A theoretical study on psychological energy of a captain operating in conflict sea is made from the view point of thermodynamics. A relationship which corresponds to the PVT system of thermodynamics is found among P the blockage pressure, V the wide of the territory of a ship and T the temperature of menace in sense of her captain. Feeling of efficacy of a captain is defined effectively by the thermodynamic work. A model of psycho-engine in a captain is proposed keeping the conservation low of psychological energy. The psycho-engine change his willpower in motivation pool to his feeling of efficacy which is pooled in satisfactory experience. The psycho-entropy low which represents that the quality of motivation degenerates is applied to obtain a equilibrium velocity in operation in a straight narrow canal. The obtained velocity is proportional to square root of the width of the canal.