The story
The company was founded in 1956 by Major R.N. Gatehouse and Ronald Brookes who had formed a partnership the previous year to develop and manufacture a new radio direction finder (RDF) for use by private sailing boats.
Over the course of the 1950s, B&G, then based in Lymington, extended its activities into echo sounders and in 1960 produced its first speedometer.
The company has changed hands a number of times during and is now a brand of Navico, a Norwegian-based company in the marine electronics sector.
From Wikipedia’s article on B&G, shared under CC BY-SA 4.0.4