World War 2, Western Australia, Rottnest Island, Thomson Bay, HMAS Sydney Walrus, 1938

The Supermarine Walrus was a British single-engine amphibious biplane used as a maritime patrol aircraft; it was the first British squadron service aircraft to incorporate a fully retractable undercarriage, fully enclosed crew accommodation and a fully metal fuselage. Designed to serve as a fleet spotter launched by catapult from cruisers or battleships, the Walrus type first flew in 1933.