In order to investigate the mutual relation between the above water hull form and deck wetness, experiments are carried out with three models of which above water hull forms are different. Measurements of heave motion, pitch motion and the vertical acceleration at F.P. are performed in regular head waves and the wave steepness is varied. The behavior of the free water on the deck is recorded with a video camera. Measurements of absolute bow motion, relative bow motion and deck wetness in irregular waves are also performed. Results show followings. The effect of the above water hull form on the motion and the acceleration is small. The difference on deck wetness performace is not obvios, however the behavior of free water varies with the above water hull form. The long time experiment is needed to confirm the statistical property of deck wetness in irregular waves.