William Doxford & Sons (Engineers) Ltd., were one of the stalwarts of British shipbuilding, having a ship repair and construction yard as well as the engine business with which they built a reputation amongst ship owners that was to last over 70 years.
Doxfords built vertical, opposed-piston two-stroke diesel engines for ships, up to 8000 bhp, and their design became a standard unit for British flag-carriers until the licence-built Sulzer and B&W engines challenged their position in the early 1960's. The single-crankshaft engines had connecting rods for both the lower and upper pistons, with two rods for the upper piston. It is completely different to the Junkers opposed-piston design, as the upper pistons are connected to the single crankshaft by connecting rods each side of the main cylinder. Doxford Layout This system had inherent advantages over the standard four-stroke engine, as the two-stroke running enabled a low operating speed (115 rpm), thus eliminating the requirement for a reduction gearbox between the engine and propeller, and as the engine was reversible, no reverse gear was required.