canting keel sailboat

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Headings: Canting Ballast Keels

There's no question that they work, but there are still engineering and safety issues being worked out in the upper reaches of the racing game that will take time to trickle down. it will happen, though..

When the technical management team of the Volvo Ocean Race (of which I am a member) started looking at upgrading the performance of boats for the 2005-2006 race around the world, we considered a number of options, including bigger versions of the 60-foot water-ballasted boats used for the 2001-2002 race, big multihulls, and higher-performance monohulls. Volvo finally chose a can’ting-ballast, multiple-foil 70-foot monohull with a limited amount of water ballast to adjust fore and aft trim when running downwind at high speeds in the huge seas of the Southern Ocean. 

Accepting can’ting ballast keels was a big step. These keels offer the possibility of big increases in performance, but there’s no free lunch. A can’ting ballast keel introduces significant engineering complexity and cost increases compared to a conventional fixed-ballast keel. Multiple movable appendages create potential structural weaknesses, not only in the appendages themselves, but in their support structures.

For Volvo—a company whose name is almost synonymous with safety and conservatism—adopting leading-edge technology for a class of ocean racers designed to operate at top speed in every conceivable condition was more than a leap of faith. The choice to pursue a can’ting ballast keel boat was a carefully considered decision to look to the future of performance monohull sailing. And when you look to the future, you see can’ting ballast keels staring you in the face.

The idea of the can’ting ballast keel has been around for a long time. One version of the modern can’ting keel—the patented CBTF (Canting Ballast-Twin Foil) dates back to the late 1980s, and is the direct descendant of the late Tom Blackaller’s “geek” 12-meter, built for the 1987 America’s Cup in Australia. The geek had a fixed bulb keel and a forward canard appendage, but the hydrodynamic groundwork was laid for the logical next step—a can’ting ballast keel with rudders both forward and aft of the keel.

You really have to change your mindset about sailboat design when you consider can’ting ballast boats. In the conventional fin-keel sailboat, the keel serves two functions: to contain the ballast that provides the righting moment necessary to keep the boat rightside up, and to provide an efficient lateral plane that stops the boat from sliding sideways when the force of the wind fills the sails, especially when sailing upwind. Dead downwind, the conventional keel sort of gets in the way, creating drag. Upwind, the keel creates a combination of righting moment, lift, and drag.

The can’ting ballast keel, however, cannot provide efficient lateral plane for upwind sailing. The keel fin or strut is no larger than is absolutely necessary to support the ballast bulb. When the ballast is can’ted to one side, the strut is largely ineffective in providing lateral plane. With a can’ting ballast boat, appendages other than the keel must provide the lateral resistance that both balances the driving forces of the sails, and allows you to steer the boat. A can’ting ballast keel boat, without its other appendages, would pretty much slide sideways through the water.

Here, the two most common approaches to can’ting ballast diverge. With the patented CBTF approach, centerline rudders fore and aft of the ballast package steer the boat, balance the helm, and provide the necessary lateral plane. The fore and aft rudders can operate together or individually, with different angles of attack. This creates an extremely efficient lateral plane, significantly reducing leeway when sailing upwind.

The other approach uses single or twin rudders at the aft end of the boat, and single or twin daggerboards forward of the ballast package for lateral plane and balance. With twin daggerboards and/or rudders, these appendages are angled from the perpendicular so that with the boat heeled at its optimal sailing angle, the leeward appendages are perpendicular to the surface of the water, and therefore most efficient at preventing leeway.

The downside with twin rudders and twin boards is the additional weight of a second pair of foils. The upside is a slight gain in engineering and construction simplicity compared to forward and aft rudders, particularly if only single centerline rudders and boards are used.

Open 60 monohulls often use the twin aft rudder, twin forward daggerboard approach, since rules for major events for these boats limit the static heel angle of the boats, with the ballast fully can’ted, to a mere 10 degrees. The Volvo 70 class and the new super-maxi “maxZ86” class on the other hand, control not the heel angle of the boat, but the can’ting angle of the ballast package. By allowing a greater can’ting angle—40 degrees in the case of the Volvo 70—the relatively small ballast package is far more efficient in keeping the boats upright, making them extremely powerful, particularly when reaching.

The static heel angle for a Volvo 70, with the ballast fully can’ted, will probably be greater than 25 degrees, perhaps making centerline, perpendicular appendages a reasonable alternative to reduce drag and weight. We fully expect, however, to see various configurations as different designers come to grips with the problem of designing a boat with minimal performance weaknesses, whether upwind, reaching, or running.

So far, the application of can’ting ballast keels has been primarily to ocean racing boats. Notable examples are open-class monohulls, such as the Open 60, the tiny Mini 6.5 class (about 21 ft. overall), the new Volvo 70, and the maxZ86 class.

The Schock 40, a successor to the DynaYacht Red Hornet, campaigned by Peter Isler starting in the late ’90s, is the first production racer/cruiser with a can’ting keel, and has been a pioneering boat in promoting the can’ting ballast concept.

There have also been several high-end state-of-the-art cruising boats designed with combination can’ting/lifting keels. This would be the ultimate combination for a cruising boat, which could extend the keel for maximum righting moment when sailing in the ocean, but reduce draft for coastwise cruising and shallow anchorages.

Big cruising boats fight a constant battle with weight and draft. Cruising amenities are heavy, and deep draft eliminates desirable cruising grounds. It is very difficult to create a big cruising sailboat with enough ballast-generated stability to sail upwind efficiently. The can’ting, retracting ballast keel can offer the best of both worlds in creating a high-performance cruising boat for the owner with deep pockets.

How They Work The basic principle is pretty simple. A streamlined bulb of lead is fitted at the bottom of a slender, air-foil shaped strut machined from high-strength steel, such as 17-4PH alloy. This alloy is not as corrosion-resistant as more commonly used steels such as type 316 stainless, but it is considerably stronger. High-strength, off-the-shelf sailboat hardware components such as snap shackles and padeyes are often made of 17-4PH steel, so it is not a particularly exotic material.

Just inside the hull surface, a longitudinal pivot bearing provides the axis of rotation of the keel fin. The keel strut itself extends up into the hull, where a mechanism—generally a big hydraulic ram—applies force to the top of the keel fin to push it to one side. The fin rotates about its pivot point, and the ballast bulb and the lower part of the fin are pushed or pulled to one side or the other. Think of it as a big, heavy pendulum that can be moved from side to side and fixed in any position to offset the heeling moment of the pressure of wind on the sails. The boat can be sailed flatter and faster.

Structure and Safety This sounds pretty simple, but the forces involved are huge. Substantial structure is required inside the boat to support the weight of the keel and can’ting mechanism, and the entire package has to be strong enough to withstand shock. The bulb has to remain attached to the fin, the fin has to stay attached to the can’ting mechanism, the can’ting mechanism has to stay attached to the boat, and the whole shebang has to be able to absorb the impact of grounding or collision with floating debris without tearing the boat apart.

Another engineering complexity is designing a means of sealing the point at which the movable keel strut penetrates the hull. This is one of the more proprietary sections of the design of can’ting ballast systems. Sealing the entire can’ting mechanism inside a watertight compartment in the boat is one solution, but the better solution is to prevent any water from getting into the boat in the first place by the use of a series of engineering-tolerance seals. This is not a trivial exercise.

In addition, a substantial number of safety features need to be incorporated into the system. For a Volvo 70, two separate can’ting mechanisms are required, just in case one system fails. Each system has to be engineered to the same specifications, so that they are truly redundant.

In addition, we will replicate a worst-case scenario—rig out of the boat, no power to operate the hydraulics, and the boat upside down—and require three of the crew to right the boat from full inversion from inside the boat, using only manual means such as a hand hydraulic pump to operate the can’ting mechanism and get the boat rightside up.

Needless to say, these full inversion tests will generate a lot of interest on the part of the sailing public.

Normally, a can’ting mechanism is driven by a power-operated hydraulic pump. Only hydraulics can effectively generate the type of mechanical advantage required. The hydraulic pump can either be driven directly via a power take-off on a generator or main engine, or, less efficiently, by an electric motor.

In the event of total power failure, a manual hydraulic pump—you’ll be familiar with these if you have a hydraulic vang or backstay on your boat—can drive the system, although it will take a lot longer to can’t the keel than with a powered system.

Each can’ting mechanism has to be capable of holding the ballast keel at any angle. You don’t just drive the keel out to one side and lock it off— you have to be able to hold it anyplace between vertical and fully can’ted.

Then there’s another little safety consideration: Sailing with the keel all the way out to the windward side, your resistance to capsize is very high in one direction, very low in the other. This is not a real problem in upwind sailing, because you want all the righting moment you can get on the windward side. Anyone who has ever sat on the windward rail during a race knows what this is all about.

Downwind sailing is a little trickier. A jibe and a round-down broach could catch you with the keel can’ted to the wrong side of the boat, and lay her flat in the water.

The Volvo 70s—and all other big boats with can’ting keels we have looked at—have a panic button which can almost instantly dump the keel back to the boat’s centerline, where it will then behave like a conventional ballast keel. This is much like the release valve on a common hydraulic jack, which essentially opens flow within the system, allowing it to return to equilibrium. With the keel on centerline, the boat behaves much like a conventional boat with a fixed keel, albeit with less ballast.

Another serious safety consideration is the vulnerability of forward foils to damage from floating objects. Generally, forward foils—whether daggerboards or rudders—are deep, high-aspect ratio fins, often almost as deep as the keel itself.

Compared to a conventional fixed fin keel and aft rudder combination, there is much more risk of damage associated with a forward foil. Generally, forward rudders are designed to shear off without compromising the watertight integrity of the hull, as are forward daggerboards. If you lose a forward foil, however, your ability to steer and balance the boat effectively will be significantly compromised.

For a can’ting ballast cruising boat, this problem probably leads more in the design direction of a forward daggerboard, rather than a forward rudder. A daggerboard that merely slides up and down may be easier to design with collision safety features than a more complex rudder assembly.

Weight Savings On most racing boats, the ballast keel is the single heaviest object on the boat, and makes up a large percentage of the total weight. On a performance cruising boat, the ballast keel might constitute about 40% of the weight of the boat. As an example, the 18,250-pound J/133—a modern 43-foot cruiser/racer—has a keel weighing 7,250 pounds.

On an extreme keelboat—the 80-foot America’s Cup Class is one of the most extreme examples of ballast/displacement ratio sailing today—the ballast bulb (no fin, just the bulb) might contain more than 47,000 pounds of lead out of a total weight of just over 55,000 pounds for the complete boat.

While both the angle to which the bulb can be can’ted and the length of the keel strut help determine the righting moment of a can’ting-ballast boat, a boat such as the Volvo 70 requires only about half the ballast weight with a can’ting keel as it would need in a fixed keel of the same draft to achieve the similar righting moment.

This weight savings increases the sail area to displacement ratio dramatically. A minimum displacement, minimum keel weight Volvo 70 goes about 27,600 pounds, and has a bulb weighing just over 9,900 pounds. The same boat with a fixed keel would need to weigh over 37,500 pounds, and have almost 20,000 pounds of ballast. It’s not rocket science to figure out that most of the time, the 27,000 pound boat is going to take a lot less horsepower to drive to a given speed than the 37,000 pound boat. Taken another way, for the same amount of sail area (horsepower), the lighter boat is going to be a lot quicker.

Remember, boats of this type are planing boats, so the theoretical top speed of a conventional displacement boat—about 1.34 times the square root of the waterline length in feet—simply doesn’t apply. A can’ting keel helps boats achieve higher performance by reducing total weight for a given righting moment.

Just as in racing cars, reducing weight means more speed for a given amount of horsepower.

The higher sail area to displacement ratio is particularly important in offwind sailing. Upwind, a boat’s stability will determine whether or not any more applied horsepower will produce more speed. Downwind, it ain’t necessarily so. Stability is less critical when there is little heeling moment applied to the boat, so the extra horsepower downwind can be more easily converted into speed.

Of course, the can’ting system itself adds a lot of weight to the boat. The part of the keel fin above the pivot point adds nothing to performance, but is essential to provide the lever arm to push the ballast to one side. The shorter that lever can be, the less useless weight there is inside the boat.

But a short lever arm means that more force must be applied to push the ballast to one side, just as the short arm on a see-saw requires a heavier person to achieve equilibrium with the lighter person at the end of the longer lever on the other side of the fulcrum.

The powerful hydraulics required to drive the short keel arm are heavy, and heavily loaded. Much of the development in can’ting keel mechanisms is geared towards saving weight inside the boat by shortening the upper keel lever and employing lighter, stronger, faster hydraulic systems.

This type of development is not cheap, and is highly proprietary. You will not find close-up pictures of the can’ting mechanisms of boats in the maxZ86 class and the new Volvo 70s plastered all over the sailing magazines, at least not for a while.

