The Walrus amphibious reconnaissance aircraft were designed by R. J. Mitchell of Supermarine Aviation Works. They were meant to be launched from ship-borne catapults, and they were the first such amphibious aircraft in the world while carrying a full military load. In 1935, Walrus aircraft entered service with the Royal Australian Air Force under the Seagull V A2 designation. On 16 Mar 1936, they entered service with the British Royal Air Force. In the same year, the New Zealand division of the British Royal Navy also received them. By the time the European War began, they were in widespread use. During the war, they were credited with sinking or damaging at least five German submarines and rescuing many downed airmen. The Irish Air Corps used them during the Irish Emergency period during WW2 for maritime patrol. After the war, one Walrus aircraft, HD874, participated with the Australian Antarctic Expedition in 1947. A total of 740 Walrus aircraft were built. They were built in three major variants. The original metal hull variant was designated Seagull V, the second metal hull variant was designated Walrus I, and the wooden hull variant was designated Walrus II. Some of the nicknames for the aircraft include “Shagbat” and “Steam Pigeon”.