A simple method for generating the dummy hull-form was introduced in order to apply the Bayesian wave estimation method to actual merchant vessels. It is very difficult, however, to obtain the detailed hull-form of the vessels nowadays. Using the dummy hull-form data, wave parameters are estimated by using the Bayesian modeling procedure. In order to examine the proposed method, the estimated wave parameters were compared with the measured data of a radar wave observation system. It was confirmed that the dummy hull-form for the merchant vessels can be used for Bayesian wave estimation with reasonable accuracy.
To reduce the GHG (Greenhouse Gas) emissions from shipping, weather routing or "just in time routing" is considered as one of the effective operational measure. For the same purpose, fuel economy indicators for ocean transportation, so called "10 mode at sea" (Sasaki et al., 2009), are tried to be established in Japan. Simple and accurate methods for estimating the directional wave spectrum around the ship are needed to evaluate the actual fuel efficiency and to develop the navigation guidance systems. Several on-board guidance systems have been developed in the recent past (e.g. Iseki and Terada, 2002). One of the most important problems for the systems was to get information about directional wave spectra. Based on the assumption of linearity between waves and ship motions, some studies tried to estimate directional wave spectra using ship motion data (e.g. Webster and Dillingham, 1981). In other words, these studies tried to solve an inverse problem of how to estimate the input from the measured output data. Nowadays, however, it is very difficult to get the body plan or the off-set data that represents the hull shape in detail. That is the most crucial problem for the actual application of on-board guidance systems to merchant vessels.
