i have a twin screw/twin rudder boat. at some speeds when i steer to port, the boat will begin to turn to port, then stop turning and sometimes will begin to turn to starboard while the rudder angle remains in a position to indicate a port turn. what is happening?
At the moment when the boat stops turning to port, the rudders ventilate on the low pressure side of the rudders. Often this creates rudder force reversal either resulting in little or steering force or more likely developing starboard turning forces. Often this situation can be corrected by properly adjusting the toe-in/toe-out angles of the rudders by changing the length of the tie bar connecting the tiller arms of the rudders. If adjusting the length of the tie bar does not correct the problem, then eliminating the air/ventilation path to the rudders is necessary.
