Abstract—At present, hydraulic actuators have been strongly highlighted in the shipbuilding industrial applications. The actuators are classified into three types according to their operation, such as scotch yoke, rack and pinion, rod and crank type. However, hydraulic actuators are more difficult than others electric motors because of nonlinear flow-pressure characteristics and many cases of torque between moving parts. In this paper, in order to obtain the data of the valve locking torque value of the scotch yoke, the pressure was applied at a pressure of 6~16 MPa and analysis by depending on cylinder diameter and yoke length using ANSYS tool. According to the results of generating torque value, it is understood that the torque increases as the cylinder diameter increases and the moment arm becomes longer. It can be also seen that the all average error rates of experimental values and program analysis values are only under the 3%.