Mary,

Any object with more then 100 liter volume enclosed in itself will carry an adult. That is not the point. The point is that it also needs to go somewhere under sailpower. And safety requirements alone demand that it does so relatively efficiently. Otherwise the boat won't be able to sail clear of the being trapped at a (rocky with big surf) leeward shore when the wind pipes up.

The slower the boat is made the more difficult it is to make the boat point and the more easily you can get into trouble. Do the math and modelling and find out for yourself.

Maybe we should design a peddle system to go with that F10 or F11 so kids can paddle to safety ?

Wouter