Abstract
Estimating added resistance in waves linked to ship speed drop and an increase of horse power is getting more importance with fuel price hiking these days. Calculated results of the added resistance based on the slender body assumption show good agreements with experimental data for slender ships. However, for practical ships there are many cases that calculated results do not agree with experimental data. Especially it is well known that in the short wave range the bluntness factor has a great influence. Then, to make the effect of a ship hull form on the added resistance clear, some investigation on the amplitude function (Kochin function) is described. And calculated results by the method using proposed amplitude function are compared with experimental data for the practical large blunt ship. As a result we have found out that the Buttock Line is also important in the short wave range as well as the bluntness factor.
