Maneuverability of <i>C<sub>b</sub></i>-Series Full Hull Ships

Abstract

Maneuvering simulations for full hull ships were conducted by the MMG model, which is one of a maneuvering simulation method, based on the hydrodynamic force characteristics obtained in the captive model tests presented in previous paper1), and compared with the free-running model test results. The purpose of this study is to investigate the applicability of the MMG model to the full hull ships with very large block coefficient. We found that the original formula for longitudinal velocity component to rudder (uR) in the MMG model is not well working in case that the block coefficient (Cb) is very large as Cb = 0:87. To settle the problem, an improved formula of uR proposed by Yoshimura et al.3) was used and it was confirmed that the formula can capture the behavior of the rudder normal force just after steering better. Turning and course keeping performances in fullscale ships become worse comparing to those in ship model due to the worse rudder force performance comes from smaller propeller load in fullscale. Although the level of the worse turning performance is not so serious in fullscale, there is a possibility that overshoot angle of zig-zag maneuvers is over the IMO regulation for the present ship with Cb = 0.87.