You might want to ask some friends or relatives who do not know about sailing to sit down and try to play the game for a while and watch how they play, and ask for things they might find easier. Especially if you're going to sell it, I know a lot of companies spend a lot of money and several months doing this, but even getting some friends or kids or buy some people some beer to do it, I bet it would be helpful!

Looks great, you're probably the envy of many people here, having finished a professional quality 3D game.
Bye!
JPM