Patent ID: 8016626

Claim:
A marine propulsion system comprising: an engine; a propeller arranged to be rotated by a driving force generated by the engine; a transmission mechanism arranged to convey the driving force of the engine to the propeller at least after shifting into a low speed reduction gear ratio and into a high speed reduction gear ratio; an acceleration detecting section arranged to detect acceleration of a hull propelled by the rotation of the propeller; and a control section arranged to carry out the control for changing the reduction gear ratio of the transmission mechanism; wherein the control section is arranged to control the transmission mechanism to shift from the low speed reduction gear ratio into the high speed reduction gear ratio based on the acceleration of the hull detected by the acceleration detecting section; and the control section is arranged to control the transmission mechanism to shift into the high speed reduction gear ratio, based on a first gear shift control map representing criteria for shifting the transmission mechanism from the low speed range reduction ratio into the high speed range reduction ratio by using a decreasing ratio of the acceleration of the hull and an accelerator opening.