What is the maximum speed of a sailboat?

Answer 1

Maximum Speed of a Single-Hull

Displacement Boat

Hull Speed = 1.34 x the square root of the LWL

LWL: length of the hull at the waterline.

Please note: this is the theoretical maximum speed of a displacement monohull and does not take into account the following criteria:

1. Hull Design - each hull's contours will effect the laminar flow, that is how smoothly and effortlessly the water flows over it. Every design has a certain co-efficient of drag, and depending on the hull, more or less inherent and induced drag.

2. Displacement - just like with a car, the lighter you make a boat, the faster you can make it go.

3. Sail Area/Displacement Ratio - this is a bit like the power/weight ratio in a car. Since the sails are pushing the boat through the water, the heavier the boat, the larger the sails will have to be in order to take maximum advantage of the hull speed formula. If two vessels have the same hull design and the same sail area, the one with the lower displacement will be the faster vessel.

4. Type of Keel - there are two main types of keels, full and fin. Full means that the keel runs the length of the underside of the hull and fin is just what it sounds like - a fin placed roughly amidships. Depending on the weight and shape of the keel the boat will move faster or slower.

If you want to know the hull speed of a particular make and model of boat, see if you can find a polar diagram. Polar diagrams, or plots show the speed of the hull at various points of sail and with various wind velocities.