This is a good start, but the physics of sailing is much more complex than presented in your app. For instance, a sailboat is not powered by the wind pushing on the sail.
It works like this. The wind is split by the leading edge of the sail (the mast, headstay, or luff). It is split into two turbulent streams, one on each side of the sail. One stream has slightly less force on the sail so the sail begins to move in that direction. As the flow stabilizes over that side, the wind moves faster on that side than on the turbulent side. This creates lift like an airplane wing. So the wind is actually pulling the sail, not pushing it.
Lift on the sail causes the boat to heel (lean over). Some of the lifting force is counterbalanced by the keel underwater keeping the boat upright. The remainder of the force pushes the boat downwind. However, the flat keel underwater prevents the boat from sliding downwind, with the result that the boat is forced forward.
I recommend you read this book for your next version:
It works like this. The wind is split by the leading edge of the sail (the mast, headstay, or luff). It is split into two turbulent streams, one on each side of the sail. One stream has slightly less force on the sail so the sail begins to move in that direction. As the flow stabilizes over that side, the wind moves faster on that side than on the turbulent side. This creates lift like an airplane wing. So the wind is actually pulling the sail, not pushing it.
Lift on the sail causes the boat to heel (lean over). Some of the lifting force is counterbalanced by the keel underwater keeping the boat upright. The remainder of the force pushes the boat downwind. However, the flat keel underwater prevents the boat from sliding downwind, with the result that the boat is forced forward.
I recommend you read this book for your next version:
http://www.amazon.com/Sail-Power-Complete-Guide-Handling/dp/...