US Patent 7909670 Marine propulsion system

A marine propulsion system includes an engine, propellers rotated by the engine, a transmission mechanism arranged to transmit a driving force of the engine to the propellers with a speed thereof shifted to at least a low speed reduction ratio or a high speed reduction ratio in forward travel and reverse travel, and a gear shift switch operable by a user to shift speed reduction ratios of the transmission mechanism to the low speed reduction ratio in at least the reverse travel. This arrangement provides a marine propulsion system in which both of acceleration performance and a maximum speed can approach levels that a user desires.