ON THE TWIN-HULL SHIP ( NO. 1 )

As is well known, the resistance of a ship can be divided into frictional and residual parts. Wave-making resistance, which comprises most of the residual resistance, changes with speed in a complex manner due to the interference effect of ship wave systems, hence the characteristic humps and hollows. For a twin-hull ship, the change in wave- making resistance becomes even more complex. It is conceivable that the reduction in wave-making resistance, which can be brought about either by a favorable interference effect or by a reduction of beam of a hull by dividing the required displacement into two hulls, could offset the increase in frictional resistance. But a satisfactory conclusion on wave-making characteristics is lacking. Currently, at the ship propulsion division of the Transportation Technical Research Institute, Japan, merits of twin-hull ships are under study. One phase of that study, theoretical calculations and experiments, has now been completed and the results are presented herein.