Interactive roll stabilization comparative analysis for large yacht: gyroscope versus active fins

The problem of the active stabilization of ship motions is particularly important in the case of pleasure boats or in any case of passenger ships, since the commercial value of the ship is directly related to the comfort of the load transported in this case “people”, considered as stresses induced on them by the vessel movements, with particular attention to roll, given the ship geometric characteristics. Naval architects developed trough the years different solutions to reduce the roll of the ship, and consequentially to increase the passengers comfort, and the development of this solutions followed the progress of technology. Active fins have been the most used, but now the gyroscope solution is coming out with interesting solutions also for large yacht with displacement over 1000 t. The paper aimed at making a interactive comparison between the two systems: active fins and gyroscopes, trough the case study of a yacht of 77.77 m, in order to evaluate if, assuming the same capability to reduce the roll for each one of the two systems, there are other advantages or disadvantages from the point of view of the naval architecture, in particular the resistance of the hull. In fact the importance of the resistance on high Froude number hulls, like planning hulls it is well known, but the paper aimed at giving result useful for naval architects also on traditional displacement hulls, like the one considered here, in order to give also a contribution for preliminary design. The interactivity of the process has been realized using not a theoretical estimation of the gain resistance of the ship according to equations etc. but real tank tests on the hull, according to International Towing Tank Conference methodology, with and without appendages.