Abstract Based on the oscillating movement of S-start of strikes and startles in northern pike, the motion equations for S-start were established for the developed fish-like robot. Through the calculations of the fluid thrust, the boundary layer friction and the added mass in lengthwise direction, the propulsion efficiency of S-start was analyzed. By using the multi-step simulation experiments of strikes and startles of S-start, the underwater maneuverability performance indices such as kinetic energy, input power and propulsion efficiency were obtained, which provides theoretic reference for the experimental research and optimal design of the underwater maneuvering propulsion of fish-like robots．
