just had this mad idea, basically replace all the sails on a clipper with turbines. Such that the drag will push the ship forwards in the same manner as like sails, but the turbines will be rotating, thus generating power which can go direct to the ships propellers.
Would that system yield more power than sails alone?
Note we could make the turbines from carbon fibre etc, so they would be let us say, the same weight as the conventional sails – just so its easy to work out.
Be a nice fuelless solution.