Additional Details ------------------------------ Bullet point: A pop-pop boat is a toy with a very simple steam engine without moving parts, typically powered by a candle or vegetable oil burner The name comes from the noise made by some versions of the boats. Other namei s are putt-putt boat, crazy boat, flash-steamer, hot-air-boat, pulsating water engine boat. Around the world they may be called can-can-boot, knatterboot, toc-toc, puf-puf boat, poof poof craft, phut-phut, or pouet-pouet Pop pop/ putt putt /phat phat boat is of tin metal.