[1] Like the slightly earlier Short Cockle, Satellite and Springbok, it had a duralumin monocoque fuselage of oval cross section.

[2] There was a direct reading fuel gauge above the tank, just in front of the forward cockpit, enclosed a in variety of fairings over the Mussel's lifetime.

[2] The performance of the Mussel on its first flight, piloted by John Lankester Parker on 6 April 1926 was disappointing, but the problem was traced to wing-root interference and solved with fabric root fillets.

It was powered by a 90 hp (67 kW) Cirrus III engine until August 1930, when it was replaced with a de Havilland Gipsy II.

[1] On its first flights[1] the Mussel I was configured as a seaplane, then spent a fortnight at the end of September 1926 as a landplane, appearing unsuccessfully in the Grosvenor Challenge Cup.

This pattern repeated through to the final accident; during that time the Mussel flew with floats for the Short Crusader Schneider Trophy racer and for the de Havilland Moth.

In that month a single long central float arrangement, similar to one built by Shorts for a de Havilland Gipsy Moth the previous summer.

[1][4] In its original form this undercarriage was amphibious, with main wheels mounted on a streamlined cross piece on the float, as on the Moth.

[5] In June 1932 the Mussel II began flying as a landplane again with a central single wheel undercarriage, with wing tip and tail skids.