amount of power is transmitted to the propeller. In order to operate efficiently in the typically slow speed through the water, the propeller must be large enough to generate more upwind thrust than the combined downwind force of the wind turbine and the air and water resistances of the ship structure itself.

* With the wind from the side, i.e. on a reach, the wind turbine's thrust pushes the ship sideways, which should therefor have a lateral surface such as a keel in order to reduce leeway. Thus equipped the wind turbine can be also