All we can say is that if you go on an absolutely state-of-the art can’ting keel boat, there is nothing obviously different about the inside of the boat. You will not find a massive internal structure and huge amounts of machinery intruding into the interior spaces. The entire mechanism is compact enough to fit under the floorboards, and the essential structure to support the keel and can’ting mechanism is fully integrated into the yacht’s normal structure.

This means that a can’ting keel could be incorporated into a high-performance cruising boat without compromising the space available for accommodations. Of course, you’d want to keep those accommodations as light as possible to take full advantage of the possible weight savings.

Canting keel mechanisms may be developed past infancy, but they are just barely reaching the stage of adolescence. They have reached the stage where design details are moving forward at rapid speed, just as in the development of computers. Today’s state-of-the-art may be tomorrow’s ho-hum.

Cost No one is going to claim that a can’ting keel boat is as cheap to build as a fixed-keel boat. There are a variety of can’ting mechanisms around—many protected by patents—but they are not exactly off-the-shelf items that you buy out of a marine catalog. For most of us, this means sitting on the sidelines and watching the big boys play, at least for now.

The Schock 40, however, is similar in price to other, more conventional racing boats of her size, so the time is not far off when can’ting keel boats will seem less like exotic, expensive toys, and more like mainstream options.

We can hardly wait.

You can learn more about patented CBTF technology on the internet at www.dynayacht.com . For information on the Volvo 70s, go to www.volvooceanrace.org . For information about other types of can’ting ballast boats and systems, enter “can’ting ballast keels” in an Internet search engine.

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Great article, thanks Darrell

As you say, the developments made were to make everything within the boat more compact and lighter. Were the very early models of the 1990’s in this regard over-engineered and therefore relatively safe, even if using a manual rope & winch system ? Thanks

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Sailboat Keel Types: A Complete Guide

Last Updated by

Daniel Wade

June 15, 2022

A keel is a very important part of a sailboat, crucial to its stability and ability to sail upwind. This article will discuss the fundamentals of all keels down to the details of the best keel for your boat. We will answer questions including what it does, what it's made of, and even some problems that a keel can cause. By the end of this article, you will be an expert on all things keels!

Table of contents

What Is a Keel?

A keel is the robust underwater centerline of a boat, and often extends into a long, hydrodynamically shaped blade.. It can vary in size and shape depending on the make and model of the boat. But, generally, it will look very much like a fin. If you imagine the fin on the underside of a surfboard you will have a pretty good idea of what it looks like under the boat.

It is crucial to helping with steering and control. The word keel itself comes from Norse and Dutch roots. The word simply means a structural component of the boat. You may have heard the term keel-haul, where pirates would drag someone underneath the boat across its keel. This is pretty barbaric, but it shows just how long a keel has been an important part of the boat. From Vikings to pirates to modern sailboats it has always remained an important part of a sailboat.

What is a keel made of?

A keel will typically be made of whatever the rest of the hull is made of. If the boat is wooden, it will most likely have a wooden keel. If the boat is metal, the keel will be metal, and so on. Sometimes, particularly on fiberglass boats, the core of a keel will be reinforced with lead or a similar ballast while the outside is covered with fiberglass.

The keel needs to be strong enough to withstand a lot of pressure and strain. Traditionally Viking sailing boats would have a wooden keel with some metal plating on it. Casting metal was tedious so putting it on your boat was seen as a waste. Traditional wooden sailing boats, like you would imagine pirates sailing, would also have a wooden keel. It would be made from thick hardwood like oak and could also be metal plated.

Since it is used to control the direction it must brunt the force of the change of direction. If you imagine a boat turning sharply, there will be a lot of pressure on the side that is on the outside of the turn. The hull of your boat will stand up to this pressure easily, as it is very large and very strong. The keel must be strong enough to withstand this too. The keel also can drag on the ocean floor or the boat ramp as the boat is lowered into the water. For this reason, it needs to be strong enough to hold up to the weight and pressure of the boat too. If it were made of plastic it would break every time you brought the boat in and out of the water.

What does a keel do?

The keel is there primarily for stability and guidance. The keel provides all sorts of benefits to the boat. It improves the righting moment and controls the boat’s sideways movement. The keel will also typically hold the boat’s ballast. The ballast keeps the boat weighed down and helps prevent capsizing. The ballast is typically made of lead, sand, or water.

Keels can be fixed or moveable. Some keels can be removed completely or may just retract slightly so they aren’t damaged when the boat enters or exits the water. When a boat leans to one side, because it is turning or there is strong wind/waves, the keel provides the righting moment that keeps the boat from flipping. On larger boats, it is designed to be so heavy that ig will be able to recover a boat from almost any angle of heel. Without a keel, your boat may tip too far or roll completely. On bigger ships, this can be disastrous. In its ability to prevent this alone, the keel is one of the most important parts of the ship.

Does my sailboat need a keel?

Yes, you do need a keel. Pretty much all sailboats have a keel, with exceptions for multi-hulled and/or smaller boats.  

In the case of catamarans, the very design principles that lead to the dual-hull design render the keel obsolete. The stability introduced by the outrigged, dual-hulls replaces the necessary righting moment from the keel. Because almost all the structure of a catamaran is between the two hulls, unlike a monohull which builds out from and around its centerline, there is not a lot of weight pressing out to flip the boat. Related to this, since most catamarans have the length of their hulls pressing into the water, the steering force normally placed on a keel is distributed across the length of the two hulls, which additionally will carry their own ballast.

On smaller dinghies, a small swinging centerboard or daggerboard will suffice to play the role of a keel. The centerboards can be big enough to keep the boat flowing nicely through the water without the need for a large keel. Additionally, it is not a disaster for a small sailing or racing dinghy to capsize, as they are designed to do so and recover rather easily, so the ballast from the keel is also not terribly necessary. 

If you have a motorboat you wouldn’t need a keel, unless it is a very large container ship or military vessel. The reason being that they are outboard propelled. The leg provides enough stability on its own. This is only the case with full plane powerboats. Displacement (even semi-displacement) craft will still need a keel of sorts for stability purposes.

What are some downsides to having a longer keel?

If you have a long keel that doesn’t retract or detach, you may have some problems coming in or out of the water. The keel extends far below the bottom of the boat, so if you are bringing your boat up or down a boat ramp you may find that it scrapes on the bottom. If you are not careful, you may damage the keel rather badly.

Since the keel is made of metal, wood, or fiberglass it can bear the brunt of the weight quite well. If you are putting your boat in the water and cannot retract the keel, it is a good idea to go as far into the water as possible before taking your boat off its trailer. The deeper you are in the water when the boat is released the better.

Are there any nautical traditions about the keel of the boat?

The keel is interestingly very important when it comes to boat or shipbuilding.

Traditionally, the keel is one of the first parts of the ship to be made, as the rest of the ship must sometimes be built around it. This tradition is called “laying the keel,” and is a momentous occasion. It is essentially the boat’s birthday. The boat’s age is dated from this moment, and there is also typically a celebration of sorts. This goes back to the days of seafaring exploration. The only day more important in a boat’s life is the day it is finally launched.

Can other types of boats have keels?

Yes! Many other types of boats have keels, not just sailboats. A good example would be a big shipping trawler. These trawlers are very large and need all the help they can get to stay balanced. Because of this, they often have what’s called a bar keel. This is a large rectangular piece of metal that runs along the bottom of the boat’s hull. It is very thick and heavy. The idea is that it gives the boat some more directional control when steering.

Furthermore, it helps keep the trawler balanced when out at sea in rough conditions. The extra weight keeps the boat’s center of gravity as low as possible. This makes tipping the boat almost impossible. It does slow it down a bit, but that is a small price to pay for increased safety.

Huge cargo ships also have a keel, though it is different from a bar. Their keel is known as a plate keel. It is essentially another layer of the boat under the hull. Its only purpose is added weight and protection. A plate keel runs along the centreline of the bottom plate of the ship so the weight is all concentrated in the lowest place possible. This kind of keel works similarly to how the spine of a person does. It keeps your back strong and as straight as possible.

How important is it to keep my keel clean?

It is very important to keep your keel clean, just as it is important to keep the rest of your hull clean.

For any boat kept on the water rather than hauled out every day, there is always the need to clean the hulls and keels of any barnacles and other sea growth. Barnacles not only affect your performance, but can, in the long run, greatly increase your maintenance costs if not regularly addressed. 

To do so, you have to do what is known as scraping. Scraping is the process of physically scraping off all the barnacles and other sea life that has attached itself to the underside of your boat. Many marinas offer this service, but you can do it on your own with a basic plastic paint scraper and a wetsuit. When you do this, it is key to get all the way down to the bottom of the keel and all across the hull. If you don’t scrape it off, it can start to erode your boat away over time. It can also slow you down.The barnacles and other marine life create a very rough bottom. This creates more friction and will reduce your speed more and more the worse it gets. 

It is important to check with your port authority before you start scraping. Scraping is not allowed in some places as you may introduce invasive species to the area. It depends where you have been more than where you are. If you sailed from New York to Chicago, you will be fine. If you sailed from Cuba to New York, probably not so much.

How to maintain a sailboat keel

As mentioned above, it is important to scrape your keel from time to time. While racing boats will actually do this before every day at an event, it is at least a good idea for you to do this a couple of times a season. A great time to do this is when you plan on applying that season’s bottom paint, though anytime you plan to go on your boat is a good excuse to maintain!

You may want to cut off any of the kelp and seaweed that wraps itself around the keel. This is more likely to happen if you have a fin keel. If you do find that there is a lot of kelp and seaweed wrapped around it, you will want to buy yourself a kelp cutter. Unfortunately, the only way to cut the kelp off without taking the boat out of the water is to dive in and do it yourself. It is a good idea to do this in shallow-ish water with the proper flags displayed to inform other boaters that there is someone in the water. Swimming around under your boat, even when it isn’t moving, can be dangerous.

What do I do if my keel breaks at sea?

It is very rare for keels to just break off. It is even rarer at sea. After all, what is going to break it off? The only way a keel will break off ordinarily is if you run aground.

If you should accidentally make your way into shallow waters and break your keel off it is a good idea to set sail for home. You will manage well enough in the short term but will struggle over time. You are far more likely to capsize without the keel keeping you balanced.

If you have a detachable keel it is a good idea to keep a replacement. If one breaks off, you can just install the spare one. This isn’t the easiest thing to do at sea in rough conditions, but it is possible. Make a judgment call using your common sense whether it is worth the risk or not.

Another reason your keel might break or come loose is if the keel bolts come out. These bolts are what holds the keel in place. If you happen to have a keel held on by bolts, then doing proper maintenance is even more important. If the bolts come loose, the keel can come loose.

Since the keel is typically welded on to the boat’s hull the chances of it coming off completely are slim to none. Most often, running aground on a sandbar or anything short of an incredibly rocky bottom in heavy weather will crack off a piece or severely bend the keel, which requires a major repair. If you do notice that the keel is loose, you are better off taking it back to the marina. The bolts may not come off without using some machinery, meaning you might have to take your boat out of the water. If your keel starts to rust, you may need to speak to a professional.

What are the different keel types?

Now you know what a keel is, what it does, why it is important, and how to care for one it is time to learn about the specific types of keels. Big trawlers and cargo ships have bar or plate keels, but sailboats do not. Here are the 6 different types of keels typically found on sailboats and their purposes:

The full keel is one of the most common types of the keel that you are likely to see on a sailboat. A full keel runs from end to end of the boat lengthways. A full keel, as the name implies, runs almost the entire length of the boat. At a minimum, it must run 50% of the length of the boat. A full keel is one of the most stable keel types, which is why it is so common. Full keels are also safer should you run aground. If a boat with a full keel should come ashore, it will cut its way through the sand and eventually land on its side. Whether you are grounding your boat intentionally or not, your boat will have far better odds of surviving the ordeal with a full keel.

A fin keel is similar to a full keel, just shorter. There may be one or two fin keels along the length of the boat hull. A fin keel is defined by being less than 50% the length of the boat. The fin keel works almost entirely the same way that a shark's fin does. When you wish to turn, the keel provides the resistive force that keeps you turning. This means that it essentially acts as your tires going into a turn. Whereas a full keel is essentially just a long fin, a fin keel has very different benefits. A full keel is more stable and safer overall. A fin keel is sleeker, smaller, and most importantly makes you faster. Most racing sailboats have fin keels.

A bulbed keel is very similar to a fin keel. In fact, it is possible to make a bulb keel by shaving off part of a fin keel and attaching a bulb. Once the keel has been made substantially shorter, the bulb is fitted. The bulb is shaped similarly to how a torpedo would be on a submarine. This keel works the same as a fin keel does, offering a slightly more stability without sacrificing speed. The biggest difference between a bulb and a fin keel (besides shape and length) is where they are used. Bulb keels are most commonly used in places with very shallow waters and lots of rock/shale/coral outcrops. Somewhere like the Caribbean would be the perfect place for a bulb keel. The rounded bulb bounces off the rocks and is less likely to break off. It just isn’t going to be as quick as if you used a fin keel.

