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Javanmardemamgheisi, E, Mehr, JA, Holloway, DS, Davis, MR, & Ali-Lavroff, J. "Ride Control System Effects on Motion, Slam Load, and Passenger Comfort of High-Speed Catamarans: An Experimental Study in Irregular Waves." Proceedings of the ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering . Volume 5A: Ocean Engineering . Singapore, Singapore. June 9–14, 2024. V05AT06A076. ASME. https://doi.org/10.1115/OMAE2024-126372

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In recent years, the demand for efficient waterborne transportation has led to the development of high-speed catamarans. However, increased operating speeds result in elevated ship motions, making ride control systems desirable for passenger comfort, crew workability, and operational efficiency. This paper presents comprehensive towing tank experiments on a 2.5 m hydroelastic segmented catamaran model of a 112 m Incat Tasmania high-speed catamaran. These tests assess the impact of different ride control algorithms on the model’s motion and load responses, as well as passenger comfort in irregular head sea waves. The model featured a ride control system with a centrally positioned bow-fitted T-Foil and two stern-mounted stern tabs.

The study analysed ship motion responses, centre bow slam events, and the motion sickness dose value at specific longitudinal locations of the passenger cabin. The results showed that, in moderate waves, a nonlinear pitch control algorithm significantly improved performance, reducing RMS pitch and heave motions by around 32% and 29%, respectively, peak pitch and heave RAOs by 41% and 31%, respectively, and motion sickness at the forward position by 70%. The structural load analysis demonstrated a substantial reduction in the number of slams of 96% and 50% in small and large seas, respectively, using a nonlinear pitch control algorithm. These results demonstrate the considerable potential for further enhancing passenger comfort, structural response, and operational efficiency of high-speed catamarans using an effective ride control algorithm.

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Gunboat 57 charter catamaran will spoil you with speed.

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Gunboat 57 Vai Vai is not your average charter cat.

One of the many perks of my job as a yachting writer is that I get to sail aboard a wide variety of boats. I especially love ripping off speed runs aboard some the world’s largest (and fastest) offshore race boats . Now, the truth is, the only reason I’m allowed aboard is because I’m just a humble journalist. But the blistering speeds those boats are capable of is addictive.

And as someone who’s been lucky enough to sail more than my fair share of charter catamarans in the Caribbean, Mediterranean, French Polynesia and other bucket list destinations, I can say every charter cat I’ve ever been on has been a fantastic platform for living large in the tropics. They’re not particularly exciting to sail.

Gunboat 57 Vai Vai speeds in front of Newport's The Claiborne Pell Bridge

I’m also grateful to say that I’ve sailed on a few high-performance sailing catamarans like the Gunboat 57 Vai Vai . One of the many cool things about Vai Vai is that she’s capable of blow-your-hair-back speeds AND providing just the right amount living space and cruising comforts. But I never knew it was possible to charter something as fast and fun-to-sail as a Gunboat 57—in Newport, Rhode Island in the summer and Caribbean in the winter—until now.

Jeff Hager's Gunboat 57 will appeal to sailors who appreciate high performance sailing and stylishly ... [+] comfortable accommodations on a charter boat.

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After spending a little time with the VaiVai’s owner Jeff Hager earlier this summer, all I can say is Vai Vai ’s speed potential makes it possible to cover way, way more ground than a more conventional charter boat. And since everyone (even the helmsman and sail trimmer can hang out in main bridgedeck area, and the catamaran never heels more than a few degrees) more speed doesn’t mean less comfort.

The Gunboat 57 is a powerful sailing catamaran with stylishly comfortable accommodations and an ... [+] indoor helm station

In fact, the indoor/outdoor living aboard Vai Vai is next level. The wrap-around windows provide protection from the high winds and spray such a fast boat produces. The 360-degree view is amazing while the massive roof provides essential sun protection. And the sheer size of the bridgedeck is soooo much bigger than what you’d find on a 57-foot monohull. And the nice thing about having the galley and living cabins in the hulls is that each cabin is particularly private.

But, let’s fact it. This boat will not appeal to anyone who rates a charter boat based on how over-the-top-“luxurious” the accommodations are. This is a high-performance sailor’s catamaran for people who don’t want to give up the sheer thrill of sailing on a charter.

The boat that will bring oysters and other raw bar staples out to your boat at anchor is one of the ... [+] many reasons to stop in Cuttyhunk on a charter aboard Vai Vai.

And if you’re lucky enough to book a week aboard VaiVai before she heads south in the fall, be sure to stop for oysters on the tiny island of Cuttyhunk. I guarantee you’ll beat every other sailing charter boat in Newport’s fleet.

