Measuring the hull of a sailboat for a mathematical calculation of resistance

An introduction to the Admiralty Small Boat Chart (Mercator projection)

Comparing Sea-Doo's S3 & ST3 Hulls

Sailing full TIME, What size sailboat do you actually need

COMMENTS

Comparing Design Ratios

However, with the help of design ratios, you can not only compare and contrast different designs, but get a pretty good idea, sight unseen, as to how a boat is going to perform under sail. The Beneteau Sense 46 is a typical modern cruising boat, with an SA/D of 19, a Ballast Ratio of 28 percent and a D/L of 159.

Understanding Sailboat Design Ratios

Our 'Sailboat Design Ratio Calculator' takes all the hard work out of calculating the numbers andwill provide a valuable insight into a sailboat's performance and handling characteristics. We make a small charge of $4.99 for this useful tool as a contribution towards the costs of keeping this website afloat. ThisSailboat Design Ratio Calculator ...

PDF THE DESIGN RATIOS

with explanations of the various design ratios, publishing one a week. I admit to having an ulterior motive. Many years ago, a client of mine informed me of his invention of what he called the S Number (S#), which is a way to rate the performance of all sailboats on a scale of 1 to 10 using the Sail Area/Displacement ratio (SA/D) and the

A Closer Look at the Rationale Behind the Ratios

A Closer Look at the Rationale Behind the Ratios. Sailboat performance varies based on the eye of the beholder. Racers want light-air alacrity and a willingness to plane while cruisers want directional stability and reasonable speed with moderate sail area. A boats design dimensions and a few simple ratios give some hints about these attributes.

Hands-On Sailor: How Sailboats Measure Up

In the formula, displacement in pounds is divided by 64 (the density of seawater) to obtain cubic feet, which are in turn converted to square feet to make the ratio unit-free. On a spreadsheet, the formula would be S/ (D/64) (2/3). Nominally, the higher the SA/D, the more lively the boat's sailing performance.

MODERN SAILBOAT DESIGN: Quantifying Stability

Its stability ratio is thus 6.2: 196.56 ÷ 31.68 = 6.2. As a general rule, a stability ratio of at least 3 is considered adequate for coastal cruising boats; 4 or greater is considered adequate for a bluewater boat. The boat in our example has a very healthy ratio, though some boats exhibit ratios as high as 10 or greater.

Sailboat Calculator

A tool to calculate performance ratios for monohull sailboats. Use the search bar to look up dimensions for boats currently in our database. You may also enter a boat's dimensions directly in Part 2.

Compare

A Ballast/Displacement ratio of 40 or more translates into a stiffer, more powerful boat that will be better able to stand up to the wind. Bal./Disp = ballast (lbs)/ displacement (lbs)*100 Disp./Len.: The lower a boat's Displacement/Length (LWL) ratio, the less power it takes to drive the boat to its nominal hull speed. less than 100 ...

Sail Calculator

Sail Area / Displacement ratio - The SA/D ratio is like the power/weight ratio of an automobile. A high SA/D ratio (> about 18) indicates a powerful rig, while a low ratio indicates a more docile boat. Length / Beam ratio - A long, narrow hull with limited interior space is easier to drive than a short, fat one with plentiful capacity ...

Measuring Performance

Most sailboats fall between 100 and 400 on this rating scale. At the low end reside light weight speedsters and at the high end are heavy vessels that need a lot more sail area to attain the performance of vessels toward the lower end of the scale. The D/L ratio is a handy way to empirically make boat-to-boat comparisons.

Basics of Sailboat Hull Design

The first is the displacement to length ratio. The formula to calculate it is D / (0.01L)^3, where D is displacement in tons and L is waterline length in feet. But most sailboat specifications, like those found on sailboatdata.com, list the D/L Ratio. This ratio helps understand how heavy a boat is for its length.

Program Guides: Yacht Design: Ratios

Ratios. Below are explanations of the various terms and coefficients used for comparison of boat designs. Designers use them when comparing designs from their own drawing boards and those of other designers. The same info can be used by the layman to assist in selecting a design to build. (from the site)

Comfort, Capsizing, and SailCalc

Westsail 28. 41.08. Pounds/Inch. Irwin 28. 707. Westsail 28. 804. As you can see, the capsize ratio of both boats is below the 2.0 seaworthy standard set by the CCA (and interestingly lower than the above two much larger sailboats). However, the "motion comfort" (Brewer's comfort ratio) shows a much larger disparity.