The wing keel is another alternative to your standard fin keel. Just like the bulb keel, a wing keel is an extension to the standard fin keel with an extra fitting at the bottom. A wing keel is far more streamlined than a bulbed one, at the expense of being more susceptible to breaking. A wing keel looks very similar to the tail of an airplane. It works the same way, too. The water can pass by either side of the wings, allowing you to adjust your course easily. But, a wing keel does have one major problem. If you do run aground, digging out a wing keel can be very difficult. Whereas digging out a standard fin is as simple as scraping sand away from the sides of it, a wing keel must be dug out completely. The wings act like little shovels and wedge themselves into the sand. These are generally limited to higher performance racing classes.

Centerboard Keel

A centerboard keel works similarly to a fin keel but it can retract slightly. It works by having a dagger that folds out downwards. When you are sailing, the dagger protrudes outwards and offers you all the stability and balance of a fin keel. When you are in shallow water, the dagger can be retracted upwards, essentially shortening the keel temporarily. This should be done when you are sailing in shallow waters or removing the boat from the water entirely using a boat ramp. Some centerboards work on a loose hinge. When the boat is sailing along, the dagger is out and the fin works as normal. If you should bump into something though, like some shallow rocks, the hinge would push the daggerboard back inside. This stops the keel from breaking, instead, it just moves out the way. This only works if you are only just deep enough. If you are in very shallow water you would just break the centerboard off.

Canting Keel

A canting keel also works on a hinge. Instead of working end to end, it works port to starboard. When the boat turns a corner, the canting keel swings from side to side. This allows the boat to maximize its balance and speed. Eventually, this will become the norm in racing. But at the moment it is still quite experimental. The biggest downside is that the hinge works on hydraulics, and hydraulics can fail. If they should fail at sea there is very little you can do to repair them. Once they have perfected these canting keels, they will move first into the racing classes and high performance boats, then to all new cruising boats as boatbuilders improve the technology. .

Hopefully, you now have a good idea about what a sailboat keel is,how it works, why it is so important, and, of course, all the different types. Chances are, when you buy a sailboat , the keel it has is going to be at the bottom of your list of priorities. That being said, if you are planning on sailing somewhere in particular, it is a good idea to think about what keel type you are using. Replacing them doesn’t have to be expensive, but you can go a long way to saving yourself that money either way by being prepared for your home waters!

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I've personally had thousands of questions about sailing and sailboats over the years. As I learn and experience sailing, and the community, I share the answers that work and make sense to me, here on Life of Sailing.

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MODERN SAILBOAT DESIGN: Ballast Stability

At the end of our last discussion on stability we mentioned the old mono v. multihull worst-case-scenario debate re sinking to the bottom (monohull) versus capsizing on the surface (multihull). This time we’ll focus on that which drags the poor monohull to the bottom, which is, of course, its ballast. Ballast, ironically, is added to a boat to help it stay upright. As with form stability, the principle is obvious: an object is harder to up-end if a heavy weight is placed at the bottom of it. Witness the iconic inflatable punching clown. With the majority of its weight concentrated at floor level, the clown pops back upright every time you knock it down. This, of course, is exactly what you want your sailboat to do.

 Besides helping boats sink, ballast is counterproductive in another way: it makes a boat heavier and increases displacement , thus increasing resistance and decreasing speed. But this sad fact can be mitigated. The amount of ballast needed to counteract the capsizing forces of wind and wave decreases dramatically the lower it is placed in the boat. Unlike the clown, which must always have its feet on the ground, the bottom of a sailboat can reach as far down as there is water for it to float in. This is one reason why racing sailors always prefer very deep keels and why gunkholing cruisers must agonize over the question of draft. On a stock 40-foot boat, for example, the weight differential between a shoal-draft cruising keel and a deep racing keel installed on otherwise identical hulls can amount to 20% or more of the boat’s total displacement. For many, this will seem a heavy price to pay (pun intended) for shoal-draft capability.

Just as weight down low increases stability, weight up high–generally speaking, just about any weight added at or above deck level–decreases it. It is important, therefore, not to think of ballast as a discrete feature. Think instead of a boat’s total weight and how it is distributed. For example, adding one pound of weight at the masthead of a 35- to 40-foot cruising boat effectively subtracts 7 to 10 pounds of ballast from its keel. Conversely, subtracting that pound adds 7 to 10 pounds of ballast. The effects are less dramatic but are still significant when weight is redistributed closer to the boat’s center of gravity.

Aboard most cruising boats, the center of gravity is more or less about 6 inches above the waterline. Any weight subtracted above or added below this point increases the boat’s effective ballast and lowers its center of gravity. Such increases are multiplied according to the weight’s vertical distance from the center of gravity. For example, subtracting 1 pound of weight 35 feet above the center of gravity is equivalent to subtracting 35 pounds 1 foot above it. Adding 1 pound 7 feet below the center gravity is equivalent to adding 7 pounds 1 foot below it.

The bottom line (another intended pun) is that you should always strive to keep weight as low as possible, whether or not it is officially designated “ballast.” This is why racing sailors always embrace technology that dramatically reduces weight aloft, such as carbon-fiber spars and fiber rigging. It is also why cruising sailors should be more circumspect when adding weight to their rigs. Roller-furling headsails, in-mast furling mainsails, extra-heavy wire rigging, mast-mounted radomes, mast steps, and other such gear may improve a boat’s “cruise-ability,” but their cumulative weight also significantly decreases its stability.

Cruisers often store too much gear on deck, which raises a boat’s center of gravity and can make it considerably less stable

Boats that rely primarily on ballast for stability tend to be narrow and deep. In the past they also often had a great deal of deadrise in their hulls, though this is less true now. Narrow, heavily ballasted boats, particularly those with lots of deadrise, usually are tender and quickly heel to significant angles when pressed by even a moderate breeze. But this does not make them “unstable.” When pressed to extremes, they are usually more stable than stiffer boats that rely more on form stability to stay upright. Unlike form stability, which increases a boat’s initial stability, ballast stability increases what is known as ultimate or reserve stability, which is what helps a boat recover and roll upright again–just like the punching clown–after it has been knocked flat or even capsized.

Tender boats, like stiff boats, can be both comfortable and uncomfortable. Their tendency to heel easily often makes inexperienced crew feel nervous and uncomfortable, and even for experienced sailors, working at severe angles for extended periods of time can be taxing. But when the sea gets rough a tender boat normally has a smoother motion than a stiff one. It rolls to greater angles, but does so more slowly, without the vicious snapping and jerking that characterizes the motion of a stiff boat. Sailing to weather in a strong breeze a tender boat’s lee rail will be buried much of the time, and the crew on deck will get wet, but the boat will not pound as violently as a stiff boat.

For cruising sailors, the question of which sort of stability to favor when selecting a boat is a serious one. Many designs available today, of course, are relatively moderate and compromise between extremes. As a general rule, however, popular modern designs tend to be relatively light and wide with shallow bilges, and thus are more stiff than tender. Older designs from the CCA era are usually heavier, narrower, and more tender. As a general rule, coastal cruisers who expect to sail primarily in moderate conditions can, if they like, favor faster, more modern, stiffer designs. Bluewater cruisers who are more likely to encounter extreme conditions should consider whether they’d be better off in slower, more tender design with more ultimate stability.

Shifting Ballast

The most effective way to increase initial stability aboard a boat that may or may not have good form stability is to shift significant amounts of ballast to windward while sailing. This creates a lever arm that operates at a right angle to the sail plan, which increases the ballast’s effectiveness and allows a boat to carry significantly more sail.

Crews on modern planing skiffs like this 49er have to stay well outboard to keep their boats upright

This principle is seen at work on any unballasted sailing dinghy that depends primarily on crew weight to stay upright. To prevent the boat from toppling over to leeward, the crew hikes out on the windward rail. The further to windward they can get, the more sail the boat can carry, as the crew’s effective weight is increased by the longer lever arm. On modern dinghies you often see devices such as trapezes and/or hiking rails that allow crew to get as far outboard as possible. On traditional boats like Bahamian sloops and Chesapeake log canoes the crew sits out over the water on long planks that protrude from the windward rail. When the boat is tacked, the planks are moved from one side to the other, and there is a mad scramble as the crew repositions itself.

A traditional Chesapeake log canoe in action

These days ballast on larger boats can be shifted in more sophisticated ways. In one method known as water ballasting, large quantities of seawater are moved from one side of the boat to the other as it tacks. The water is shifted between dedicated tanks on the outboard edges of the hull’s interior either with a pump or by letting the water run downhill from the windward tank to the leeward tank before tacking. Water ballast augments a conventional ballast keel and is released overboard when it is not needed.

Another way to shift ballast is with a canting keel. These are struts with heavy ballast bulbs that can swing from a vertical position under a boat’s hull out to angles of up to 55 degrees. Large canting-keel monohulls 70 feet and longer have hit top speeds in excess of 30 knots, which is comparable to speeds routinely achieved by large racing catamarans. Several canting-keel boats have sailed 600 miles or more in open water in a single 24-hour period, maintaining average speeds of over 20 knots. What makes canting keels so powerful is that they shift all of a boat’s ballast to windward while keeping it well below the hull, thus greatly increasing its effectiveness. A keel capable of canting 55 degrees requires 25 to more than 60 percent less ballast than a fixed keel to support the same hull and sail plan. The result is a much lighter boat with a much higher SA/D ratio and a much lower D/L ratio.

A modern raceboat with its ballast keel canted to windward. The daggerboards rather than the keel create hydrodynamic lift

Canting keels do have their complications. When canted well to windward a keel ceases to function as a hydrodynamic foil and other foils must therefore take its place. These can be significantly smaller than the keel itself, due to the high speeds at which the boat travels. Often these auxiliary foils are daggerboards in the boat’s midsection, one on each side, with only the leeward board deployed at any given time. Or there may be a second rudder forward of the keel, often called a canard, that works in conjunction with the primary rudder to both resist leeway and steer the boat. This configuration, referred to as the Canting Ballast Twin Foil (CBTF) system , is a patented technology seen on large maxi yachts such as Roy Disney’s last Pyewacket . Centerboards and centerline daggerboards have also been used.

Another major complication is the mechanism that swings the keel back and forth. This mechanism is somewhat simpler on smaller boats, as the top of the keel, which protrudes several feet into the boat’s interior, can be pulled to either side with nothing more than a hefty tackle. On larger boats, however, the weight that must be shifted can be enormous and mechanical assistance is required. This is normally provided by large hydraulic rams and pumps powered by the boat’s main engine or a donkey engine, which must be running when the keel is moving. In all cases the pivoting keel joint in the bottom of the hull must be properly sealed and protected against flooding. Not surprisingly, dramatic failures are fairly routine.

Canting keels have also been installed on a few high-end custom performance cruisers. Examples include the Baltic 78, certain luxury performance cruisers built by Wally Yachts, and a sleek 65-foot one-off boat, Spirit of Adventure , designed by Owen Clarke Design of New Zealand for a private client. The canting keel on Spirit is also a lifting keel, as is the canting keel on the 100-foot super-maxi Maximus , a no-holds-barred racer launched back in 2005. It is unlikely however that canting keels, lifting or otherwise, will trickle down any further into the cruising-boat market. The systems are just too complex, too expensive, and potentially unreliable.

The keel on this custom cruiser, Spirit of Adventure , designed by Owen Clarke Design, both cants side-to-side and shifts up and down (Photo by Paul Todd)

Water-ballast systems, on the other hand, have proven more popular. Indeed, several small trailerable cruising boats use static water ballast as their primary ballast. On these boats the ballast tanks are low in the bilge on the boat’s centerline and are filled after the boat is launched to increase its displacement and stability. When the boat is hauled from the water, the ballast tank is emptied to reduce trailering weight. Since the ballast is never shifted, these are more appropriately termed static variable-ballast systems. Dynamic shifting-ballast systems are less common but have appeared on several performance cruising designs. These include at least one production boat, Hunter Marine’s old HC-50, which was designed to be sailed by a couple. On some other production performance cruisers it is also possible to shift water stored in the freshwater tanks from one side of the boat to the other.

Like canting keels, water-ballast systems make a boat much more complex. The ballast tanks take up interior space that could otherwise be devoted to accommodations, and they require a great deal of extra plumbing for picking up and discharging raw water and for moving it from tank to tank. Because water is not particularly dense, because ballast tanks must be located inside rather than below the main hull, and because the water ballast represents only a portion of the boat’s total ballast, water-ballast systems also do not have nearly as dramatic an effect upon performance as do canting keels.

