Geometric Effect of Bulbous Bows to the Hydrodynamic and the Probability of Slamming on Catamaran

Achieving optimal efficiency, good performance, and cost-effectiveness is the main challenge in ship design. Using a bulbous bow is part of attaining an excellent design to reduce drag and dynamic load caused by waves and slamming. The design of the bulbous bow is commonly determined by shape geometric based on laboratory testing or computer optimization. This article compares the probability of slamming into a catamaran NPL hull without a bulbous bow and with a bulbous bow. Variation of the geometric bulbous bow and its effect on hydrodynamics and slamming was investigated. This study uses a numerical method by CFD software and applies secondary data of model testing on the same object as another researcher. The adjustment of the bulbous bow led to a 15.22–17.07% reduction in wave drag. According to the bulbous bow variant, increasing the linear parameter of the length of the bulbous bow reduces the wave drag and the probability of slamming to 2,9% In the motion analysis of a catamaran without a bulbous bow, the heaving and pitching are more significant than a catamaran with a bulbous bow.