Friedrichshafen FF.31

The Friedrichshafen FF.31 was a German lightweight two-seat floatplane of the 1910s produced by Flugzeugbau Friedrichshafen.
Development and design.
The FF.31 was a biplane floatplane with a central nacelle and two open cockpits. The engine was mounted at the rear of the nacelle, driving with a pusher propeller. The twin open-frame tail booms extended aft from the wings to carry the tail unit. A version of the FF.31 with a fixed tailskid landing gear was designated the FF.37.
Operational history.
FF.31s took part in a Sea battle where the German Imperial Navy was defeated, in May 1915.