In this paper, speed increasing performance is compared by calculation for two cases which is boosted by open cycle gas turbine (G 2 type) and by high speed diesel engine (Kawasaki MAN VV 22/30). In each case, ship is designed suitably but independently. Their particulars are shown in Table 1, Table 2, and details of calculation are shown in Appendix. Assumed the power increasing performances of main and boosting engine as Fig. 1, the speed increasing processes of each ship become as Fig. 3. From these results, we can conclude as follows, 1. Diesel ship has greater advanced distance than gas turbine ship for same interval.(Ref. Fig. 5) 2. The shorter the time necessary to raise the power of gas turbine, the better the speed increasing performance of gas turbine ship. 3. In design of shafting system, the great torque fluctuation caused only in tubine ship must be considered elavorately. Conclusions mentioned above are made for ship of displacement type that is 360^T and 420^T, however, they are not all applicable for ship of hydroplane type smaller than 100^T.
