Recent systematic model experiments demonstrate that pure loss of stability, broaching, and bow-diving are major causes of ship capsizing in following and quartering seas. Once these dangerous phenomena happen, even a ship complying with the current Intact Stability Code (IS Code) of the IMO could capsize. In this research, we propose a wing-type appendage attached to the ship bow above the water line as a new capsizing prevention device. If a ship heels, the wing-type appendage is submerged into water. Then a ship obtains additional restoring moment induced by lift force acting on a submerged wing. Since broaching and bow-diving are associated with surf-riding where a ship is accelerated by a wave up to wave celerity, ship forward velocity is enough high to obtain sufficient lift force. The submerged wing also induces additional resistance due to drag force, which helps a ship to escape from surf-riding condition and violent yaw motion. We conducted free running model experiment to examine the effectiveness of the proposed wing-type appendage to prevent ship capsizing in severe astern waves. As a result, no capsizing was observed with the wing-type appendage while capsizing due to broaching and bow-diving was observed without the wings under the same wave condition and control parameters.