A buoyant under influence of sea waves and wind excitation experiences unwanted linear and rotational motions. These motions may affect proper performance of high precision equipment placed on the buoyant. Stable platform is one of the solutions employed for decreasing amplitude of the sea induced motions. Design of an optimal fuzzy controller for a tripod stable platform installed on the deck of a medium boat is considered in this paper. For this purpose, a fuzzy controller is proposed for the stable platform control. Furthermore, a 3D virtual model of the boat and the stable platform is developed and the fuzzy controller is applied to the virtual prototype using the co-simulation technique of MATLAB and ADAMS software. The fuzzy controller is then optimized using the genetic algorithm (GA). Moreover, a linear quadratic regulator (LQR) is designed for the stable platform control. The controllers are then applied to the virtual prototype and their performance in the presence of sea wave excitations is examined. Simulation results reveal that the tripod stable platform controlled with the optimal fuzzy controller can reduce pitch and roll motions up to 90 percent and reduce heave motion up to 55 percent.