The works offers the method of measuring technique, specifically, for measuring shaft transferred power by means of multiplication of shaft torsion moment and rotational speed both gauged during operation. In this topic is developed device which can measure power on the shaft of the engine. The ship propeller shaft line consists from different parts which are joined by the connecting clutch. The shaft parts are different section. The connection of shaft are done by different joints. In this topic the research cover the joints with strong gear connection and flexible connection. In the ship power plant under research the main engine is connected with propeller shaft directly without gear. In such a case the rotation speed of engine is equal to rotation of the ship propeller. During the engine running it is necessary to control the power of engine on regular basis. One of the methods of controlling main engine power is method of measuring propeller shaft turning deviation. The purpose is to increase measurement accuracy. Shaft deformation data is provided by immovable adapters and installed in non-rotary housing . At least two adapters and, being installed in housing 1, are in non-mechanical union, e.g. either electronically or optical, with relevantly to them aligned and fixed marks on top of a shaft in way of longitudinal axis. Generated impulse signal and is transmitted to recording device by adapters and . The recording device determines both time and its deviation between whatever impulses and of either forward or back front, shaft rotation speed , tangential stresses in the shaft and shaft transferred power .