Improvement Of Motion Performance Of Small High Speed Catamaran

With the transformation of China’s consumer awareness, for the needs of personal purchase,home entertainment and special use,the small high speed catamaran is more and more popular. It has obvious advantages in stability, comfort, safety, construction technology and other aspects. So it is very important to research on this type of catamaran.Different from the conventional large catamaran, small high speed catamaran in wave motion response is very complex. Mainly because some vessels in high speed can enter sliding state; and due to the small amount of weight and higher speed, the small high speed catamaran sensitive to wave: hull lines, especially the bow type line’s minor changes may have a great influence on the motion performance, and navigation state will also have an impact on the ship resistance performance. This thesis focuses on the small high speed catamaran movement improve, especially the rapid optimization, and we carried out the following work:(1) To analysis the resistance characteristics of high speed displacement catamarans HWY45. At Fr < 0.84 speed range, vertical type bow column are tilted with respect to stem the drag reduction ratio for 11.8%-20%; At the Fr > 1.1 speed range, inclined stem is changed into a vertical type bow column, can effects drag reduction 6.0%-21.3% and in the ship design speed of 28 kn, vertical stem can be less 16.23% of the engine power reduction. And vertical stem catamaran sailing trim angle less than inclined stem, heave great, so vertical stem catamaran at high speed is close to floating sailing.(2) For sliding type high speed catamaran DYD286, due to the ways of promote will cause navigation attitude change, and the hull deviate from the optimal range of resistance. Through model test, analyzed the influence of different weight center of gravity(i.e. different propulsion mode) on the rapidity. At low speed, the front of the center of gravity has little impact on the total resistance; When in high speed, it will lead to increase resistance by 20.4%-47.3%. It shows that the change caused by the advance of the center of gravity lead, will lead to increase hull resistance and the power consumption of the host when in high speed. And put forward the improvement measures, so make the conventional propeller used in small catamaran is more feasible.