The roll motion of a fishing vessel with water on deck has been investigated from an experimental point of view. To this end, roll decay and forced roll in beam sea have been tested on a large scale model in the Towing Tank. The roll decay curves permitted to obtain informations about the roll damping. The comparison of forced roll without and with water on deck has been analysed in terms of modal analysis. It results that, in the investigated range of parameters, the effect of water on deck is a roll stabilizing one. An increase of roll amplitude, possibly dramatic, is to be expected in other frequency ranges and particularly in following sea condition.
