This is an American heavy cruiser "The Salt Lake City". It has a very interesting history; built in 1926 it served in WW2 and was involved in the Pearl Harbour saga.
I managed to get hold of the design details and drawings to build this ship. It has a solid hull of foam with cut outs to take the electronics, motor and rudder servo.
It floats well and is radio controlled. Note the observer biplanes used for reconnaissance.