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These are useful advice. Thanks! For quality and affordable boat ballast check out http://www.waterskiersworld.com/category-list/accessories/boat-ballast-fat-sacs-pumps.html

Found this looking for research on a short high-school presentation on how boats work. Made my head hurt with funky words. 10/10

Very helpful in analyzing where to put 500 pounds of batteries for a conversion from diesel to electronic propulsion.

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• Righting Moment Augmentation in Modern Sailing Yachts

In the last year, two major events in the Pacific Northwest crowned champions that sailed vessels utilizing a system of enhanced or assisted ballast— Team Angry Beaver won Race to Alaska aboard a canting-keel Schock 40; and the water-ballasted Riptide 41, Blue , topped the fleet of the biggest, fastest boats in a variety of conditions throughout the Van Isle 360. To help us better understand these systems, we are honored to have the help of world-renowned Pacific Northwest designer and the mind behind Blue , Paul Bieker.

Ultralight Displacement Boats (ULDBs) started making inroads into the sailing scene in the 1970s.   This was partially driven by the new cored composite structures and improved engineering methods that allowed yacht structures to be significantly lighter than they had previously been.

The first modern ULDBs that I am aware of were designed by John Spencer in New Zealand–the classic example being Infidel (renamed Ragtime ).   Incidentally, she was the first ULDB that I watched glide by us as I trimmed the blooper on a death-rolling two tonner back in the late 70s.   The Santa Cruz scene followed the Kiwi lead, with designers like Bill Lee creating boats that excelled in the California downwind classic races such as TransPac. These boats were exceedingly fast downwind but pretty slow upwind in most conditions.   As time went on, Bill Lee, George Olsen, and Carl Schumacher produced smaller ULDBs for the wider sailing public.   These boats continued the pattern of downwind strength and upwind weakness established by their predecessors (with Carl Schumacher using more powerful hull shapes to improve the situation somewhat).

Once sailors got a feel for the excitement of sailing a ULDB downwind it was a hard thing to walk away from.   The answer to making a ULDB get around a windward leeward race course in reasonable form is to design the boats with a bit more hull form stability (more beam) than early ULDBs and to sail the boats with extra crew members that are only there as moveable ballast.   Nowadays, most of the performance keelboats on the race course are sailed with a significant proportion of their crew acting as self-propelled units of ballast.

The Alternatives

Sailboats that want to go fast on an upwind/downwind course are between a rock and a hard place.   Downwind, minimum weight is the most important factor for achieving high performance and upwind righting moment (the resistance of the boat to tipping) is the most important factor.   The problem is that righting moment in a monohull keelboat comes to a large degree from ballast weight, so improving upwind performance comes with a loss downwind and vice-versa.   One solution is using additional crew as moveable ballast; the other is to use some other system for increasing righting moment without increasing the downwind weight of the boat.

There are three methods that are currently being used to increase the righting moment of ultralight boats without compromising their downwind performance: water ballast, canting keels, and side foils (hydrofoils that extend off the leeward side of the boat to provide lift and righting moment).

Water Ballast

Water ballast systems are the lowest tech solution to increasing righting moment and they are what I have the most experience with (most of the boats that I have designed since 1995 have had water ballast systems).   A water ballasted yacht has port and starboard tanks that can be filled as needed to provide righting moment when required for upwind sailing and reaching.   The tanks are always empty for downwind sailing unless the boat is being forced up onto a tighter than normal reach.   Some high performance offshore yachts also have aft centerline ballast tanks to help keep the stern down (and bow up) in heavy air downwind sailing.   Water ballast systems usually require a pump (or pumps) to fill the tanks, however the other functions (transfer from one side of the boat to the other and draining) are achieved with the help of gravity alone.   The extra power achieved with a water ballast system is significant, for instance our Riptide 41 design ( Blue ) carries 850kg (the weight of 10 people) of water ballast per side.   This increases the upwind righting moment of the boat by almost 40% without giving up any downwind performance.   Careful design allows us to do this while still passing all of the stability requirements for Category A offshore racing.   The downside of sailing a water ballast boat is that the ballast is a bit slower to move around the boat than a typical crew.   For instance, filling a tank typically takes on the order of 5 minutes and transferring water from one side of the boat takes around 20 seconds.   This puts a premium on planning ahead on the racecourse and it makes tacking a bit more cumbersome and slow than on a conventional yacht.   The upside is that you can sail with approximately half the crew as you would on a conventional ULDB designed for racing and you are significantly lighter downwind.

Water ballast also has significant advantages when cruising.   Boats are typically cruised with much fewer people than when racing.   Typical modern racer/cruisers are quite tender when shorthanded, so cruising can be a bit frustrating on windy days.   In contrast, a water ballasted boat has almost as much righting moment cruising as it does racing so sailing performance is relatively unaffected.   Another advantage is that a water ballasted boat is significantly lighter than a conventional boat when unballasted­—so speed and efficiency under power is better.

Canting Keel

The primary alternative to water ballast for giving ULDBs the power necessary to sail well upwind and reaching is canting keel systems.   The first operational canting keel yacht that I am aware of was Fiery Cross , designed and built by Jim Young after being inspired by the imaginings of L. Francis Herreshoff.   The first canting keel boat I was aware of was Red Herring , designed by David Hubbard of wing sailed catamaran fame.   The first production canting keel yacht was the Schock 40—designed and built in Southern California around 2000.   The system has become fairly common in offshore racing boats which are focused on outright speed.

Canting keel boats rely on a keel fin that is hinged at the bottom of the boat to increase the righting moment of the boat.   The keel fin extends into the hull of the boat and is attached to a device (usually a hydraulic ram) which cants it relative to the hull.   The maximum cant angle is usually on the order of 45 degrees each side of centerline.

The final alternative for providing righting moment on ULDBs is the use of foils projecting from the side of the boat and configured to provide a combination of side force and lift.   The lift reduces the effective displacement of the boat as well as providing righting moment.   The current IMOCA solo offshore racing yachts have pushed this to the point where they are effectively flying on many points of sail.   The problem with this sort of arrangement for most boats is that the lift is proportional to the square of the boat speed and most boats just don’t go fast enough to get the foil into a range of operating speeds where they are effective.   Even in large high performance yachts they are not effective at providing righting moment upwind (i.e. their effect on righting moment does not compensate for their added drag).

With the understandable challenges that come with side foils, we are typically left with two realistic options for making ULDBs perform well on reaches and upwind: water ballast and canting keels.   Of the two options, canting keels hold the most potential, especially power reaching.   On the other hand, water ballast offers relative simplicity and has the advantage that the boat is operating at a lighter weight downwind and in light air.   This makes it a reasonable choice for light air and windward/leeward sailing, which is why I have gravitated towards that solution for the boats I have designed for the Pacific Northwest.

From the February 2020 issue of 48° North

Paul Bieker

Paul Bieker is the founder and owner of Bieker Boats, which recently relocated from Seattle to Anacortes. He has designed everything from the fastest International 14s in the world to the hulls of the most recent America’s Cup multihulls, and many things in between.

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10 Types of Sailboat Keels

Explore the top 10 sailboat keel types for improved sailing, stability, & safety. Ideal for ocean voyages & shallow waters. Perfect for travelers & sailors.

Every component of a sailboat affects the cost, handling, and safety of the vessel. Perhaps none of these components are as overlooked as keels. So, how many types of sailboat keels are there and how do they differ?

The most common types of sailboat keels are bilge, bulb, and fin keels which are beloved for their speed. Full keels offer the most stability and make them best-suited for ocean sailing compared to shoal and daggerboard keels. Lifting, twin, and bilge keels are all popular as well and are known for providing a smooth ride.

Factors such as the size of your sailboat and where you intend to take it to help determine which type of keels you should consider. Some types of sailboat keels, such as full keels are great for ocean sailing whereas shoal keels are ideal for shallow waters. Follow along as we explore the 10 types of sailboat keels and see what the best practical use is for each one.

Sailboat Keel Types

Each of the types of sailboat keel is different in style, application, and ideal use. For example, fin keels are great for racing sailboats whereas shoal keels are better for cruising.  You also need to consider how far you plan to go from shore and which type of water you are sailing through .

For example, some keels can easily cut through choppy water without suffering stability. On the other hand, some sailboat keels are only suited for smooth and shallow waters. Let’s take a look at the 10 types of sailboat keels.

Canting keels are among the most practical and impressive types of sailboat keels. They come in a wide variety of sizes that are proportionate to the size of the boat in question.  Canting keels are attached to a strut underneath the boat and they are designed to extend as low as possible .

This dynamic keel isn’t fixed, so you can adjust it based on the wind and the direction of your boat. Many boaters look for this in a sailboat because it lets you react accordingly under different weather and water conditions. Ideally, you should be able to adjust a canting keel while onboard so that you can go as fast as possible.

Bilge keels refer to multiple fins that extend from the bottom of a sailboat. Neither of the 2 fins sticks out too far, so you won’t have to worry about damage when you come close to shore or sail through shallow water.  They aren’t the fasted type of keel, but they are quite easy to maintain because of their relatively small size and simple design .

Arguably the biggest benefit of bilge keels is that they offer superior roll stability. This provides a smoother ride which is essential if you sail through rough waters or easily get seasick. You will most commonly find sailboats with bilge keys in areas with shallow water around a coastline.

A bilge keel should last for years to come as long as you properly maintain it. Dry your bilge out every few months and clean it so that it continues to work well and doesn’t suffer algae damage.

Boat Design Net

Consider a sailboat with a bulb keel if you value stability and safety . Also known as wing keels, bulb keels are perfect for large sailboats and can help keep them on track. That can be difficult to do with a massive sailboat, especially in inclement weather conditions or in rough water.

A bulb keel can use its weight to balance a large or long sailboat when it shifts from one side to another. As the name suggests, bulb keels are shaped like a standard bulb, and they look almost like teardrops. They are low-maintenance as long as you can dry and clean your bulb keel’s surface every few months if you use it often.

4. Daggerboard

Practical Sailor

Daggerboards are a unique variety of keels that are removable and easy to maintain. They are easy to use for beginners and seasoned sailors alike.  However, you should only use a daggerboard keel with a small boat because it may not be strong enough to sway one that is long and heavy .

A sailboat with a daggerboard can sail up to 2 knots faster than other sailboats under the right conditions. Daggerboards make it easy to steady and balance your sailboat because you can easily adjust the boards themselves. With that said, the presence of a daggerboard can add a lot of money to the cost of a sailboat.

They can add up to $15,000 or more to the cost of a boat, especially if you get one with a dual daggerboard which offers more control. Daggerboards are also cumbersome and can reduce some of the storage space on your boat depending on which type of hull you have.

Sailboat Cruising

Your sailboat likely has a fin keel if it was made in the last 10-15 years.  Fin keels are commonly praised for being precise and fast which is useful in fresh water and saltwater . A fin sticks out of the bottom of the sailboat in the perfect shape that doesn’t reduce your sailboat’s hydrodynamic nature.

You get more speed with a fin keel than most of the alternatives because they aren’t cumbersome. Their shape is meant to easily cut through the water without any trouble. Fin keels can also easily steady a sailboat as it sways even if the waters are rough or the weather is bad.

They also appeal to beginners because fin keels make it all too easy to steer sailboats of any size . Storage isn’t a problem for sailboats with fin keels because they don’t take up too much internal space that could be used for cargo. You can find fin keels on everything from casual cruisers to professional-grade racing sailboats.

6. Full-Length

Rigging Doctor

Full-length keels are a popular alternative to fin keels, even if they are somewhat slower and less modern. With that said, sailboats with full keels make up for the lack of speed and precision with stability.  The stability that a sailboat with a full keel has to offer is unparalleled in the world of marine technology .

That is large because the keel starts at the front and continues all the way through the aft. Unlike some other varieties, full keels are a part of the hull itself. This makes them large and heavy which can limit the speed but also makes it much easier to control your sailboat.

Life of Sailing

Shoal keel sailboats are unique in that they have a limited draft which makes them perfect for drifting . However, you aren’t limited to any particular style or activity with a shoal keel unless you take your boat out far into rough waters. They aren’t as stable as full keel sailboats which put you at a higher risk of capsizing if an emergency occurs.

You wouldn’t necessarily want to take a shoal keel sailboat out for a long-distance trip. They are best suited for fun excursions that don’t take you too far from shore or into choppy waters. Even still, sailboats with shoal keels can easily handle a trip close to shore or even within shallow lagoons.

Sirius-Yachts

Twin keels are a type of bilge keel that has 2 keels and they have recently become popular again. Their rise in popularity is mainly because of their handling and how smooth they are.  You can easily make a wide turn with a sailboat equipped with a twin keel and maintain a similar speed .

Another major benefit of sailboats with twin keels is that they can stand when you bring them to shore. This makes it easy to connect your sailboat to a trailer, perform routine maintenance, and transport it. Great performance aside, this is a major selling point of twin keels because it can otherwise be difficult to maintain and transport a sailboat.

