Vic Smeed was thinking cardboard when he designed the sailing yacht Krispie. You need quite a few cornflake packets for that one.
I ended up after an auction of deceased members models with a small warship, looked quite good. ran it a few times it is quite small and runs on twin servo motors.
A friend helping had another similar one. He said he left his in the water and it started to come apart! Seems the builder used sticky brown paper onto a balsa frame.
However it might have been better to have waterproofed the frame before putting on the sticky stuff. Left mine on the shelf after that. Also found that with one esc, one of the motors usually the same one would not start without a flick, then OK.
Roy