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The Physics of Sailing (2003)
The physics of sailing
Well it does a little, but when it does, the keel, a large nearly flat area under the boat, has to push a lot of water sideways. These two horizontal components have equal size but opposite direction: as forces they cancel, but they make a torque tending to rotate the boat clockwise. As the boat heels to starboard, the lead on the bottom of the keel, which has a substantial fraction of the weight, moves to port and exerts an anticlockwise torque.
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