Get a copy of the Lewis factors and use strip theory; typical Junior year hydrodynamics stuff. But that is kinda iffy for a NPL High Speed Round Bilge Displacement Series hullform at speed, lots of other hydrodynamics going on.
FWIW, this, and I bet most of your other ship motion questions, can be found in Dynamics of Marine Vehicles by Rameswar Bhattacharyya. There are online copies. Or else you could go to PNA by SNAME (1967 ed, not online) or Vol 2 of Basic Ship Theory by K.J. Rawson and E.C. Tupper (also online).