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IMAGES

Catamaran Hull Speed Calculator For Beginners (Table and Free
The Definitive Guide to Stepped Hulls
Understanding Vessel's Hull Speed And Its Determination
How Fast Do Catamarans Sail? Average Sailing Speed of a Catamaran
Catamaran Hull Speed Calculator For Beginners (Table and Free
Help with calculation for electric catamaran hull: speed, length, with

COMMENTS

Catamaran Hull Speed Calculator For Beginners (Table and Free
This is the formula for Maximum Hull Speed on a displacement boat: Max hull speed= √((Length on Water Line x g) /(2 x pi)) x 3600/1852. Now we need to add the increased efficiency (loss of drag) of a semi-displacement hull, usually, this is somewhere between a 10-30% increase. Semi Displacement hull speed = Maximum hull speed * 1.3.
How Fast Do Catamarans Go? 5 Examples (With Pictures)
Sailing catamarans typically average about 10 knots. Pontoon boats average about 20 mph. A powerboat cruiser can average anywhere between 30 and 50 mph. Cigarette boats can even reach close to 90 mph in the proper conditions. Sailboats average between 6 and 12 mph depending on wind conditions.
Cruising Catamaran Speed! With Examples and Explanation
When the load is higher, power catamarans speed drops to 15-20 knots. ... There are several features of a cruising catamaran that impact its speed. These include: The type of hull. The less the hull is submerged into the water, the faster the catamaran will go. When they are submerged, hulls create drag which slows the velocity of the boat.
Hull Speed Calculator
Hull speed is the speed at which a vessel with a displacement hull must travel for its waterline to be equal to its bow wave's wavelength. ... Catamarans; and; Competitive kayaks. A hull's design can enable it to circumvent the workings of hull speed.
How Fast Do Catamarans Go?
August 30, 2022. ‍ Catamarans are known for their speed, and some vessels are fast enough to break world sailing speed records. Catamarans can go between 15 and 30 knots, with the fastest achieving speeds well in excess of 60 knots. Sailing catamarans are sometimes twice as fast as monohulls and cut through the water with greater efficiency.
The 8 Fastest Cruising Catamarans (With Speedchart)
Their cruising catamarans use an inverted hull design that has become a signature mark of Fountaine Pajot vessels. This hull type allows the water to pass beneath the ship quickly, which increases the speed and fuel efficiency of the cat. The Astréa 42's primary benefit is its spacious, comfortable living quarters and large, open deck spaces.
Catamaran Design Formulas
T c = 0.57. Here we put B TR = 1.9 to minimize boat resistance (for her size) and get the draft calculation for a canoe body T c (Figure 1). Midship coefficient - C m. C m = A m / T c (x) B WL. We need to estimate a few coefficients of the canoe body. where A m is the maximum cross section area of the hull (Figure 3).
Catamaran Hull Design
If you have fine hulls you can use a lower Cp. Most monohulls have a Cp of 0.55- 0.57. And that is about right for displacement speeds. However the key to Catamaran design is you need a higher Cp if you want to sail fast. So a multihull should be at least 0.61 and a heavy displacement multihull a bit higher still.
Catamaran cruising: everything you really need to know
A Code 0 can double or even triple the boat speed: in 6 knots of wind, an Outremer will sail at 2-3 knots with a jib, but 5-6 knots with a Code 0. ... Reduce sail if you start to see any more than ...
Understanding Hullspeed and the Speed/Length Ratio
The Speed/Length Ratio. S/L Ratio = hullspeed (in knots) divided by the square root of the waterline length (in feet) This discovery enabled Froude to compare the performance of boats of different length. For example a 25ft sailboat moving at 5 knots would have the same S/L Ratio at a 100ft patrol boat steaming along at 10knots, and ...
Hull speed
Hull speed or displacement speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. ... Such hull forms are commonly used by canoes, competitive rowing boats, catamarans, and fast ferries. For example, racing kayaks can exceed hull speed by more than 100% even though they do not plane.
Sailing Catamaran Speed
Measuring Catamaran Speed. Boats measure their speed in knots. Traditionally, this was measured by a tool known as a knot log. The modern equivalent is an underwater instrument with a spinning wheel that effectively measures the speed of the water passing over the hull.
The Cruising Catamaran Performance Debate
The Lagoon 450 came in at 141 versus the FP Helia 44 at 144. Interestingly the Leopard 45 came in with better numbers than the Lagoon and the FP as follows: Bruce number - 1.25; Base Speed 10.65; KSP 7.68 and TR 122. The numbers for Antares PDQ44 are very similar to the Helia 44 and Lagoon 450.
How Fast Do Catamarans Sail? Average Sailing Speed of a Catamaran
Every boat has a maximum hull speed that can't be exceeded. This can only happen in case the boat can plane on the water's surface or be lifted on hydrofoils. For most boats, the longer the boat, the higher the maximum hull speed is. Sailing catamarans typically average about 10 knots while pontoon boats average about 16 knots.
Optimising Hull Lines for Performance
A discussion about catamaran hull shapes and how they relate to performance and sea keeping with specific reference to the 33' catamaran Mad Max. ... Fine hulls are fast, but only in the higher speed range. There's a misconception I come across quite a bit that you can add weight and windage and you'll still be fast as long as your hulls ...
How fast do sailing catamarans motor?
The calculations for a catamaran are more complicated. The formula for catamaran hull speed is 1.34*(wetted length)1/2; however, this drag formula is generally not the limiting factor for catamaran hull speed. This is because boats with waterline length to beam ratios greater than 8:1 are not limited by hydrodynamic drag factors, whereas smaller boats need to plane to do so (planing requires ...
Busting the hull speed myth
That is the average speed over 2,000m for a single sculls rower in a world record time. The reason for this high speed is a half angle of entrance of less than 5º. Hobie Cats, Darts and many other catamarans have similarly low angles of entrance and reach even higher speed-length ratios with their V-shaped displacement hulls.
Catamaran
A Formula 16 beachable catamaran Powered catamaran passenger ferry at Salem, Massachusetts, United States. A catamaran (/ ˌ k æ t ə m ə ˈ r æ n /) (informally, a "cat") is a watercraft with two parallel hulls of equal size. The distance between a catamaran's hulls imparts resistance to rolling and overturning. Catamarans typically have less hull volume, smaller displacement, and ...
Advantages of Catamarans and Catamaran Hull Speeds Calculation
The formula for catamaran hull speed is 1.34*(wetted length)1/2; however, this drag formula is generally not the limiting factor for catamaran hull speed. This is because boats with waterline length to beam ratios greater than 8:1 are not limited by hydrodynamic drag factors, whereas smaller boats need to plane to do so (planing requires ...
CRUNCHING NUMBERS: A Better Way to Estimate Hull Speed
Plug 1.49 into the hull-speed formula (1.49 x √LWL) and you get a new nominal hull speed of 7.9 knots (1.49 x 5.29 = 7.88), as compared to the boat's old nominal hull speed of 7 knots (1.34 x 5.29 = 7.08). This in itself is an appreciable difference, but it grows even larger as the boat grows lighter. Assume, for example, that our 12,000 ...
Catamaran Hull Speed
87689 posts · Joined 1999. #1 · Dec 28, 2007. The hull speed formula for displacement monohulls is 1.34 x the square root of the waterline length. When planing, a monohull will exceed it's hull speed. Obviously this formula doesn't apply to catamarans. Even when not planing, they will travel much faster than what the hull speed formula predicts.
maximum hull speed for cat
Many catamarans are not limited to their hull speed. I did this with a Hobie 18 frequently. An 18 foot boat has a hull speed of 5.9 knots. I frequenty hit 20 knots and above and was not planing. You need to have a high sail area to displacement ratio, a high righting moment and narrow hulls. Catamarans do have a hull speed but it is not their ...
determining CATamaran hull speed
The concept of "hull speed" (v = 1.34 * sqrt (LWL) for waterline in feet, v in knots) assumes that the boat is essentially limited to the speed of a wave that's as long as the hull- a rough (at best) approximation for monos, and almost meaningless for cats. Your naval architect, once you find one, will have access to much more sophisticated ...
SeaRescue Catamaran
The SeaRescue Catamaran might be your new go-to project. ... 3D-printed boat isn't just about speed and stability—it's built for versatility. Whether you're retrieving an RC plane from the water or just enjoying a day at the lake, this boat gets the job done with style. Why You'll Love It: Dual-Hull Design: The twin hulls keep things ...
Abstract
Abstract. In recent years, the demand for efficient waterborne transportation has led to the development of high-speed catamarans. However, increased operating speeds result in elevated ship motions, making ride control systems desirable for passenger comfort, crew workability, and operational efficiency. This paper presents comprehensive towing tank experiments on a 2.5 m hydroelastic ...
Gunboat 57 Charter Catamaran Will Spoil You With Speed
Gunboat 57 Vai Vai is not your average charter cat. Rachel Fallon-Langdon. One of the many perks of my job as a yachting writer is that I get to sail aboard a wide variety of boats.

