Ed and Oucho's Excellent Inventions - Series 1 - Mermaid Tail

Ed and Oucho travel the country making inventions from bits of old rubbish they find in the back of their van. They try to build the Mermaider, a mermaid tail for humans. It starts off well - until Ed realises that the mermaid tail they made from 13 pairs of flippers doesn't work at all. With the Big Big Cheese on their backs, will their general uselessness and lack of science know-how stop them from building the Mermaider in time?