Yacht Harbor

Sailboats with quad keels particularly come in handy if you need to make several tight turns on a single trip. Quad keels are designed so that you won’t have to fight to steady your sailboat once you’ve made a turn.  Of course, you will need to adjust based on the situation, but the additional keels make it all too easy to navigate tight passages .

10. Lifting

Owen Clarke Design

Lifting keels, or swing keels, are retractable, stable, and easy to use. You can even beach a boat with a lifting keel without worrying about causing damage.  They are retractable and your boat can operate well whether your lifting keel is up or down .

You get more variety with a lifting keel than you would get with one that is in a fixed position and unable to move. Speed isn’t necessarily the main appeal of boats with lifting keels, but they are lightweight nonetheless. All that you need to do is raise or lower the keel via a lever attached to ropes or a pulley.

With that said, you need to keep an eye on several key components of your lifting keel so that it stays in good shape. Lifting keels require a system that includes a winch, turning ball, and cable which are all necessary to function. Otherwise, there aren’t any downsides to a lifting keel as long as you keep up with the maintenance.

Best Keel For Ocean Sailing

Full-length keels are the best option for ocean sailing because they are reliable. They don’t offer as much speed as a fin keel, but they are much more reliable.  Full keels are the most comfortable option for ocean sailing because of their smooth and easy-to-control nature .

You can support from a full keel throughout the majority of your sailboat’s hull. This is invaluable while ocean sailing because there will always be an element of waves and choppiness. It also doesn’t hurt that you won’t have to worry about your sailboat changing course while ocean sailing.

With that said, some boaters prefer fin keels for ocean sailing because of their speed and maneuverability. The right choice for you comes down to whether or not you want to cruise casually or enjoy a speedy journey at sea. Personally, the stability of a full keel is more appealing than the extra speed of fin keels because you need a stable vessel on the ocean.

Best Sailboat Keel For Fishing

Bilge keels and shoal keels are the best sailboat keels for fishing. They can both handle shallow waters quite well and can easily navigate tight passages.  That is often necessary when fishing, especially if you visit small coves and lagoons and need as much control as possible .

Sailboats aren’t always thought of as the best types of boats for fishing, but choosing the right keel can make a huge difference. Bilge and shoal keels both have shallow drafts which give you more control in areas where you’d be likely to stop and catch some fish. A bilge keel or shoal can make the difference between a sailboat that is suitable for fishing and one that is meant for racing and cruising.

Sailboat Keel Material

Sailboat keels are made of several types of materials, but the most common are lead and cast iron . Each of these materials is durable enough to withstand prolonged exposure to water which is unavoidable with sailboat keels. Typically, sailboat keels are made of a combination of several materials in small concentrations.

For example, many sailboat keels feature a combination of cast iron, lead, and concrete infused with iron. The mixture gives the keel stability and protects the metals from quickly corroding from water. Many boaters and enthusiasts are reasonably apprehensive about the presence of lead, but lead isn’t in every keel.

The presence of lead typically only applies to sailboat keels that have a ballast, but not all keels with ballasts even have lead .  With that said, you will find lead in many of the most popular types of sailboat keels, such as fin keels. You can typically count on the presence of cast iron, however, because it is superior to other types of iron in terms of durability.

What is an Encapsulated Keel?

Grabau International

An encapsulated keel is a keel that is part of the hull itself. You can encapsulate several different types of keels, especially if you customize a sailboat or yacht.  This will come at an extra cost, but many sailors find the money worthwhile given the added stability .

Encapsulated keels have become more common and are now often available as stock parts of new boats. The keel is molded to the hull instead of attached with hardware such as rivets. This is essential to the stability of an encapsulated keel because you won’t have to worry about hardware suffering water damage.

Can You Sail Without a Keel?

You can sail without a keel if you have a dinghy, and that is an affordable alternative to a standard sailboat.  They are tiny sailboats that don’t have a ballast or keel and measure under 20 feet long . Dinghies are safe to sail with, but you shouldn’t go out more than 1-2 miles from shore.

Otherwise, you risk losing your course because of the lack of a keel that can help keep your vessel on the right path. The further you take a boat out, the easier it is to stray from your path even with modern navigation technology.

You should never attempt to sail a boat that is over 20 feet long without a keel whether it is damaged or you removed it. This will take away much of the control that you need to safely sail whether your distance is short or long.  Your sailboat needs a keel whether it’s a monohull or multi-hull vessel if it’s over 20 feet long .

So, What Are The Types of Sailboat Keels?

The best types of sailboat keels are fin keels, full keels, and bilge keels . They all offer a great mixture of precision and maneuverability, but full keels in particular offer the most stability of them all. Bulb keels are another great option if you want a sailboat keel that is stable and safe.

However, you need to especially keep an eye on bulb keels because they can easily carry scum and algae. Lifting sailboat keels are great because they are retractable so you don’t need to worry about your approach to shore. Full keels are the most well-rounded and best suited for ocean sailing, but fin keels are the fastest and most precise.

Kit Evans is a seasoned marine journalist and naval architect, bringing over 20 years of multifaceted experience in the boating industry to his writing and consultancy work. With expertise ranging from boat design and marine surveying to charter operations and vessel restoration, Kit offers unparalleled insights into all aspects of maritime life. When he's not penning articles for top boating publications or hosting his popular YouTube channel, Kit can be found sailing his lovingly restored 1960s Columbia 29 on the Chesapeake Bay, embodying his commitment to both preserving nautical heritage and embracing modern innovations in boating.

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What does the keel do on a sailboat and how it works

• Top Questions

The water and wind act as opposing elements. The wind pushes you forward at the same time as the water resists it.

From this principal thousand of years ago, were believed that the keel was invented in the early days of sailing. and in the modern days, we start to understand what the keel does and how it works.

What the keel do simply:

provides an opposite force from the bottom of the sailboat to the force of the wind from the top to keep the sailboat balanced and not being blown sideways by the wind and it holds the ballast that keeps the boat right-side-up and prevents it from lean too much or tips over completely.

It came in different sizes and shapes from boat to boat depending on the purpose that will fulfill. without further ado let’s start from the beginning.

What is a keel?

The keel is a flat blade that comes down from the bottom-most part of a vessel in the center of the hull and it’s the longitudinal structural element on a vessel. It can vary in size and shape depending on the building process and the purpose that will serve.

The laying down of the keel is the initial step in the construction of a vessel for most shipbuilders around the world. Many refer to it as the backbone which you take literally.

All sailboats have a keel, centerboard, or daggerboard. In general speaking, on larger boats, the keel is longer, a blade-like structure extending from the hull bottom, frequently straight to the boat’s deck.

The keel is built of whatever the boat is built of—usually fiberglass, aluminum, wood, or steel—and the ballast is lead and is either bolted to the bottom of the keel or placed inside it.

Some keels can retract into the boat itself or even be removed entirely. Other keels flip upwards, You generally won’t find these on larger ships. While some can’t be budged in any direction whatsoever.

And while most keels serve the same purposes, some of them are better than others in some aspects. like speed, maneuver, and steering. but first, before we dive in, let’s see what the keel do

How does the keel works

The main purpose of a sailboat keel is to counteract sideways forces from wind and waves and keep the sailboat right-side-up in the water.

The sailboat keel also holds the boat’s ballast and prevents capsizing. Obviously, both very critical and substantial roles. In addition, the sailboat keel provides counterbalance and lift which help the boat perform better.

There is another job that a sailboat’s keel has, to control drifting. When you’re out in the water without any landmark to be seen, it’s very important that you are in the correct direction.

The keel comes into its own when the sailboat is sailing. There are many forces at work, including the structure of the vessels, sails, and the keel. The water and wind act as opposing elements.

The wind pushes you forward at the same time as the water resists it. The keel is making sure you’re not swinging and going sideways. The flat surface and its perpendicular position to the deck make it achievable.

When the wind pushes the sail in one direction, the keel goes the opposite way. The forces are matched even though the keel is smaller.

The density of the water makes up the difference. This element also supports tacking.

That is the maneuver that sailors must use if they are trying to go upwind. Instead of going in a straight path with the wind behind the boat, they zigzagged.

This action allows them to utilize the wind and water energy to create forward thrust. The reason they go back and forth is that they must drag the two forces together to keep moving.

What are the types of keels?

Keels can be fixed or moveable and may retract or be removed entirely. The two most common keels on sailboats are the full keel and the fin keel. But there are many others.

Trying to list every different type of keel available on the market is quite an undertaking. But I will cover a few of the more common types:

It is a narrow plate (of wood, metal, fiberglass, or other material) fixed to the mid-bottom of the boats projecting downward to provide lateral resistance, It”s intended both to steady the boat and to make it handy to steer and providing very little water resistance.

A fin keel is sleeker, smaller, and most importantly If you want to go fast, you’re going to want a boat with a fin keel. Most racing sailboats have fin keels. but the fin keel offers a lesser amount of stability which is something to stay aware of.

A full keel runs the length of at least 50% of the hull, ( but most of them more than 50%). The front edge curves vertically while the aft edge often connects to a rudder. it is usually fitted on blue-water sailboats.

It has much more stability compared to the smaller keels, but this makes it slower and a bit harder to maneuver in tight spaces.

The main advantages of a full keel are safe grounding and directional stability. Safe grounding means safer when you lie on hard ground. And provides a robust, stable balancing point for the hull.

And will not tip on its bow or stern when you ground. The boat will lay on the side and take less damage. the full keel provides a line of balance. Be it intentional or not, a full keel has more stability.

A boat with a full keel points well when in the water. It has good directional stability. The full keel has a longer waterline length so it controls the flowing water more than the shorter keels.

And this gives the boat greater directional stability. The full keel is one of the most common types of keels that you are likely to see on most sailboats.

Centerboard

The centerboard keel has a base keel with a dagger that rotates downward. the dagger comes through the base outwards and offers the stability and balance of a fin keel. known as a centerboard case.

The retractability allows the centerboard to be raised to operate in shallow waters. And When the water is deep, you take the dagger down and sail with a fin keel.

With the centerboard the difficulty is maintenance. As with any moving parts, problems arise. The centerboard has to be well maintained all the time.

Dagger Keel – Daggerboard

Dagger keels are a retractable centerboard used by various sailing craft. These keels are retractable and stored in their own compartment when not needed.

While other types of centerboard may pivot to retract, a dagger keel slides in a casing inserted through the center of a vessel’s hull, usually amidships. This means you can brave the shallows with ease.

Not to be confused with a daggerboard, which is entirely removable and generally found on one man vessels like catamarans. While Dagger keels are usually found in small sailing craft.

A Bilge keel is one of a pair of longitudinal plates that like fins. (one for each side of the boat). on big ships may have more than one bilge keel per side, but this is rare. projected from the sides of a ship or boat and run parallel to the center keel.

Bilge keels minimize the draft of the vessel compared to a single fin keel thus enabling it to negotiate shallower water. and provide additional stability and keep the vessel from rolling in rough waters.

They also give a boost in speed if the boat is moving windward. Bilge keels increase hydrodynamic resistance to rolling, making the vessels roll less. Bilge keels are passive stability systems.

Bilge keels are usually fitted to commercial ships and cargo ships, and some smaller boats and sailing yachts.

A “Bulb keel” is a fin keel that contains a ballast-filled bulb at the bottom, usually teardrop-shaped or torpedo.

This keel works the same as a fin keel does. but The purpose of the bulb keel is to place the ballast as low as possible, therefore gaining the maximum possible amount of leverage and thus the most righting moment. You’d typically find them on racing sailing boats.

The wing keel is a regular fin keel with small wings projecting to the sides at the bottom tip of the keel. it is another kind you’ll see on high-performance vessels.

It resembles the tail of an airplane, These little wings serve two purposes: They provide more leading-edge length and they create less drag from tip vortices.

Tip vortices directly relate to drag, and reducing these will reduce drag. Reducing drag will directly result in an increase in speed and higher performance.

The wing is another shoal alternative to the deep fin. which gives you the privilege of higher performance on deepwater and shallows.

While a wing keel may sound like the perfect solution to a sailor who is searching for a high-performance vessel with a shallow draft, the wing keel has a serious drawback.

It is the most difficult to free if you are grounded in the mud or between rocks. The wings act like shovels and wedge themself into the ground. and freeing out a wing keel can be very difficult.

Canting keel

The canting keel mounts on a hinge, suspended from a rigid canting strut beneath the boat, which can be swung to the windward of the boat under sailing. when the boat heels, racers hydraulically rotate the keel to windward. Rotating the keel away from your healing direction generates a force that both rights the boat and propels her forward. the canting keel handling the ballast functions, lateral resistance, and the steering can be managed separately using such as daggerboards.

The main purpose of the canting keel is to allow the boat to sail closer to a level that generates maximum balance and speed. this keel best suited for racing sailboats. It is the future for racing but not perfected yet.

The downside is the maintenance and complexity associated with the canting keel, hydraulics, and other moving parts. but one day it will become the norm in the future of boat racing.

