Short S.18 Knuckleduster Flying Boat

The Short S.18 Knuckleduster was a British twin-engined, flying-boat designed and built by to Air Ministry specification R.24/31 for a “General Purpose Open Sea Patrol Flying Boat”. The contract also specified the use of the experimental Rolls-Royce Goshawk engine. The Saunders-Roe London and the Supermarine Stranraer competed successfully for this contract.