METHOD FOR OPTIMIZING THE EFFICIENCY IN SHIPS WITH BOW AND STERN SCREWS AS WELL AS AN ARRANGEMENT FOR ADJUSTING THE ROTATION SPEED OF THE BOW SCREW

摘要

Special ferries may have identical propulsion systems at bow and stern in order to avoid turning the ship on a change in the direction of travel. During sailing the rotation speed of the forward screw is lower than that of the aft screw. According to the invention, the sum of the true outputs of both propulsion systems is set to a minimum to optimise efficiency. In the relevant arrangement, there is a regulator (10) using the outputs of both drives as input values and the rotation speed of the bow screw at which the sum of the outputs is at a minimum is determined in the regulator (10).