A vessel, especially a drillship, provided with a moon pool

The invention relates to a vessel, especially a drillship or so-called drilling ship. The vessel comprises a hull having a bottom surface and a deck. Said vessel is provided with a moon pool, which extends from said bottom surface of the hull in an upward direction through the hull. Further, said vessel is provided with a cavity located at a rear side of the moon pool. Said cavity is at least partly open at a front side to allow water to flow from said moon pool directly into said cavity. Further, said cavity is at least partly open at a bottom side to allow water to flow out of said second cavity. The cavity is defined at least partly by means of a trailing wall sloping downwards in a rearward direction and at least partly by means of a ceiling connecting a rear wall of the moon pool with said downwardly sloping trailing wall.