Patent ID: 7762858
Filing Date: 2010-07-27
Classification: B63H

Abstract:
1. A propulsion system for a boat, the propulsion system comprising: an engine; a propeller arranged to be rotated by the engine; a transmission mechanism arranged to operate in at least a low speed reduction ratio and a high speed reduction ratio, and arranged to transmit a driving force generated by the engine to the propeller with a speed thereof shifted to one of the low speed reduction ratio and the high speed reduction ratio; a control unit arranged to output a signal to control a gear shift in the transmission mechanism on the basis of a load of the engine and a speed of the engine; and a cavitation detecting section arranged to detect cavitation generated in conjunction with rotation of the propeller; wherein the control unit is arranged to control the output of the signal to the transmission mechanism to change the gear reduction ratio to the high speed reduction ratio when cavitation is detected by the cavitation detecting section.