The first patent for a canting keel device was granted by Douglas Beardy on May 8, 1900.

The skeg is an aftward extension of the keel intended to keep the boat moving straight and to protect the propeller ( inbound or outbound engine ) and rudder from anything beneath the surface of the water that could cause damage to them.

A powerboat often has a skeg only on the hull which serves the same purpose.

The idea is that it will protect the prop from any floating objects in the water before it can get to it. and If it gets damaged, the vessel will have a tangible wobble when underway.

Sailing is a challenge and fun . Sailors constantly adjust sails, boat position, and onboard weight to find the perfect balance between winds, tides, currents, and boat characteristics and use these components to get the highest performance of the boat in the safest-efficient possible manner.

The keel is a fantastic piece of the sailing mechanism that many people don’t give a second thought. It needs care and maintenance from time to time.

Because most new sailors think the keel’s there just for ballast, and without the sailboat keel the Modern sailing would never have progressed to the point that it has.

you can read this article ( When was sailing invented? ) .

But now you know better. and If anyone asks you, what is a keel on a boat, you can say it is its backbone. It’s really a wing, flying under your boat .

Sailboat Keel Types: A Comprehensive Guide

by Emma Sullivan | Jul 25, 2023 | Sailboat Maintenance

Short Answer: Sailboat Keel Types

There are several types of sailboat keels, including full keel, fin keel, wing keel, bulb keel, and daggerboard. Each type provides different characteristics in terms of stability, maneuverability, and performance. Sailors choose the keel type based on their sailing preferences and intended usage of the boat.

Understanding Sailboat Keel Types: A Comprehensive Guide

As any avid sailor can testify, understanding the different sailboat keel types is paramount to a successful and pleasurable sailing experience. A sailboat’s keel acts as its foundation, providing stability, preventing sideways drift, and enhancing overall performance. With various keel options available in the market, it can be quite overwhelming for newcomers or even seasoned sailors to grasp the nuances of each type.

In this comprehensive guide, we aim to unravel the mystery surrounding sailboat keels. From traditional full keels to modern fin keels and everything in between, let’s embark on a journey through their characteristics, advantages, disadvantages, and their impact on sailing dynamics.

1. Full Keel:

Let’s start with the old-school favorite – the full keel. As its name suggests, this keel extends from bow to stern and offers exceptional stability due to its large surface area below the waterline. The long length also promotes tracking ability – keeping your boat moving in a straight line without much effort. Although typically found on older vessels or those designed for long-distance cruising rather than racing, full keels excel in handling heavy weather conditions and provide an overall smooth ride through choppy waters.

However, there is a trade-off when it comes to maneuverability. The deep draft can restrict access to shallower areas and make tacking (changing direction by turning into the wind) more demanding. Additionally, due to their shape and size, full keels may sacrifice some speed potential compared to their sleeker counterparts.

2. Fin Keel:

Enter modernity – the fin keel revolutionized sailing dynamics when it was introduced decades ago and remains one of today’s most popular choices among sailors seeking performance-oriented vessels. This relatively narrow (or “fin-like”) appendage protrudes deep below the hull and serves as both a counterbalance against sideways forces and a pivot point for agile maneuvers.

The fin keel’s streamlined design offers enhanced speed, better upwind capabilities, and improved responsiveness. Sailors planning to participate in racing events or seeking a thrill-seeking sailing experience often favor this type of keel. Moreover, the reduced draft allows for access to shallower waters – perfect for exploring coves or venturing closer to shore.

However, it’s essential to recognize that while fin keels excel in speed and maneuverability, stability can be compromised. A narrow base may result in more heel (tilting) when exposed to strong crosswinds, demanding careful attention from sailors. Furthermore, grounding risks are higher due to the shallower depth.

3. Winged Keel:

For those looking for a middle ground between full keels and fin keels, winged keels provide an intriguing compromise. Originating from the America’s Cup yacht races during the 1980s and 1990s, these unique designs feature additional horizontal wings near the bottom of the main keel shaft.

Their purpose? To improve stability by effectively increasing the lateral surface area without significantly increasing draft. This innovative approach enhances windward performance while maintaining maneuverability and reducing heeling.

4. Bulb Keel:

The bulb keel is another darling of modern sailboat design – especially prevalent among cruising boats aiming for optimal balance between cruising comfort and performance capabilities. These keels utilize a large torpedo-shaped bulb at their base, which concentrates weight lower down for increased stability while reducing overall drag.

Bulb keels offer excellent upwind performance, advanced tracking ability, and minimal lateral movement when navigating waves or choppy seas – all qualities keenly sought after by bluewater cruisers or liveaboard sailors longing for long voyages with maximum safety and comfort.

5. Swing Keel/Centreboard:

Now let’s discuss something adaptable – swing keels (also known as centerboards). This versatile option provides flexibility in both deep water sailing and shallow anchorage areas. Swing keels can be raised or lowered as needed, allowing sailors to decrease draft in shoal waters and subsequently improve maneuverability, while also providing deeper draw for enhanced upwind performance on open seas.

The ability to retract the keel provides opportunities for exploring hidden bays, rivers, or other areas inaccessible to boats with fixed keels. However, this convenience comes with a downside. The mechanism required for raising and lowering the keel may add weight to the boat and increase maintenance requirements.

To conclude, understanding sailboat keel types is crucial when choosing a vessel that aligns with your sailing goals and needs. Whether you prioritize stability, speed, maneuverability, or versatility depends on where and how you envision your nautical adventures unfolding. We hope this comprehensive guide has shed light on the various options available in their witty and clever explanations – setting you on a course towards well-informed decision making when it comes to sailboat keels.

Choosing the Right Sailboat Keel Type for Your Needs: Step-by-Step Process

Purchasing a sailboat is an exciting venture, but it can also be quite overwhelming when faced with the multitude of options available. One crucial decision to make is selecting the right keel type for your sailing needs. The keel plays a vital role in determining the stability, performance, and maneuverability of your sailboat. Hence, understanding the various keel types and their features will help you make an informed decision. In this blog post, we will take you through a step-by-step process to choose the ideal sailboat keel type tailored to your specific requirements.

Step 1: Assess Your Sailing Goals Before delving into technical details, it’s important to assess your sailing goals and preferences. Are you looking for a vessel suitable for racing or one geared towards leisurely family outings? Do you plan on venturing into shallow waters or embarking on long offshore trips? Determining your primary sailing objectives will provide essential insights that shape your keel choice.

Step 2: Understand Different Keel Types Next, let’s explore the common types of sailboat keels:

1. Fin Keel: Also called a modern fin keel with a bulb, this design offers excellent performance and stability even in strong winds. It reduces drag significantly due to its sleek profile while enabling better upwind pointing ability.

2. Full Keel: A traditional full keel provides exceptional directional stability but may compromise maneuverability. Ideal for offshore cruising, it offers reduced rolling motion and enhanced safety during heavy weather conditions.

3. Wing/Daggerboard Keel: This versatile configuration combines aspects of both fixed keels and centerboards/daggerboards by retracting partially or completely when needed. This allows maximum flexibility when navigating shallow waters or adjusting for varying wind conditions.

4. Bilge Keel: Employed mainly in smaller boats, bilge keels consist of two shorter keel sections placed on either side of the hull. This design enhances stability at rest and allows for grounding without damage.

Step 3: Assess Pros and Cons Now that you understand the different keel types, it’s time to evaluate their pros and cons based on your sailing objectives:

– Fin Keel: Pros: Excellent upwind performance, great stability, higher speed potential. Cons: Vulnerable in shallow waters, reduced directional stability when not under sail.

– Full Keel: Pros: Superior directional stability, excellent resistance to leeway (sideways movement), better roll dampening in heavy conditions. Cons: Lower maneuverability in tight spaces or strong winds, reduced speed potential.

– Wing/Daggerboard Keel: Pros: Versatile and adaptable to changing conditions, improved windward performance when centerboard is down. Cons: Higher maintenance requirements compared to fixed keels.

– Bilge Keel: Pros: Enhanced stability at rest, shallow draft capability for exploring shallower waterways. Cons: Reduced pointing ability and performance, may experience more leeway compared to other keels.

Step 4: Seek Expert Advice If you’re still unsure about which keel type aligns best with your needs after assessing the pros and cons, consider reaching out to a knowledgeable yacht broker or marine expert. Their expertise can assist you in making an informed decision based on factors such as boat size, intended usage area (inland lakes vs. open ocean), and personal preferences.

Step 5: Test Sailboats & Consider Trade-offs Once you have narrowed down your options based on previous steps’ evaluation criteria, take the opportunity to test-sail different boats embodying varying keel configurations. Experiencing firsthand how each sailboat handles will give you valuable insights into their capabilities and limitations. Consider trade-offs regarding aspects like speed versus maneuverability or comfort versus stability before making your final decision.

In conclusion, selecting the correct sailboat keel type requires careful consideration and an understanding of your sailing goals. By following this step-by-step process, you’ll be equipped with the knowledge needed to choose a sailboat that perfectly aligns with your needs. Remember, there’s no one-size-fits-all answer – it’s about finding the ideal balance between performance, stability, maneuverability, and suitability for your intended purpose.

Exploring Different Sailboat Keel Designs: A Closer Look at the Options

When it comes to sailing, the design of a sailboat’s keel plays a critical role in its performance and overall handling. A well-designed keel can greatly enhance a boat’s stability, maneuverability, and efficiency on the water. With various options available in the market, it’s important to understand the differences and benefits associated with each type of sailboat keel design.

One commonly found keel design is the full keel. As its name suggests, this type extends from the bow to the stern, providing extensive support and stability to the boat. Full keels are known for their ability to track straight in rough conditions and offer excellent resistance against sideways forces such as wind or waves. This makes them well-suited for long-distance cruising and offshore sailing adventures. Additionally, full keels often have a shallower draft which allows access to more shallow waters, making them versatile for exploring coastal areas.

On the other end of the spectrum is the fin keel design. Unlike full keels, fin keels are shorter and narrower, located primarily beneath the boat’s center of gravity. This leads to improved maneuverability and allows sailors to make tighter turns more easily. Fin keels also tend to have a deeper draft which provides better upwind performance by reducing side slippage while maintaining stability.

A variant of fin keels is bulbous or winged-keels. These designs feature weighted bulbs at their lower ends, enhancing stability while still allowing for efficient upwind sailing. The added weight at the bottom reduces heeling angles during strong winds while optimizing lift characteristics under sails.

For those seeking enhanced speed capabilities with reduced drag underwater, there are high-performance sailboats that incorporate daggerboard or centerboard designs. Daggerboards slide vertically through slots on either side of a boat’s hull when deployed during sailing operations but can be retracted when not needed. They offer tremendous flexibility due to adjustable positions based on wind conditions—providing sailors an opportunity to optimize lift and reduce drag accordingly. This keel design is often favored by competitive racers who prioritize speed and agility over stability.

Lastly, a popular modern innovation is the canting keel. This keel design consists of a fin that can swing out to either side of the boat via a mechanism controlled by hydraulics or other means. The ability to adjust the angle of the keel allows for advanced maneuvering and optimizing performance based on current conditions. Canting keels are commonly found in high-performance racing yachts where every degree counts in gaining a competitive edge.

When deciding on the most suitable sailboat keel design, it ultimately depends on your intended use, sailing goals, and personal preferences. Cruisers may lean towards full or bulbous keels for their stability and versatility, whereas racers seek the swift performance offered by fin or daggerboard designs.

Whichever sailboat keel design you choose, understanding its characteristics and how it aligns with your sailing objectives is vital. Consulting with experienced sailors or marine professionals can help you make an informed decision when selecting your dream sailboat—a vessel that will carry you gracefully through all your aquatic adventures.

Frequently Asked Questions about Sailboat Keel Types: Get Answers Here!

Welcome to our blog where we aim to satisfy your curiosity about sailboat keel types! Whether you’re a seasoned sailor or just getting started in the world of sailing, understanding the different keel designs is crucial for optimizing your boat’s performance on the water. In this article, we’ve compiled some frequently asked questions to provide you with comprehensive answers and shed light on this important aspect of sailboats. So let’s dive in!

1. What is a sailboat keel? A sailboat keel refers to the underwater structure attached at the bottom of the hull that provides stability and prevents excessive sideways drift. It essentially acts as a counterbalance against wind forces acting on the sails, allowing the boat to maintain an upright position.

2. How does a sailboat keel work? The primary function of a keel is to create lift in the water as it moves through it. This lift opposes and balances the lateral forces generated by wind pressure on sails, keeping the boat from being pushed sideways or capsizing. Additionally, by increasing drag and resistance, it also helps prevent excessive speed or slipping sideways when sailing upwind.

3. What are different types of sailboat keels? There are various sailboat keel designs tailored for specific purposes:

– Fin Keel: The fin keel is one of the most common types characterized by its long, narrow shape extending vertically downwards into the water beneath the boat. It offers excellent upwind performance while minimizing drag, making it ideal for racing or competitive sailing.

