Method of hydraulically controlling a marine speed reducing and reversing machine in crash astern operation

A hydraulic clutch control method of a marine reduction and reverse gear in a crash-go-astern operation, for switching operating means of a hydraulic clutch mechanism provided to the marine reduction and reverse gear from a forward setting to a reverse setting in a stroke so as to abruptly stop a ship traveling forward, said method comprising the steps of:

• (i) when switching the operation means from the forward setting to the reverse setting, changing a clutch pressure from a forward driving clutch pressure to a reverse driving clutch pressure via a neutral pressure;
• (ii) if it is judged that there is a fear of stalling due to a shock of the clutch switching in the operation, dropping and maintaining the reverse driving clutch pressure at a predetermined standby clutch pressure set between the neutral pressure and a maximum pressure of the reverse driving clutch pressure and suitable for avoiding stalling;
• (iii) if it is judged that there is no fear of said stalling, increasing the reverse driving clutch pressure;
• and
• (iv) repeating steps (ii) and (iii) until the crash-go-astern operation becomes stable.