Patrol vessel is an essential part of offshore security archipelago countries such as Indonesia. The main feature of patrol vessel is operating in rough waves during operation. Ship stability is one of the challenging aspects of patrol vessel because, in extreme conditions, the ship can capsize due to losing a self-righting moment. The present paper carried out a study of a patrol vessel with a self-righting moment in extreme conditions. The condition is a ship with rolling up to above 180°. Thus, the ship can capsize because of losses of the self-righting moment in rough condition. An experimental study is carried out to model a ship with a rolling angle above 180°. The principal dimension of ships Lpp, B, H, T, are 13.0 m, 4.2 m, 2.19 m and 1.15 m, respectively. The study was carried out with a physical model of ship 1:27.4. The model is made using 3D printing to maintain the hull integrity. In the present paper, only the full load condition was tested in the experiment condition. It was showed the ship design was proven to have a self-righting moment in the rolling angle above 180°.