Cobblestone effect on SES

Wve induced vertical accelerations (cobblestone oscillations) of a SES in small sea states is studied. Resonant spatially uniform and nonuniform dynamic cushion variations arethen important. A nonlineartime domain solution is used. The nonlinearities are mainly due to the flexible stern seal bag behaviour. It isd demonstrated that both the spatially varying pressure underneath the flexible stern seal bagand the impact between the bag and the water are important for the vertical accelerations of the vessel. The influence of main par ameters characterizing the stern seal bag is discussed.