Patent ID: 8589004

Claim:
A boat propulsion system comprising: a plurality of boat propulsion units arranged to switch between forward and reverse propulsion directions independently from each other and to be steered independently from each other, the plurality of boat propulsion units including a first port-side propulsion unit disposed to the left of a center line extending in a longitudinal direction of a hull, a second port-side propulsion unit disposed to the left of the first port-side propulsion unit, a first starboard-side propulsion unit disposed to the right of the center line, and a second starboard-side propulsion unit disposed to the right of the first starboard-side propulsion unit; an operation device arranged to command travel at least in the directions of forward, reverse, left, and right; and a control unit programmed to individually control the forward and reverse propulsion directions, a propulsion force, and a steering angle of each of the plurality of boat propulsion units such that when the control unit receives an operational command from the operation device for travel in a lateral direction of the hull, a point of action of a first resultant force, which is a resultant force of propulsion forces generated by the first port-side propulsion unit and the first starboard-side propulsion unit, is positioned behind, in the longitudinal direction of the hull, a point of action of a second resultant force, which is a resultant force of propulsion forces generated by the second port-side propulsion unit and the second starboard-side propulsion unit.