How Fast Do Catamarans Go? 5 Examples (With Pictures)

Average Speed For Sailing Catamarans

3 Different Types of Sailing Catamarans:

2) Cruising Catamarans

3) Racing Catamarans

Average Speed Of Power Catamarans

1) Power Cruising Catamarans

2) Swath Catamarans

3) Whitewater Catamarans

Performance Characteristics Of Catamarans

Are Catamarans Faster than Mono-Hull Vessels?

How Is The Speed Measured?

How Fast Are Catamarans Compared To Other Boat Types?

1) The hull type as listed above.

2) The length of the boat

Speed Vs. Comfort Considerations For Catamarans

The 8 Fastest Cruising Catamarans (With Speedchart)

How Fast Are Cruising Catamarans?

Factors That Impact Speed

Narrow Hulls

Light Weight Materials

Gunboat 68 (+35Kts)

Specifications

TS 42 (ORC 42)

Outremer 45

Marsaudon Composites ORC50

FastCat 435

Fountaine Pajot Astréa 42

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Catamaran Hull Design

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Yachting World

Catamaran cruising: everything you really need to know

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Sailing Catamaran Speed

Table of Contents

Speeds of Various Types of Sailing Catamarans

How fast is a catamaran?

Do catamarans have a hull speed?

What is the fastest cruising catamaran?

The Cruising Catamaran Performance Debate

Cruising Catamarans Performance

Catamaran Performance Factors & Calculations

Performance Cruising Catamarans

The Bottom Line

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