K/proa

Model No.1 was the first attempt to design a sailing solution. It didn't exhibit force balancing of the sail and keel lift forces - they weren't satisfactorily aligned. Nor did it steer itself with respect to the apparent wind. I found that the central location of the sail on the outrigger hull placed the rearward projection of the sail's total-lift vector aft of the aft keel/rudder. The model simply turned into the wind and no amount of keel/rudder adjustment would make it bear off the wind.

The 2nd iteration of Model No.1 used a hinged parallelogram to move the sail forward. This change placed the total-lift vector between the keel/rudders. It produced a self-steering boat that held its course with respect to the apparent wind and followed wind shifts smoothly. This and all subsequent models were completely self-steering. Once adjusted, the model maintained a constant heading with respect to the apparent wind.

The need to also place the total-lift vector through the center of lateral resistance was addressed by extending the base of the sail outward. This aligned the lift vector of the sail with the lift vectors of the keel/rudders and produced a force-balanced craft, i.e. no overturning moments were generated.

	The 3rd iteration of Model No.1 was used to test various positions of the sail. The final position (shown) was satisfactory both for self-steering and force balancing. The model sailed quickly and remained level upon the water.