-
Sail Area / Displacement
18.49
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.-
[-16] : under powered
-
[16-20] : good performance
-
[20-] : high performance
SA/Disp. = SA ÷ (Disp. ÷ 64)2/3
-
-
Speed Number
nan
The "S Number" or "S# (Speed Number)" is a performance metric used to evaluate sailing vessels, specifically comparing the potential speed of a yacht or sailboat relative to its displacement. It essentially provides a dimensionless value indicating the speed potential of the boat based on its sail area and displacement.-
[-2] : underpowered
-
[2-3] : cruiser
-
[3-5] : racer cruiser
-
[5-] : fast
-
-
Ballast / Displacement
34.00
A measure of the stiffness and power of a boat. Predictes the ability of a boat to stand up to the wind.-
[-40] : less stiff; less powerful
-
[40-] : stiffer; more powerful
Bal./Disp. = Bal. / Disp. * 100
-
-
Displacement / Waterline Length
180.63
A measure of the ability of a boat to reach nominal hull speed.-
[-100] : ultralight
-
[100-200] : light
-
[200-300] : moderate
-
[300-400] : heavy
-
[400-] : very heavy
Disp./LWL = (Disp. / 2240) / (0.01 * LWL)3
-
-
Comfort Ratio
18.42
A measure of motion comfort - it allows the comparison of boats of similar size and type. Generally, the faster the motion, the more jarring/uncomfortable the ride.-
[-20] : lightweight racing boat
-
[20-30] : coastal cruiser
-
[30-40] : moderate bluewater cruiser
-
[40-50] : heavy bluewater cruiser
-
[50-] : very heavy bluewater cruiser
CR = Disp. / (0.65 * (0.7 * LWL + 0.3 LOA) * (Beam1.33))
-
-
Capsize Screening Ratio
2.24
A measure of the bluewater capabilities of a boat.-
[-2] : better suited for ocean passages
-
[2-] : better suited for coastal passages
CSF = Beam/(Disp.1/3)
-
-
Hull Speed
7.36
Hull speed, also known as displacement speed, is a rule of thumb to estimate the maximum speed a displacement hull can efficiently travel through water. It is primarily based on the length of the boat's waterline (the length of the hull at the water's surface). This concept originates from the observation that the speed of the wave created by the boat starts to limit the boat's speed once the wave's length is equal to the waterline length of the boat.-
[-5] : slow
-
[5-] : fast
Hull Speed = 1.34 * (Waterline Length)0.5
-