Optimal Bulbous Bow of Gooseneck Shape for a Passenger Ship in Restricted Speed Range

초록

With the recent rising fuel costs resulted from the rapid increase of oil price for several years and strengthened regulations on CO2 emission resulted from the global warming, there is an increasing interest in the resistance performance of a ship. Recently, the change of bulbous bow by taking into account of actual operating speed, draft, etc has been in the spotlight as a very useful fuel saving method, and among which, the changes in small draft was specially considered for a passenger ship and gooseneck bulb has been applied in Europe and other areas for the purpose of maximizing the wave resistance. This study performed an optimization by considering the range of operating speed, by using the regression equation that can be used to measure the resistance performance of a passenger ship with gooseneck bulb. The objective function is a numerical value that added up the pressure resistance coefficient estimated by speed and as limiting condition, this study set the changes in pressure resistance coefficient by speed in order to prevent pressure resistance from increasing rapidly at a particular speed. This study compared the added resistance with the sea worthiness in a ship with reference hull and gooseneck bulb applied and found that there was no difference between reduction in speed of a ship and comfort sailing in two waves, and based on this, verified the applicability of gooseneck bulb into an actual passenger ship.