– Wing Keel: A wing keel features two smaller fins (wings) positioned near its base instead of one central fin like traditional fin keels. This design aims to improve stability while reducing draft depth, enabling boats to navigate shallower waters without sacrificing performance.

– Bulb Keel: Bulb keels have an additional weighted bulb located at their lower end designed to enhance stability and reduce drag even further. These keels are often found on performance cruisers or racing yachts, offering enhanced righting moments and improved overall sailing performance.

– Full Keel: On the other end of the spectrum, full keels extend along the entire length of the boat’s bottom. They provide excellent stability but tend to sacrifice maneuverability and speed in favor of increased seaworthiness, making them well-suited for long-range cruising or bluewater sailing.

4. Which sailboat keel type is best for me? The ideal keel type depends on your specific sailing needs and preferences. If you’re primarily focused on racing or want a higher level of maneuverability, a fin keel with a bulb might be more suitable. However, if you prioritize stability and plan to embark on extended journeys or offshore passages, a full keel could be an excellent choice.

5. Can I modify my sailboat’s keel? Modifying a sailboat’s keel is generally not recommended as it can significantly alter the vessel’s balance and stability characteristics. Unless you have extensive knowledge and expertise in naval architecture, it’s best to consult with professionals before considering any modifications.

We hope this FAQ section has answered some burning questions about sailboat keels! Choosing the right type for your vessel will greatly impact your sailing experience, so take the time to research and understand each design’s advantages and limitations. Whether you’re aiming for speed, stability, or versatility – happy sailing!

Benefits and Drawbacks of Various Sailboat Keel Types: What to Consider

When it comes to choosing the perfect sailboat for your seafaring adventures, one important factor that often gets overlooked is the type of keel. A sailboat’s keel plays a crucial role in stability and maneuverability, making it essential to carefully consider the benefits and drawbacks of various keel types before making a decision. In this blog post, we will explore these different types and help you understand what factors should be considered.

1. Fin Keel: Fin keels are among the most common types found on modern sailboats. They feature a deep, narrow profile that extends vertically from the hull’s bottom. One significant benefit of fin keels is their excellent upwind performance due to their low drag and efficient water flow around them. This allows for better pointing ability and higher speeds when sailing close to the wind. However, fin keels also have some drawbacks worth considering. Due to their depth, they may limit access to shallower waters and make grounding more hazardous. Additionally, their narrow profile can result in reduced stability compared to other keel types in rough conditions or during sudden gusts of wind.

2. Wing Keel: Wing keels are designed similarly to fin keels but have two small wings extending horizontally from either side of the main fin. These wings increase the overall surface area of the keel, providing additional lift and improved stability compared to fin keels. One significant benefit of wing keels is their ability to handle shallow waters more effectively than other types without compromising performance significantly. The extra surface area also helps minimize leeway or sideways drift when sailing downwind. Despite these advantages, wing keels may present some trade-offs. The enlarged wings can induce additional drag, slightly reducing speed potential in certain conditions such as upwind sailing or going against a strong current.

3. Centerboard or Swing Keel: Centerboards or swing keels offer versatility by providing both draft adjustability and easy access to shallow waters. These keels are retractable, allowing them to be raised when navigating in shallow areas and lowered for enhanced stability in deeper waters. The main benefit of a centerboard keel is the ability to explore more secluded areas that may be inaccessible with fixed keels. They also offer better windward performance than wing or fin keels when fully deployed. However, the design limitations of centerboards can result in reduced overall lateral stability compared to fixed keels. Additionally, the mechanism used for raising and lowering the centerboard can be prone to maintenance issues or potential failure if not properly maintained.

4. Full Keel: Full keels, also known as long keels, are characterized by their extended length from bow to stern. This type provides optimal directional stability and contributes greatly to reducing leeway and weather helm even in challenging conditions. One of the primary benefits of full keels is their seaworthiness and ability to maintain course easily while cruising offshore. They tend to track well and inspire confidence in rough seas. Nevertheless, full keels have some drawbacks that should be considered. Due to their larger surface area, they generate more drag than other types of keels. This additional resistance can slightly reduce speed potential, especially in light winds or when sailing against strong currents.

In conclusion, choosing the right sailboat keel type is a critical decision that requires careful consideration based on your desired sailing conditions and preferences. Each type comes with its own set of benefits and drawbacks that need evaluation depending on factors such as intended use, cruising grounds, draft requirements, and personal skill level. By understanding these nuances and making an informed choice, you can ensure an enjoyable and safe sailing experience on whichever sailboat you ultimately decide upon.

Beginners’ Guide to Sailboat Keel Types: Everything You Need to Know

Welcome aboard to our Beginners’ Guide to Sailboat Keel Types: Everything You Need to Know! Whether you’re a novice sailor or an experienced mariner looking to brush up on your knowledge, understanding sailboat keel types is essential for enjoying a smooth sailing experience. So hoist the sails and let’s dive in!

Keels play a crucial role in stabilizing sailboats by counteracting the force of wind pushing against the sails. The right keel type ensures optimal stability, maneuverability, and overall performance under various conditions. Let’s explore some of the most common sailboat keel types you’ll encounter on your seafaring adventures:

1. Full Keel: Picture yourself cruising on a classic yacht from a bygone era – chances are it has a full keel. This traditional design encompasses a long, deep fin that extends from bow to stern, providing excellent directional stability. Full keels are ideal for longer voyages as their heavy displacement reduces rolling motion, making them resilient in rough seas.

2. Fin Keel: On the flip side of the spectrum lies the fin keel – sleek, modern, and agile. Fin keels feature a shorter but more slender profile compared to full keels, extending from just below the hull near the bow and terminating towards the stern. Their reduced surface area allows for increased speed through water while facilitating easy maneuvering and quick responsiveness.

3. Wing Keel: Imagine having wings underwater – that’s precisely what you’ll find with wing keels! These innovative designs incorporate additional extensions (wings) on either side of the main fin, increasing lateral resistance as well as stability. Wing keels offer superb shallow-water cruising capabilities, allowing sailors to explore coastal areas with ease.

4. Bulb Keel: Don’t be fooled by their name; bulb keels are anything but dull! Often seen on high-performance racing yachts or larger cruisers aiming for speed, this keel type features a lead bulb at the tip of a narrow fin. The added weight significantly lowers the boat’s center of gravity, enhancing stability and reducing heeling (sideways tilting) when harnessing strong winds.

5. Bilge Keel: If you’re looking for versatility, bilge keels are your go-to option! As the name suggests, these twin keels are positioned symmetrically on each side of the sailboat’s hull. Bilge keels provide great stability both underway and at rest while also enabling easy beaching or grounding in tidal areas. Their unique design allows for exploring shallow waters without compromising maneuverability.

As with any sailing endeavor, it’s important to remember that each sailboat keel type comes with its own set of trade-offs. Factors such as sailing conditions, intended use (racing vs. cruising), and personal preference will ultimately guide your choice.

So there you have it – a comprehensive overview of sailboat keel types to set your seafaring journey on the right course! Whether you opt for the classic elegance of a full keel or the nimble agility of a fin keel, understanding these different types empowers you to choose wisely based on your specific needs and aspirations as a sailor.

Now, all that’s left is to chart your course and let the wind fill your sails as you embark on countless exciting adventures across vast oceans or tranquil lakes. Happy sailing!

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The new Farr 11s represents the culmination of intense discussions with the client, who previously owned a Farr 36 One Design. The carefully prepared brief called for an inshore boat with sufficient freeboard for coastal race capability, legs out hiking and minimal interior. The goal was to produce a very fast boat keelboat for its size (35 to 38 ft) crewed by no more than 6 or 7 intermediate level sailors. Racing venues included Key West, the Great Lakes and a variety of other regattas.

There has been considerable interest world wide in a mono hull that fits this vision and there are a number of examples similar to this style of boat. The acceptance of canting keel technology and the incredible outright speed of the VO 70's and Open 60's has opened many sailors' minds to new frontiers of high performance monohull sailing.

The challenge was to incorporate as many go fast features as possible while staying within sensible limits of price, ease of operation, and meeting safety standards of category 3 Offshore Special Regulations including stability and fit out requirements. The obvious goals are to provide high stability to carry a powerful sail plan, keep the whole package as light as possible, reduce drag, and produce a boat that will break out into high speeds in a controllable manner. These goals are blended with the desire to be a good all rounder for buoys races in a wide range of wind speeds, good in coastal type races where reaching performance and handling are important, and avoid any glaring weaknesses that are seen in some attempts at this concept.

The Farr 11s has a 45-degree canting keel, twin asymmetric canards and twin retractable rudders on a hull with high form stability. This combination has been explored in our Open 60, VO70, Cookson 50 and Leopard 3 research work and this project presented fertile ground to draw from our experience. The hull shape combines the demands for minimizing light air (low speed) drag with high-speed stability and excellent handling qualities. Twin rudders will help control in extreme conditions.

The rig is a transplant from skiff rig development with a large square-headed main on a highly swept spreader, no backstay rig. The concept should provide some automatic de powering, and minimize demands on the crew during maneuvers to leave hands available for canard operation, keel activation and sail handling. The retractable bowsprit stretches the sail plan to allow ample downwind sail area in the form of asymmetric spinnakers.

Construction is in carbon skin honeycomb core sandwich, with carbon keel fin, and an all up weight of 2400 Kg. Motoring power comes from an 20 HP outboard that is retractable in a well that opens to the cockpit. The keel is activated by a hydraulic ram/electric pump system.

The boat is being built by Premier Composite Technologies in Dubai who have received ongoing orders. Hull #1 is due to launch in Dubai in February 2007. The design team has been thoroughly engrossed by this project and is pleading for crew spots on this exciting boat.

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FREQUENTLY ASKED QUESTIONS

Why twin rudder and twin canards?

The choice of twin canards and twin rudders is ultimately linked to the beam of the boat. The wider the hull, the more the centerline area lifts up out of the water as it heels.  With wide boats the efficiency of a centerline appendage (rudder, dagger board, or canard) is quickly reduced when the root of that foil reaches the surface of the water.  The more heel the boat achieves the worse the appendage performs.  Even if the top of the appendage is fully immersed at typical heel angles, there can be a time when the boat "over-heels" exposing the appendage top.  Twin rudders or canards typically have a further advantage in that they will actually be immersed further with heel.  As a result of this immersion twin aft rudders typically have more rudder control with increasing heel angle. Twin canards also allow the designer to pursue asymmetrically cambered foil shapes, which result in a larger effective span for a given amount of wetted surface area.

Why not use a steerable bow rudder?

In addition to the reasons listed above in the section "Why twin rudder and twin canards" the forward appendage (rudder, canard, etc.) wants to be lifted when reaching and running to produce the greatest efficiency.   In summary, a configuration using twin canards combined with twin rudders produces a relatively simple configuration that maximizes efficiency and ensures the boat can be handled more easily when sailing near the limit of control.

How is canard handling envisioned for tacks and gybes?

When sailing downwind, the canards would not be needed and would both be up.  When sailing upwind and tacking, the windward canard is lowered as the tack is initiated.  The boat is tacked with both canards in the down position.  After the tack is completed, the new windward canard is pulled up. Because the windward canard is not fully immersed and because it will effectively be cambered in the "wrong" direction it will be producing relatively little side force making it easily moveable by hand.

Are they lifted / lowered by hand or by mechanical means?

During typical controlled tack and gybe maneuvers the canard can be moved by hand as described above. In steady state sailing conditions when it is desirable to move the canard under load, the force to move the canard will be too large to allow simple hand adjustment. In that case the control lines have been positioned such that the free windward primary winch may be used.

What is the total board 'throw'?

The total range of canard throw is 2 meters.

What is the expected crew size / weight?

The client's requirements for this design indicated a crew of 6 plus a guest, combining for an average total crew weight of 590kg. There will certainly be conditions where more total crew weight will produce improved results.

Is the heel still expected to be significant given the canting keel and crew weight?

The VPP work completed for this design indicates typical upwind heel angles of approximately 15 degrees. In way of reference, a larger canting keel boat typically operates with average upwind heel angles of around 20 degrees, while fixed keel yachts typically heel a bit more again, around an average of 23 degrees upwind. Optimum upwind heel angles are produced in a VPP by balancing a boat near maximum righting moment while maintaining the sailplan's maximum efficiency. A lower optimum heel angle indicates a boat whose maximum righting moment arrives relatively earlier.

Why so much bow rake and not a plumb bow like most modern designs?

