In my opinion, early flying boats are a thing of beauty and this Russian built Grigorovich M-15 is no exception. It is the only surviving example of the 80 built and is c/n R.11C.262 It is on display in the 'WW1' hangar at the Muzeum Lotnictwa Polskiego. Krakow, Poland. 23-8-2013.

It's history is given in the following info taken from the museum website:-

"Since 1911, the Russian Imperial Navy employed French-built seaplanes (i.e. Farman, Borel and Léveque). The maintenance of the aircraft was performed at the S. S. Shchetinin & M. A. Shcherbakov Works in St. Petersburg. Since 1913 the works had been led by Dmitry Pavlovich Grigorovich. In the same year he designed, based on French originals, a successful M.1 aircraft with a boat-like fuselage. This was the beginning of a family of light flying boats, which served with distinction during the First World War.

In Autumn 1915 the Imperial Russian Navy issued an order for a heavier flying boat intended for long-range reconnaissance. In December 1915 Grigorovich built the M-9 type, which first flew on 9th January 1916. Notably, on 17th September 1916 the M-9 became the first flying boat to perform a loop, piloted by test pilot Jan Nagórski. A serious weakness of the design, however, was the licence-built Salmson-Unne radial engine. Therefore, in 1916 an improved variant designated the M-15 was built, powered by the excellent Hispano-Suiza V8 engine. Only 80 M-15 machines were built.

The Grigorovich M-15 was a long range flying boat biplane with the wing canopy placed over the fuselage, a pusher propeller and the empennage placed on a pylon, in the propeller's air stream, which increased the steering efficiency. The semi-monocoque wooden construction was covered with stressed plywood skin attached to open work formers. The wings and empennage were made of wood covered with fabric. Two stabilising floats were fitted at the ends of the lower wing.