We designed, built and tested 2 hulls of the same dimension, same electronics, same weight (ballast), same sail. The major difference is that one is a solid rigid hull “Classic” and the other one is a shape shifting hull “Birthday”. We also tested a commercial sailing boat called University club (sales at 950 HKD - expensive for poor performance).
The commercial boat could not handle the relatively strong wind and went flat on the water and drifted away. Protei “Classic” Sailed well but it could not tack. Protei “Birthday” could tack and jibe - most maneuverable of the three, but was a little slower than “Classic”. The round hole in “Classic” hull is to reduce it’s side force so it provides a side force similar to Protei “Birthday”.
“Birthday” and “Classic”
Motor (Hull & Sail)