That looks like a fake Sub. It seems to be a typical english Narrow Boat converted by somebody with a good sense of humour into something that looks pretty funny. We had some of those funny chaps in Hamburg too. One morning a big Submarine appeared on the Alster (Lake within the city of Hamburg). As powered boats are not allowed on this lake (except tourist boats), the police showed up and tried to arrest the Submarine Commander. Thats what they found: A man powered piece of plywood . And totally legal ! Nice joke, I must say.