The mass of water in the moonpool of a drill ship will be in linear, angular, and coupled motions influencing the moving ship. The water mass in the moonpool is subjected to sloshing and piston modes. These modes of movement of water mass sometimes lead to a larger quantity of green water on the weather deck causing downtime of the vessel in critical conditions. This paper discusses experimental and numerical study on moonpool with different cut-out angles facing the head on side of incoming waves. The study also aims at minimizing the water motion inside the moonpool under the response to the incident waves. It is concluded that the moonpool with cut-out angle configuration reduces the free surface elevation inside it in a considerable level. With the presence of moonpool on board ship, it is inferred that there is modification in damping, inertial and restoring components of loads and moments. © 2017 Informa UK Limited, trading as Taylor & Francis Group.