The plumb or relatively upright stem angle's typical of today's boats are a product of fashion that has aligned itself with the common box rule type race boats we wish to emulate. When unconstrained by rules, designers are free to look for advantages in alternative concepts. In the case of this boat two major areas have pushed us in the direction of a more angled stem. The first is the desire to tack a removable masthead genoa forward of the forestay. This sail would be used in light air when racing under handicap systems that do not unfavorably treat such a sail. When sizing that masthead sail the resulting foot length positioned its tack well forward of the forestay requiring some form of structure to support it. The structure alone could have been provided by some other means like a portion of fixed bowsprit tube. When looking at the required structure we considered that a section of extended bow slope could also provide an added volume and flare to the topsides forward. The reserve buoyancy in that added geometry will be a benefit in waves and high speed running conditions where nose diving can be a concern. When discussing these possibilities with our client we decided together to pursue the less fashionable but perhaps more technically correct solution.

11.18 m/36.68 ft

10.00 m/32.81 ft

3.281 m/11.25 ft

2.70 m/8.86 ft

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13.15 m/43.15 ft

3.55 m/11.65 ft

15.22 m/49.94 ft

5.71 m/18.73 ft

16.72 m/54.86 ft

6.33 m/20.77 ft

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Sailboat Keel Depth: Draft of 9 Common Keel Types

Most sailboats have one of three drafts, based on their keel type. Inland water boats using centerboards have the least draft, while bluewater boat keels run much deeper.

The depth of sailboat keels depends on their design. Boats designed for inland waters usually have a draft of around 0.6m (or 2ft). Bluewater boats can either use a full keel or fin keel. Full keels run on average around 1m (or 3ft) deep. Fin keels, wing keels, and bulb keels run on average 1.8m (or 6ft) deep.

Below, I'll go over each keel type's depth and also show the range of depth based on different boat lengths, both in metric and imperial.

Draft of 9 Most Common Keel Designs

The average depth of different keel types is not readily available on the internet. To find these numbers, I've measured dozens of technical scale drawings of yachts in an old Dutch sailing book published in 1977. The numbers are quite consistent.

In order to keep things simple, I'll go over the rough averages first, before diving into a bit more detail based on boat length. After that, I'll discuss why different keel designs use different depths.

Average depths based on keel type

• Full keel : 0.8m or 3ft
• Modified full keel : 1.2m or 4ft
• Fin keel : 1.8m or 6ft
• Bulb keel : 1.8m or 6ft
• Wing keel : 1.8m or 6ft
• Bilge keel : 0.6m or 2ft
• Daggerboard : 0.6m or 2ft
• Centerboard : 1m or 3ft
• Leeboards : 0m or 0ft
• Canting keel : 5m or 16ft

Keel depths for different boat lengths

Keel Depth Explained

Different keel designs use different depths due to several factors. Fin keels are by far the longest keels, as they use their length to increase the leverage of the ballast. Full keels , on the other hand, require less depth since they carry more ballast and provide more wetted surface, which improves directional stability in itself.

Centerboards and daggerboards are often used in sailboat designs meant for use in inland waters, which is why they run on average less deep, with the daggerboard running the least deep of both at around 60cm or 2ft.

Bilge keels also run less deep, as this design was intended for use in tidal waters, and allows for safe beaching of the boat. The use of two blades instead of one doubles the wetted surface and ballast, allowing for a shoal draft.

Shoal draft simply means the keel doesn't run deep.

How deep should a keel be?

A keel should be deep enough to provide enough wetted surface and enough leverage for the ballast to provide adequate righting moment for the used sail area, while simultaneously allowing access to desired waters.

Righting moment is the most important function of a keel .

For bluewater conditions, the keel tends to be at least 1 meter deep, in order to cut through the surface drift layer of the water.

The water's surface drift layer is the layer of water directly affected by the wind.

For most inland-water sailboats, this translated to a keel depth of between 0.5-1m. For offshore boats, keels tend to be deeper, at 1-1.8m.

Factors that affect keel depth:

• Keel design
• Ballast weight
• Desired sail area
• Usage conditions (inland, offshore, cruising, racing)

How keel design affects keel depth requirement

Keel design plays a major role in the amount of ballast required and the total weight of a sailboat keel .

Full keels span over a longer area fore to aft, which is why they can be less deep while achieving the same amount of wetted surface. They also carry more ballast, which provides similar or more righting moment at lower depths than fin keels.

Since fin keels are generally quite narrow, they need to run deeper to achieve the same amount of wetted surface and to provide a similar righting moment. However, since the ballast is further away from the hull, they can carry less ballast, making the boat lighter overall (and thus faster).

How hull width affects keel depth requirement

How is keel depth measured.

Keel depth is measured vertically from the waterline, which is where the hull touches the water, down to the lowest point of the keel. Keel depth is also called draft or draught.

What is the difference between draft and depth?

Depth is measured from the top of the keel to the top of the deck beam, at the center of its length. It refers to hull depth, as opposed to draft. Draft is measured from the center point at the waterline, down to the lowest point of the keel. It refers to the minimum water depth a boat requires.

When calculating minimum water depth, you want to take your boat's draft , not your boat's depth.

What is depth below keel?

Depth below keel, sometimes called keel offset, or depth below transducer, is the distance between the lowest point of the boat and the ocean floor. It is measured by the depth meter, which often shows it as a negative number.

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Russ Bowler with the reasons behind the recent problems with VOR keel fairing systems 10/3/06

The fairing system developed by Farr Yacht Design for the Volvo Open 70 keels has been the source of considerable interest for those following the Volvo Ocean Race. Here’s the latest press report from Farr Yacht Design on what’s gone right and wrong.

The VO70 Rule allows the designer to place the hinge axis for the canting keel up to a maximum of 150mm above the hull surface. The higher position for the axis is attractive to the designer because this provides a longer lever arm for the keel and moves the bulb further to windward. The downside is that at the surface of the hull a large opening is required to accommodate the keel fin swinging through an arc.

The challenge is to fair this opening while respecting the “no hollows” requirements of the VO70 Rule, and in particular Rule 2.2.1 which requires that no point in any transverse section be lower than any point nearer the centerline.

The team at Farr Yacht Design developed a system to fair over the required opening in the hull with a sliding plate. The plate moves with the keel by way of a barrel that slides vertically on the fin as it cants. The plate, which extends fore and aft of the fin, is retained with two “wedges” that fit full length of the sliding plate into a recess in the hull. This system offered a fair geometry for the water flow around the keel fin in the search of the least drag at all angles of cant.

A Fair Arrangement

Recognising that this system has several moving parts, that it would be subjected to wave slamming and pressure peaks from the water flow around the keel, and is difficult to access, we sized all components conservatively. All four of our Volvo Open 70 programmes were provided with the same drawing details. Each builder went about building the fairing system, in some cases making modifications to suit their construction techniques.

Movistar was our first Volvo Open 70 to be launched and completed over 22,000 miles of hard sailing (including a new 24 hour mono hull record in the Southern Ocean). Ericsson and Brasil 1 were next and also completed several thousand miles of sailing without any major issues. The first mishap was on Pirates on the first night of the race. The starboard wedge was torn out of the boat leaving the leading edge of the sliding plate exposed to the 30 knot water flow. From the remaining wedge there were indications that they may not have been built or installed to plan. We recommended a more robust wedge be built; the fastening and bonding upgraded and added a protective covering laminate on the leading edge. Since this work was completed, the system on Pirates has performed well.

From inspecting the boat in Melbourne, I can report it appeared in good working order. The same information to upgrade the wedges and installation was issued to all our boats in the race.

Second mishap was on Movistar which lost a piece of the starboard wedge on their way to winning Leg 3. Quick repairs were undertaken in the available 48 hours in Wellington. These repairs held up for 3,000 miles but the rigors of the Southern Ocean proved too much and the wedges again came away at high speed causing the sliding plates to direct a powerful stream of water into the wet box. The Movistar team is presently building new wedges to install to the same details used on Pirates, with an additional stainless steel cover strip on the leading edge for added security. Our other teams will be offered the same modification but they probably won’t action any changes given that they have no problems with their installations.

Alongside these events the same keel fairing systems on Brasil 1 and Ericsson have sailed through the worst conditions the race has to offer without incident. So what can we learn from these unfortunate events:

1. We are reminded of the principle that when designing something that has not been done before, it is important not only to consider the absolutely worst possible event but also the consequences of failures from that event. In this case if the front end of the plate lost its retaining devices through unexpected events such as material defect, improper installation, damage from impact or the like, what would be the consequences? Risk management is a part of the design process. Efforts should be made to provide a fail-safe method of retaining the plates, or a back up retention device that would keep the plates from forming scoops for the oncoming water flow.

2. While the speed and slamming events were expected, our design team, builders, shore crews and sailors have a new respect for the violent slamming and pressure peaks that occur around the keel area in these ultra high performance ocean sailing boats traveling in rough water at speeds up to 40 knots.

3. The best efforts of design and build in project can be completely ruined by the smallest detail. There are many cases of this in the engineering world. Slamming pressures and design loads are applied to the design of all details, but the actual loadings to small areas around the foils when a boat travelling at 35 knots plus lands on a wave at the wrong angle can peak to what could be higher pressures than predicted by traditional methods. While the exercise of designing and building these fairing systems was time consuming, and dealing with the problems they presented utterly frustrating, similar fairing systems may play a role in the development of high performance canting keel ocean racing yachts in the years to come. It is humiliating that this system has been the cause of such upsetting consequences to two great competitors in this race. In the future we will certainly be reviewing their necessity and approaching their design with all the wisdom this experience has given us.

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canting keels...

Discussion in ' Sailboats ' started by seamonkey , Sep 29, 2004 .

seamonkey Junior Member

as a dinghy racer,,I've never particularly liked healing...and don't feel it's really very efficient,,,I guess others would agree,since canting keels now seem to be entering the high-perf sailboat scene with gusto! How do these work.....any links to view make-up,,,pictures,,,,designs.??....thanks!  

SailDesign Old Phart! Stay upwind..

SeaMonkey, I have to ask, are you really a Brine Shrimp? (If in doubt as to whether that was an insult - No, it wasn't) CAnting keels are not really there to "stop" heeling, but to provide more Righting Moment. All that means is that you can carry more sail for the same angle of heel. As far as efficiency goes, many boats (especailly the fat/flat Open class boats, actually sail faster with more heel, since their waterlines get narrower as they heel. Pictures, etc? Well, I don't have a thousand words, but I'll try. Imagine a keel fin that comes inside the boat, with a large pin/hinge aligned with the bottom. At the top of this fin (let's say 3 feet above the hinge), there will be a hydraulic cylinder or a block and tackle, depending on the size and weight of the keel, which will be able to swing the keel from side to side. Simple, non? Steve  

........just add water ,,,it comes alive!!! yeh,,,I understand the 'keelboat dynamic' ,but rather not heel! Yes I imagined the general layout you describe,,,but there must also be some form of gasket,or sealing to prevent the ocean from finding it's way into the boat!?  

yachtie2k4 Anarchist

they use compressed air to stop the water coming into the boat  

.......but seriously,,,,,folks...........!  

The mechanism goes in a big triangular box with a lid. Takes space, but if the top is above waterline, you can pop the lid for repairs underway, and still stay dry Steve  

hummm--nasty space-taker,,,and a fair volume of H2o in that 'V' ,I'd imagine.--any detail shots or drawings to be found of the box/hinge mechanism/etc?--then I can ask less silly questions!!  

they use compressedair on skandia to keep the water out. its not ********, i know this cause the boats from my yacht club  

Doug Lord Guest

canting keels Check out post #9 under this thead: http://www.boatdesign.net/forums/showthread.php?t=4811 There are all kinds of ways to seal a canting keel .Among the most effective uses a sort of module into which the keel is inserted. A portion of the module extends forward or aft thru watertite seals to allow a lever to be attached to rotate the keel manually, hydraulically or electrically. Simon Rogers has an excellent patented design that allows the canting keel to retract as well as move fore and aft; this is a real plus on the Mini's this system was first used on. Some systems have a slight disadvantage from a wetted surface perspective in that they have a "bump" on the bottom to allow room for the keel to pivot; other designs have eliminated this bump. But as I mentioned in the post referenced above the MOST important consideration in using a canting keel is the type of extra lateral resistance you will use as the keel cants.. My favorites: CBTF for performance. kFOIL for room in the boat in cruising applications or on boats where upwind work is not at a premium.  

yachtie2k4 said: they use compressedair on skandia to keep the water out. its not ********, i know this cause the boats from my yacht club Click to expand...

mm, not really, as skandia is going over to asia & i'm hopefully movin up to new south wales & will probably be up in new south wales before skandia gets back to the club, so, no there is no chance, but i assure you that is how they do it.  

well-it would sure be great to see any pics/drawing links available!!.......thanks  

i can give you their website, but its being "repaired" which has been goin on for ages, www.wildthingyachting.com.au  

dougfrolich Senior Member

This is a setup I used for my Pac30 design  

Attached Files:

Waterproof cantbearing.jpg.

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Canting keel "module" Simply fantastic-great design!  

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