William Sisson and Co of Gloucester, specialized in the design and devolopment of high speed launch and marine engines and boilers and also designed vessels of all types, used initally on the Thames, Severn and Lake Windermere.
William Sisson had a strong interest in technical education, and the firm also became known for designing engineering equipment for educational purposes
1889 Established by William Sisson when he took over the small marine engineering works of J. J. Seekings and Co, situated near the Docks.
1896 Engine for SS Henley
1901 Manufacturers of stationary steam engines for marine use
1904 The business became a limited liability company. New works were built at Barnwood.
1908 Article in the American Machinist 'Design of an English High Speed Steam Engine' 
1917 Single-crank tandem compound engine. Exhibit at Bradford Industrial Museum.
1924 Appointed Mr A. Fleming Browne as their London representative.
1939 Engine for Swindon Gas Works
Post WWII Belliss and Morcom Ltd. began to take a financial interest in Sisson's
1958 Belliss and Morcom acquired full control of the company
Westonzoyland Museum Have a vertical engine and a high pressure/low pressure pair of high speed teaching engines.