Gonna be tough getting a 4S 5000 pack in that hull along with motor, ESC and rxcr. I have a BBY 20" off shore and have a Feigao FG5408408 motor/4761KV and will use a 2S pack for it. The motor was originally bought for an out rigger hydro from plans that was published in RC Boat Modeler magazine, that I never finished. For prop I have an Octura X445 and Grim Racer 42X55.
I would advise getting with the people at Off Shore Electrics . They also have a great forum for fast electric boating.
RC Boats by Offshore Electrics