Jack Craib's Rowboat Motor Information Site

Watermota
Pembroke Engineering Works
Hampton Wick, Kingston upon Thames

The current Watermota Company's website gives a succinct history. They aren't interested in going into details or sharing early photos though!
The early history is this:


 

"Watermota was established at the Pembroke Engineering Works at Hampton Wick, Kingston upon Thames in 1911 by Walter Fair as a subsidiary of Rigbys, a London gunsmith, where he was the manager."

"The first engines produced by the company were American Waterman two stroke inboard and outboard engines built under licence, similar in appearance to the copper jacketed K1 and K2 engines which were eventually developed by Fair."

"During the First World War, the British Admiralty approached Watermota to design and produce an outboard for their use, the result being the Mark 1 which was produced with little change until 1926 when it was developed for outboard racing for Fair’s son Colin and Shingo Yano who had previously worked for the Anzani engine company."

When WWI ( August 1914 to November 1918) first mobilized British manufacturers to support the war effort, the Watermota production facilities were greatly given over to making Hyland Cocking levers for machine guns and a range of aircraft fittings. When the Admiralty request came through they didn't design a new motor. They produced a copy of the Waterman 1916 3.5hp single which was named Watermota. From that design they went on to develop later outboards. (This is how I interpret what I read. E.C.)