The effect of bowshape on the seakeeping performance of a fast monohull

In the earlier publications on the Enlarged Ship Concept (ESC) attention has already been given to the possibilities of improving the seakeeping behaviour of a fast monohull significantly through a thorough change in the bowshape both below and above the stillwaterline. The aim of this bow modification was to reduce the nonlinear hydrodynamic forces in particular at the foreship. In the present study this has been taken one step further and the effect of a rather radical change in shape of the bow over some 25% of the length is studied. The behaviour ( i.e. heave and pitch motions) in both head- and following irregular waves of three systematic bowshape variations has been studied. Also the manoeuvring characteristics for these variations are investigated. Because one of the serious concerns about these proposed bow modifications lies with a possible increased sensitivity of the ships with the sharper and deeper bows to broaching in following waves, this aspect of the behaviour in waves has been studied also. The results of the comparison between these three designs (with this increasing change in bowshape) will be presented in this paper and the pro’s and con’s of the proposed changes in bowshape will be discussed.