Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 148,470 pages of information and 233,895 images on early companies, their products and the people who designed and built them.
of Limehouse, London
1884 Made 30 nhp 2cyl compound steam engine for 37 grt tug built by Joseph S. Watson, Blackwall. G S de Ritter, Limehouse. 
1900 Walter Henry De Ritter inherited the business, which produced marine engines, general engineering plant, and the complete machinery necessary for the preparation and manufacture of tea lead, white lead, Edwards' air-pumps and condensing plants.
1923 Advert: 'W. H. De RITTER & CO., Ltd., ENGINEERS, THREE COLT STRET, LIMEHOUSE, E.14. ESTABLISHED 1850. On Admiralty, Air Force and War Office Lists.' 
A hand-operated winch by G. S. de Ritter, probably off a ship, was seen in a reclamation yard in Somerset in 2010.