Design of anti-capsize ship for patrol vessel with the self-righting moment

The patrol boat is one of the critical aspects for archipelago countries, such as Indonesia, to supervise and maintain the sea border. Due to rough sea conditions, the patrol boat could lose its stability due to the loss of a self-righting roll moment in severe waves. One of the most challenging aspects is to ensure the sufficient stability of the patrol boat during rough conditions. Another challenge is to design a boat that has a self-righting moment during rolling in extreme conditions. This paper examines the design of an anti-capsize ship by improving the self-righting moment with different deck houses height. The rough condition is described when the boat experiences a roll angle of 170°. The principal dimensions of the patrol boat, i.e., Lpp, B, H, T, are 13.0 m, 4.2 m, 2.19 m, and 1.15 m, respectively. Four different deck house heights are compared to obtain the best self-righting roll moment with a height increment of 0.1 m. The physical model is implemented with ship model 1:27.4. In addition, computational fluid dynamics (CFD) is also used to support the proof of the existence of the self-righting roll moment. It is revealed that the center of gravity and buoyancy are essential parameters to acquire the self-righting moment. The height of the deckhouse improves the center of the metacenter, which influences the righting arm of ship stability. The results show that our ship design has a self-righting moment during heel at 180°.