Use of simulations to predict lifeboat survivability in extreme waves and the effectiveness of coxswain performed actions

Simulations were used to investigate the performance of lifeboats in high sea states using a virtual wave tank. Numerical simulations were performed in regular and irregular waves to study launch performance in extreme weather conditions. Limitations in launch equipment and the role of the timing of coxswains’ actions were investigated. The study indicated that the lifeboat may not be able to successfully launch when significant wave heights are above 8 m and the lifeboat is launched near the trough of a wave. High initial setback and continuous wave forces result in the vessel being unable to clear away from the launch platform. As wave heights increase, the amount of setback and time to exit the launch area increases. Over 35% of launches resulted in the lifeboat being unable to clear from the launch area when significant wave heights were 10 m or above. The study also identified that delay in completion of actions performed by the coxswain, such as releasing the lifeboat hooks and applying throttle, can increase setback and time to exit the launch area.