floats. Performance was generally satisfactory but improvements were made and the machine was rebuilt with new wings, metal floats and a 169 hp Armstrong Siddeley Mongoose engine. Tests both on the sea and in the air showed that designer, Harold Bolas, had met the requirements and it was officially judged to be exceptionally good. The aircraft was launched using a compressed air catapult mounted on the forward casing of the submarine and recovered using a crane. HMS M2 was a Royal Navy ...