No person on any Indian ship shall, when the ship is going ahead, give a helm or steering order containing the word “starboard” or “right” or any equivalent of “starboard” or “right” unless he intends that the head of the ship shall move to the “right” or give a helm or steering order containing the word “port” or “left” or any equivalent of “port” or “left” unless he intends that the head of the ship shall move to the left.