The PBY Catalina is the world's most famous and widely used flying boat in the history of aviation. With its characteristic droplet-shaped weapon bays on the sides of the hull and self-sealing fuel tanks the PBY became the U.S. Navy's standard reconnaissance aircraft from 1941 onwards. An endurance of 24 hours at cruising speed was possible with this aircraft. In addition to long-range reconnaissance and convoy protection, the PBY was primarily used to hunt submarines and surface ships and attack them with depth charges or torpedoes. The PBY-5A made its maiden flight on 22 November 1939 and the first amphibious Catalina was delivered in 1941. PBY flying boats were used for maritime surveillance, submarine hunting and search and rescue with the US Navy, the Royal Navy and the naval air forces of Australia, New Zealand and Canada, the Netherlands and the Soviet Union until the mid 1950s. With a total 3272 examples it is the most prolific flying boat of all time. Over 1400 were built as PBY-5A and -6A amphibious versions. Later a batch of these aircraft were converted to fight forest fires.