The wire-braced wings were of an unusual elliptical layout, with the maximum chord and thickness at mid-span on each side, tapering in towards the root.

The rear of the elliptical section fuselage was also wooden, being a monocoque construction with two layers of mahogany veneer applied over a frame of spruce formers and stringers.

The twin floats, made of duralumin, were each carried on a pair of streamline section raked struts, braced by wires.

[4] The aircraft was completed by 18 April 1927, fitted with a derated engine producing 650 hp (480 kW) and wooden propeller for initial testing.

Initial flight testing was made by Bert Hinkler, who asked Shorts to enlarge the aircraft's rudder area before he attempted to fly it.

Hinkler reported that the aircraft suffered from severe hunting at full throttle, admitting that he had been wrong about the rudder area.

Webster, who reported its flight characteristics to be pleasant, although the engine still tended to cut out: this led to some alarming episodes when the aircraft was later flown by Flying Officer H.M. Schofield.