Diagrams to explain basics of sailing

[takluyver]

@smaria if you have time to do some more line drawings, I'd like to add to the control page a brief introduction to the challenge of going upwind, tacking, and maybe even velocity made good. Obviously the explanation would be much clearer with some illustrations.

[smaria]

Assuming a few months time is a suitable time span, sure, I'll get around to it.

[takluyver]

Thanks! Whenever you have time will be fine. 😃