Patent attributes
A ship maneuvering device rotates a propeller at a lower rotational frequency than the rotational frequency of the minimum idling speed of an engine. A control device has a crawling speed navigation mode. A crawling speed navigation mode button that selects whether or not to execute the crawling speed navigation mode is connected to the control device. When the crawling speed navigation mode is selected, and the amount of operation of a joystick lever is at or beneath a baseline amount of operation Ms, the control device causes the rotational frequency N of the engine to be the rotational frequency Nlow of the minimum idling speed, and in accordance with the amount of operation of the joystick lever, varies the duty ratio D, which is the fraction of time T1 that a main clutch is engaged in a predetermined cycle T, within a range of no greater than 100%.
