10 th Naval Platform Technology Seminar 2005 260 EFFECT OF BULBOUS BOW ON MOTION OF SHIP: PHASE I M. R. Islam Assistant Professor Department of Naval Architecture & Marine Engineering (NAME) Bangladesh University of Engineering and Technology (BUET) Bangladesh rafiqis@name.buet.ac.bd Zobair Ibn Awal Undergraduate research student Department of Naval Architecture & Marine Engineering (NAME) Bangladesh University of Engineering and Technology (BUET) Bangladesh Himani Mojumder Undergraduate research student Department of Naval Architecture & Marine Engineering (NAME) Bangladesh University of Engineering and Technology (BUET) Bangladesh SYNOPSIS It is not very long that the great Tsunami had struck the shores of South Asia. A lot of disaster had happened particularly in the field of marine industry. Numerous numbers of ships could not survive this natural calamity. After this incident a large number of search and rescue vessels are needed. Theses vessels require a great deal of stability, safety and speed. With this view in mind, this paper investigates the behavior of motion incorporating different shapes of bulbous bows. It is a generalized fact that the lesser the amplitude of motion the better the resistance, human comfort and ship stability. A number of researches had been done in studying the resistance characteristics incorporating different bulbous bows. But the effect of bulbous bow on motion had not been studied in detail. In this paper some work has been performed by incorporating various types of bulbous bows. Different types of bulbous bows were designed in three-dimensional (3D) computer aided design (CAD) software. The vessels with their new bows were paneled. A C++ computer program is developed for this paneling purpose. With these new designed bulbous bows the motion characteristics are studied using 3-D source distribution technique in regular wave. It is observed that the bulbous bow influence the motion responses of vessels. 1. INTRODUCTION Today the bulbous bow is a normal part of the modern sea going vessel. As model experiments show, a ship fitted with bulbous bow can require far less propulsive power because of reduction in resistance and have increased cruise speed; which gives an overall reduction in fuel consumption [1]. The bulbous bow was discovered rather than invented [2]. Before the turn of the century, towing experiments performed in the US with warships established that the ram stem projecting below the water had a resistance decreasing effect. A torpedo boat model showed that an under water torpedo discharge pipe ending in the forward stem also reduced resistance. A flat board, intended to suppress the bow wave, was fitted by W. Froude [3] to a model of H.M.S. Fury in 1873, "with benefit to the performance". Many clipper ships of the 1850's sailed at speeds where Froude number (Fn) exceeded 0.33. The designers learned that fining