Sailboat Ratios to Consider When Buying One

A ballast ratio more than 40 will be more powerful and more resistant to wind. A good ballast ratio however will mean that the boat might not be as comfortable for leisure. A very high ballast ratio is probably a better parameter for sport fans. These are the three main sailboat ratios to consider when buying a boat.

Sailboat Guide

A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more. Formula. : Sail area in square feet, derived by adding ...

Sailboat Design Ratios

The displacement length ratio is a measure of a boat's speed potential. For displacement boats (most sailboats), speed potential is a function of waterline length (unless your planing or surfing down a wave). Longer waterline boats can go faster. Lighter boats accelerate faster and reach hull speed with less wind.

Sailboat Calculator

The Sailboats Calculators below will enable you to calculate the main Sailboat Ratios, using data that you can retrieve from the Boat table or your own data. We will be adding more Calculators along the way and more in-depth explanations of how they work and what they can help you with. Hopefully you will enjoy them and find them useful to search or understand the characteristics of your or ...

Comparing capsize and comfort rates of boats

For example: Capsize Ratio = Beam / (Displacement / 64)**0.333 Notice the only factors involved are Beam and Displacement. This means that, for the same displacement, a boat with a light-weight construction and a deep fin keel will have the same number as boat with heavy construction and a shoal-draft keel.

Sailboat comparator

Last models integrated as of Sept. 5, 2024. SailboatLab allows you to find the sailboats that best fit a given navigation program by computing fitness scores from boats characteristics and ratios.

What is a Sailboat Capsize Ratio and how to measure it

A sailboat capsizes ratio is a parameter used to show whether a boat can recover from an inverted, capsized position or not. This term was mainly developed after the Fastnet race disaster. This was a 1979 race where a storm destroyed several yachts during the last day of the race, also causing 19 victims.

Sailboat Ratios

Sailboat Ratios There are many ratios that can be used to compare boat design dimensions, many of which are mainly of interest to professional boat designers. Here's a few ratios of use to the average boatowner (or wannabe) in comparing boats. General Sailing Categories (in order of descending performance): Racer Racer/Cruiser Cruiser/Racer Cruiser Displacement/Waterline Length - D/L ...

What are the meanings of the capsize ratio and the comfort ratio

Participant. Motion Comfort Ratio was developed by Boat Designer Ted Brewer. The formula predicts the speed of the upward and downward motion of the boat as it encounters waves and swells. The faster the motion the more uncomfortable the passengers. Thus, the formula predicts the overall comfort of a boat when it is underway.

SailboatData.com

SailboatData.com …is a database that contains information on over 9000 production and semi-production sailboats dating back to the late 1800's. COMPARE BOATS To compare up to three boats at one time, click the (+) Remove a compared boat by clicking (-)

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However, with the help of design ratios, you can not only compare and contrast different designs, but get a pretty good idea, sight unseen, as to how a boat is going to perform under sail. The Beneteau Sense 46 is a typical modern cruising boat, with an SA/D of 19, a Ballast Ratio of 28 percent and a D/L of 159.

Our 'Sailboat Design Ratio Calculator' takes all the hard work out of calculating the numbers andwill provide a valuable insight into a sailboat's performance and handling characteristics. We make a small charge of $4.99 for this useful tool as a contribution towards the costs of keeping this website afloat. ThisSailboat Design Ratio Calculator ...

with explanations of the various design ratios, publishing one a week. I admit to having an ulterior motive. Many years ago, a client of mine informed me of his invention of what he called the S Number (S#), which is a way to rate the performance of all sailboats on a scale of 1 to 10 using the Sail Area/Displacement ratio (SA/D) and the

A Closer Look at the Rationale Behind the Ratios. Sailboat performance varies based on the eye of the beholder. Racers want light-air alacrity and a willingness to plane while cruisers want directional stability and reasonable speed with moderate sail area. A boats design dimensions and a few simple ratios give some hints about these attributes.

In the formula, displacement in pounds is divided by 64 (the density of seawater) to obtain cubic feet, which are in turn converted to square feet to make the ratio unit-free. On a spreadsheet, the formula would be S/ (D/64) (2/3). Nominally, the higher the SA/D, the more lively the boat's sailing performance.

Its stability ratio is thus 6.2: 196.56 ÷ 31.68 = 6.2. As a general rule, a stability ratio of at least 3 is considered adequate for coastal cruising boats; 4 or greater is considered adequate for a bluewater boat. The boat in our example has a very healthy ratio, though some boats exhibit ratios as high as 10 or greater.

