The Short S.7 Mussel was a single-engined two-seat monoplane built by Short Brothers to test the performance of their duralumin monocoque floats. Two were built.
Short Mussel II, Felixstowe, June 1929
The Short S.1 Cockle was a single-seat sport monoplane flying boat, with a novel monocoque duralumin hull. It was underpowered and so did not leave the water easily, but it proved that watertight and
Cockle on the River Medway, Rochester in 1924 - original fin