My son had a hobby shop and was involved in radio controlled boats, planes etc. He bought a set of plans for the 'cracker box' boat and we built a 'plug' (which we still have) from which we made a mould for making fibre glass models. He used a 'genoa' moter which I think is a modified whipper snipper motor. He achieved speeds up to 60 kph. Timed with the help of a friendly police officer with his radar gun. The cracker box is regarded as a pure drag racer and does not turn well at high speeds. He had another boat which was about 5 feet long, we still have the mould for that hull. The major problem was finding a convenient stretch of water to play on.
Well proportioned women live longer than men who comment on it.