Abstract: A marine reduction gearbox, or transmission, is provided with variably engageable clutches connected in torque transmitting relation between a prime mover and a propeller shaft. These variably engageable clutches permit the prime mover to be connected to the propeller shaft in partial torque transmitting association. One advantage of this type of apparatus is that the prime mover can be partially loaded during crash reversal procedures while the propeller shaft is still and inhibited from rotating by the action of a brake. This preloading of the prime mover while at idle speed increases the power output of the prime mover and prepares it for an eventual connection to a rotatable propeller shaft with the brake disengaged or partially disengaged. This procedure prevents the stalling of the prime mover, especially when the prime mover is a high break mean effective pressure engine.