Flying boat
The military value of flying boats was well-recognized, and every country bordering on water operated them in a military capacity at the outbreak of the Second World War. Flying boats such as the PBM Mariner patrol bomber, PBY Catalina, Short Sunderland, and Grumman Goose were procured in large numbers. The Sunderland, which was developed in parallel to the civilian Empire flying boat, was one of the most powerful and widely used flying boats throughout the conflict, while Catalinas were one of the most produced ASW of the war, with over 2,661 being produced in the US alone.