Kids playing up after two days in port? Game-boy’s batteries flat? Good. Set them the task of designing and building a yacht that will sail across the harbour. This one was created from a polystyrene dish that came from a Breton fishmonger with a plat de fruits de mer. The ballast is water in a supermarket bag, the mast a piece of junk and the rigging is made of twisted duct tape. The sails are superbly cut from a copy of The Salisbury Journal, but the trick that conferred vital directional stability was the centreboard. This was fashioned from a strip of baked-bean can flattened and shoved through the bottom, well abaft the centre of lateral resistance so that it kept her going straight, even downwind. A lesson there for many a designer, especially the rather large child who built the good ship Fiasco.