Contents

1 Introduction

2 Foundation and History of the Company

3 Early Engines

4 Later Engines

5 The Manufacturing Process

Introduction[edit]

Foundation and History of the Company[ edit

The Manufacturing Process[ edit

Born on 1 March 1812. William Doxford the son of Joseph Doxford and Elizabeth Chapman.By 1840 at Cox Green he started to build wooden ships. In 1857,William Doxford moved to Pallion in 1857, where he began operation on a much larger scale. In 1870. a larger site was purchased and five new berths were laid down.Two years after starting operations at the new site, he received his first Admiralty order, for three composite auxiliary steam gunboats. In 1875 Doxford commisioned a composite screw corvette for the Navy. The Magician.William Doxford and Sons began building marine steam engines in 1878, when the original engine and boiler works were constructed. The first engines were compound, triple, then quadruple expansion.In 1887 they built a single screw torpedo boat, which attained a speed of 21 knots, the highest speed recorded for that type of vessel. It ran her trials with a coal burning locomotive boiler, but was shortly afterwards converted to oil-burning and ran several successful trials on this new fuel. It was however long before her time, and was sold to a private owner.In 1902 the original five berths were scrapped to make room for three berths of greater length and breadth, which enabled the firm to build vessels up to 540 feet in length and of 20,000 tons capacity.The company was founded in ..... and .....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.William Doxford and Sons began building marine steam engines in 1878, when the original engine and boiler works were constructed. The first engines were compound, triple, then quadruple expansion, and later still turbines. In 1887 they built a single screw torpedo boat, which attained a speed of 21 knots, the highest speed recorded for that type of vessel. It ran her trials with a coal burning locomotive boiler, but was shortly afterwards converted to oil-burning and ran several successful trials on this new fuel. It was however long before her time, and was sold to a private owner.In 1906, Doxfords began to consider the possibilities of the diesel motor for ship propulsion. They realised the solution lay in experiment and research and after a series of experimental engines was built and tested, emerged the single cylinder 450 HP engine. Not satisfied with the success achieved, they decided to experiment, with a 3,000 HP four cylinder single shaft set. These experiments had to be put on hold due to the outbreak of the First World War however during the next four years Doxfords built 21 destroyers and engined them with turbines each of 27,000 HP.When the war ended they resumed work on the four-cylinder engine, and after further research and the completion of successful trials it was felt justified in putting this into production. So in 1921 the engine was installed in the Yngaren' this was the first motor ship to be built by Doxfords. From that day on the name of Doxfords became world famous, a total of £100,000 had been spent on developing this new engine. A further five units were built during the 1920-23 depression.Doxfords continued with research and development, overcoming problems of vibration. Then during the grim thirties' when hardly a keel was laid in Sunderland yards, important changes took place in the design and construction methods of the engines. Using steel welded fabrications of the superstructures and supporting frames obtained substantial size and weight reduction. Cast-iron bedplates were still in use until 1936 when fabricated construction was extended to these also. At around the same time Keller and Gebbie collaborated to introduce the Doxford Economy Ship. These and the "Improved" economy ship began with ship No. 612 and ended with ship No. 664. The first Doxford Economy Ship was the MV Sutherland. http://www.shipsnostalgia.com/guides/MV_Sutherland During World War Two they turned their whole production over to a three-cylinder 2,500 bhp unit. It later earned the title of the economical'; because of its low fuel consumption, only six tons a day. Ships with heavy loads had to run this engine at or near to its limiting rpm to keep up with a convoy in the North Atlantic. In spite of this abuse, they remained remarkably reliable. It remained in production after the war.In 1947 Purdie being a shrewd Scotsman attracted engineer Percy Jackson to Doxfords. This when competition for higher engine powers were being demanded. Also turbo-charging of the big two-strokes was just ahead and further development of the very successful Doxford (LB) engine would have to be undertaken, if it was to hold its position and keep the firm and its licensees well occupied with Doxford engine orders.Jackson developed turbo-charging and the common rail system of airless-injection. Jackson set about retaining the high economy of the original arrangement while achieving greater simplicity and lower costs.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. 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.A milestone in Doxford engine technical development was the design, construction and testing of the Seahorse prototype medium speed engine between 1970 and 1975. This was a joint venture between Doxford's and Hawthorn Leslie (Engineers) Ltd of Tyneside. It was intended to offer the marine market a crosshead engine, with its associated robustness and ability to burn Doxford-Hawthorn 58G4 Seahorse Engine heavy oil, which was capable of being geared down to suit the low rotation speeds (80 to 100 rpm) of the very large propellers then being fitted to turbine driven super tankers. In this, they were responding to competition from the established trunk piston medium speed engine builders, as well as creating the possibility of entering the electric power generation market. The prototype Seahorse built upon the fundamental design principles of the J' type engine. The opposed piston configuration's inherent internal mechanical balance, and hence freedom form vibration problems, coupled with exceptionally unrestricted scavenge air flow through the cylinder, with its potential for superior turbo charging, all allowed for a rotational speed of 300 rpm. By comparison, the operation speed of a conventional Doxford J' type engine, and indeed of its direct drive crosshead engine competitors was in the region of 115 rpm to 124 rpm. The Seahorse engine achieved a remarkable power output of 2,500 horsepower (1850 kW) per cylinder. A schematic model of the Seahorse engine in the TWM collection bears the designation58G', implying the achievement of a further significant stage in the evolution of Doxford engine design the G' (for Geared') type. While no Seahorse engines were ever built commercially, many of the design features were incorporated later in the 58JS3 engines. In fact the 58JS3 was more or less a slow speed Seahorse.The following views of the Doxford Engine works between 1957 and 1958 have been supplied via The Doxford Friends Association and member Averheijden from an album lent to the society by Jim Duncan in 2003