Analysing correlations among resistance at Froude number F_∇ (= V /√ ∇ ^1/3 g ) =3.5, trim angles at F_∇ =2.5 through 3.5, by using model test data in still water of the high speed craft, the clear correlation was found to exist between resistance at F_∇ =3.5 and trim angle at F_∇ =2.5. Therefore, the sequential unconstrained minimization technique was first applied to get the smallest total resistance hull form for each 30 minutes interval of trim angle change, and then followed the discussion concerning deviations arisen and resistance performance due to obtained hull form parameters. Using diagrams related to the total resistance at F_∇ =3.5 and the trim angle at F_∇ =2.5, we clarified finally the influence of the unit trim angle on the total resistance coefficient within high speed range.