This is a really fun game, congratulations on releasing it. If I could make one suggestion - it would be awesome if you could use the mouse wheel to change the orientation of your sails rather than having to move all the way over to the right of the screen to use the slider.
It does arrow left/right or a/d for tiller and arrow up/down or w/s for sail trim. If you can manage using wasd, then r will [un]furl sails. I haven't figured out the cannon button yet if there is one.
Edit: r for [un]furl sails [0], also <shift> apparently fires
