Talk:Windmill ship

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How does this not violate thermodynamics -- that for every action there is an *equal* and opposite reaction. How can you do better than standing still? — Preceding unsigned comment added by 136.159.108.125 (talk) 02:01, 14 November 2012 (UTC)

- It works because of the difference between speed through the air and speed through the water. Power is force x speed, and since (when heading directly into wind) the air speed is less than the water speed, a greater propulsive force can be generated in the water than the drag force on the windmill, for an equal power. It of course only works when there is wind to drive the boat- in calm weather, there is no speed differential and so no net forward thrust. Another way to look at it is that each blade of the wind turbine is tacking into wind. — Preceding unsigned comment added by 2.124.245.53 (talk) 15:49, 8 December 2015 (UTC)