An experimental investigation on slamming kinematics, impulse and energy transfer for high-speed catamarans equipped with Ride Control Systems

The operation of high-speed craft in large waves can produce significant vessel motions that lead to passenger discomfort and extreme loadings sustained by the hull structure during full bow immersion and wave slam impact. These large motions and loads can be significantly reduced by a Ride Control System (RCS). The influence of ride control algorithms on the motion and load response of a 112 m high-speed wave-piercing catamaran was previously investigated by the authors using a 2.5 m hydroelastic segmented model fitted with a ride control system. The present study extends this to investigate the influence of the control algorithms on the slamming kinematics, water entry impulse and energy transfer. The model ride control system comprised two transom stern tabs and a central T-Foil beneath the bow. In order to activate the model scale ride control system and surfaces in a closed loop system six ideal motion control feedback algorithms were developed: local motion, heave and pitch control, each in a linear and nonlinear application. These results were compared with the results with inactive but present control surfaces and with no control surfaces fitted. From these analyses it was found that the pitch control mode was most effective where in 60 mm model scale waves it significantly reduced the water entry impulse by 40% and the total strain energy by 90% when compared to a bare hull with no control surfaces fitted.