Sail Propulsion Laboratory

So far the boat is pretty difficult to control:

• With single sail,  changing the sail sheet angle moves center of effort too much.
• To work efficiently, the sail must be at a certain angle to the apparent wind direction, with about 3° precision. Our wind vane measures wind direction with 22.5° precision, which is definitely not enough. measurements will be further affected by rocking of the boat.
• The hull is too thin, the displacement is relatively high, so the waterline is close to the mid-height of the hull. Heeling of the boat dramatically changes the underwater shape of the hull along and the helm balance.

Using wing sail with aileron instead of traditional sail should solve the first two problems. Center of effort of the wing is exactly at the mast (25% of the chord length). Aileron will keep the wing at a constant angle of attack to the apparent wind direction.
To get around the third problem we will temporarily use a hull with more predictable characteristics, such as catamaran (high initial stability, low absolute stability).
To research properties of the wing sail we are building a prototyping platform called “Sail Propulsion Laboratory” (SPL) that will:

• Allow changing relative location and sizes of all the elements (hull, sail, aileron, rudder, keel, etc.)

• Allow measuring and recording of the different forces, moments, and angles.