Design of Anti-Capsize Ship for Patrol Vessel with the Self-Righting Moment

Abstract

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°.

Analysis of deck house height and center of gravity in anti-capsize patrol boat

“…The self-righting moment is a concept where the ship can return to its upright position after being upside down to a certain degree or even completely upside down (180°) without the help of an external force. The previous study of a patrol boat with an effective self-righting moment was performed using experimental and numerical methods [1,2]. The results showed that the numerical method has the same phenomenon as the experiment: the ship has self-righting in all condition load cases.…”

“…The reference ship model based on MV Barracuda which was designed in previous studies [2]. For the main dimension of the ship can be seen in Table 1 and for the three dimension model shows in Figure 1.…”

Numerical Computation of Restoring Time and Prediction of Self-Righting Process

“…Guan et al proposed a design method of self-righting decks, and they analyzed stability based on the combination of the particle swarm optimization and the sequential quadratic programming [18]. Trimulyono et al examined the design of an anti-capsize ship by improving the self-righting moment with different heights of deck house and designed a ship whose restoring arm is positive when the roll angle is between 0 • and 180 • [19]. With the improvement of algorithms and software, the efficiency of self-righting designs has greatly increased compared with traditional experiments.…”