An Austro-Daimler-powered Bat-Boat takes off.

The other known Salmson-powered Bat-Boat was purchased by Germany. It was flown to that country in late May 1914 by Wilhelm Hillman and was given the German naval serial 44.

The Austro-Daimler-powered Bat-Boat which visibly wore the number 38 was delivered just before the Admiralty redesignated the RFC's Naval Wing as the Royal Naval Air Service, it is seen here in early August 1914 at Felixstowe, where it was briefly stationed before going north to Scapa Flow.

As neither this photograph (taken at Woolston) nor the one at right (taken at Calshot) bears a date, it is uncertain which was the earlier; but, as suggested in the text, it seems possible that the fin and rudder were at one time inverted in an attempt to improve directional control.

The Sopwith company’s impressive exhibit at the 1914 Olympia Aero Show, which opened on March 16, was this Bat-Boat of the larger type, fitted with a 200 h.p. Salmson (Canton-Unne) water-cooled radial engine.

This Sunbeam powered Bat-Boat, one of two Sopwith aircraft entered for the 1914 Circuit of Britain seaplane contest, was photographed at Woolston. To provide clearance for the Sunbeam’s large four-bladed propeller, the wings had to be raised above the hull to the extent seen here.

One of the Salmson-powered Bat-Boats beside the Pemberton-Billing shed at Woolston.

The 1914 Circuit Bat-Boat, seen here at Calshot Naval Air Station, was allotted the official serial 879 on being acquired by the RNAS. In this view the basic outlines of the balanced rudder and the fixed fin may be seen.

Sopwith design for gun-carrying Bat-Boat (100 h.p. Gnome Monosoupape)

The Bat-Boat configuration was revived in the Royal Aircraft Factory C.E.l of December 1917. The first of two prototypes, N97 had a 230 h.p. RAF 3a engine.

The second C.E.l had a 260 h.p. Sunbeam Maori engine. In the C.E.l the pilot and observer sat in tandem, and the single-step hull differed markedly from the Bat-Boat hulls.