A tool to calculate performance ratios for monohull sailboats. Use the search bar to look up dimensions for boats currently in our database. You may also enter a boat's dimensions directly in Part 2.

A Ballast/Displacement ratio of 40 or more translates into a stiffer, more powerful boat that will be better able to stand up to the wind. Bal./Disp = ballast (lbs)/ displacement (lbs)*100 Disp./Len.: The lower a boat's Displacement/Length (LWL) ratio, the less power it takes to drive the boat to its nominal hull speed. less than 100 ...

Sail Area / Displacement ratio - The SA/D ratio is like the power/weight ratio of an automobile. A high SA/D ratio (> about 18) indicates a powerful rig, while a low ratio indicates a more docile boat. Length / Beam ratio - A long, narrow hull with limited interior space is easier to drive than a short, fat one with plentiful capacity ...

Most sailboats fall between 100 and 400 on this rating scale. At the low end reside light weight speedsters and at the high end are heavy vessels that need a lot more sail area to attain the performance of vessels toward the lower end of the scale. The D/L ratio is a handy way to empirically make boat-to-boat comparisons.

The first is the displacement to length ratio. The formula to calculate it is D / (0.01L)^3, where D is displacement in tons and L is waterline length in feet. But most sailboat specifications, like those found on sailboatdata.com, list the D/L Ratio. This ratio helps understand how heavy a boat is for its length.

Ratios. Below are explanations of the various terms and coefficients used for comparison of boat designs. Designers use them when comparing designs from their own drawing boards and those of other designers. The same info can be used by the layman to assist in selecting a design to build. (from the site)

Westsail 28. 41.08. Pounds/Inch. Irwin 28. 707. Westsail 28. 804. As you can see, the capsize ratio of both boats is below the 2.0 seaworthy standard set by the CCA (and interestingly lower than the above two much larger sailboats). However, the "motion comfort" (Brewer's comfort ratio) shows a much larger disparity.

A ballast ratio more than 40 will be more powerful and more resistant to wind. A good ballast ratio however will mean that the boat might not be as comfortable for leisure. A very high ballast ratio is probably a better parameter for sport fans. These are the three main sailboat ratios to consider when buying a boat.

A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more. Formula. : Sail area in square feet, derived by adding ...

The displacement length ratio is a measure of a boat's speed potential. For displacement boats (most sailboats), speed potential is a function of waterline length (unless your planing or surfing down a wave). Longer waterline boats can go faster. Lighter boats accelerate faster and reach hull speed with less wind.

The Sailboats Calculators below will enable you to calculate the main Sailboat Ratios, using data that you can retrieve from the Boat table or your own data. We will be adding more Calculators along the way and more in-depth explanations of how they work and what they can help you with. Hopefully you will enjoy them and find them useful to search or understand the characteristics of your or ...

For example: Capsize Ratio = Beam / (Displacement / 64)**0.333 Notice the only factors involved are Beam and Displacement. This means that, for the same displacement, a boat with a light-weight construction and a deep fin keel will have the same number as boat with heavy construction and a shoal-draft keel.

Last models integrated as of Sept. 5, 2024. SailboatLab allows you to find the sailboats that best fit a given navigation program by computing fitness scores from boats characteristics and ratios.

A sailboat capsizes ratio is a parameter used to show whether a boat can recover from an inverted, capsized position or not. This term was mainly developed after the Fastnet race disaster. This was a 1979 race where a storm destroyed several yachts during the last day of the race, also causing 19 victims.

Sailboat Ratios There are many ratios that can be used to compare boat design dimensions, many of which are mainly of interest to professional boat designers. Here's a few ratios of use to the average boatowner (or wannabe) in comparing boats. General Sailing Categories (in order of descending performance): Racer Racer/Cruiser Cruiser/Racer Cruiser Displacement/Waterline Length - D/L ...

Participant. Motion Comfort Ratio was developed by Boat Designer Ted Brewer. The formula predicts the speed of the upward and downward motion of the boat as it encounters waves and swells. The faster the motion the more uncomfortable the passengers. Thus, the formula predicts the overall comfort of a boat when it is underway.

SailboatData.com …is a database that contains information on over 9000 production and semi-production sailboats dating back to the late 1800's. COMPARE BOATS To compare up to three boats at one time, click the (+) Remove a compared boat by clicking (-)