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Doxford Engines 1878 - 1980

21 Knot Torpedo Boat 'Elrayo'
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.

Doxford Turret Ships

Triple Expansion Engines

Between 1892 and 1911 Doxfords built one hundred and seventy six turret ships. Six more were built by other yards using Doxfords design; Swan Hunter built three, Hawthorn Leslie built one and Vickers built two at Barrow. Most had Doxford triple expansion steam engines fitted. The turret ship design was part of the transition from sail to steam propulsion. The Suez Canal , telegraph, steam power, and steel ships had all recently contributed to a revolution in merchant shipping. The British Empire , the need for British coal to fuel the emerging use of steam as motive power, the world over, helped Britain to exploit the potential of new ship technology. The turret ship arrived at a time when there was need and an opportunity for improved performance of ship and cargo handling. Doxford shipyard and adjoining engine works were ideally placed to benefit doubly from the new design.

The Scottish captain Alexander McDougall patented his whale back steamer designed in the late 1880s and built them at his shipyard in Dulluth , Minnesota . With an almost cylindrical hull, and flush hatches they also had raised turrets to support the accommodation and deck machinery. Doxford's ship No. 217, called TURRET was the first turret built by them in 1892. This was followed by a whale back steamer, The SAGAMORE , ship No. 218 under licence from McDougall in 1893. Other shipbuilders offered variations of the turret design.

Doxford turrets differed from the whaleback in the style of the turret. The whaleback had individual turrets positioned along the deck, while the Doxford design had one continuous turret. Despite differing in construction the term 'turret' was retained by Doxfords. The ships varied in size from the smallest 691 G.R.T. TURRET HILL, to the largest 7703 G.R.T. QUEDA.

Turret Ship
S.S Newbiggin c365 1906

Some controversy surrounds the patent taken out by Doxfords for the ships design. The design was that of Arthur Havers , a chief draughtsman employed by Doxfords. Having presented the design to Doxfords, he proposed to apply for patent rights, only to find that the following day Doxfords had already done so, in their name. Havers took Doxfords to court and was awarded £1,250 for the loss of his patent. His rifts with the company led to him develop the MONITOR ship at Osbourne, Graham & Company at South Hylton , some two miles up-river from Doxfords.

A detail account of the Doxford Turret Ships is in a book by Gray & Lingwood, published by the World Ship Society in 1995, ISBN 0 9500044 6 4

Launch of H.M.S 'Opal' 1915.
The first twenty-five years of the twentieth century of the Doxford marine heavy oil engine could broadly be called the Keller era. It was a period of success, consolidation and expansion. Karl Otto Keller was followed by his assistant William H. Purdie a marine engineer, and director but not a designer in the creative sense. Although it was acknowledged that the Doxford works and licensees were very busy producing engines, and Purdie was kept fully occupied. Keller was a supreme example of the creative engineer. 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.

'The Economical'
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.

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.

Model 6 Cylinder LB 1951
In 1947 Purdie being a shrewd Scotsman attracted Percy Jackson to Doxfords just when higher engine powers were being demanded. Also turbo-charging of the big two-strokes was just ahead and further development of the hitherto 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.

Early problems tackled by Mr. Jackson were with the turbo-charging and the Doxford engine common rail system of airless-injection had been most efficient. Jackson set about retaining the high economy of the original arrangement while achieving greater simplicity and lower costs. This he did with no great expenditure of time or money and not without departing drastically from what Doxford customers knew and liked, a very important consideration in marine engineering.


Doxford 'P' Engine on Test
The next phase was an entirely new range of Doxford engines the 'P' class. Doxford engines were limited to six cylinders as this was considered to be the maximum number that could be used working on the opposed piston principle, due to torsional vibration problems imposed by the comparatively flexible crankshafts employed in this design. This flexibility was overcome to a large extent in the 'P' range of engines by making the crankshaft more rigid, using a very large overlap of the crankpin and bearing journals and also by reducing the throw of the side cranks with the use of large diameter main bearing journals.

The new engine eliminated some of the design elaboration, of the original (LB) type, it saved on length and had a stiffer crankshaft. Percy Jackson was able to offer Doxford engines with appreciably higher power than had been thought possible, although six cylinders were regarded as the upper limit. The design was a success and gave great satisfaction to a lot of owners.

Doxford Design Team

Though the development of the 'P' engine was successful, the demand for increased power had continued. Once again the Doxford engine was feeling the keen competition. The fact was that it could not compete in the big single-screw diesel engine business. So once again in 1962 Percy Jackson demonstrated his resourcefulness. The result was the quickly designed and rapidly developed the 'J' type Doxford engine. By adopting disc-type crank webs and using them as main bearings that proved in prolonged testing the Doxford has acquired a fundamental ability to cope with very much higher powers than was thought achievable.

The general design was clever and simple and the final result was a high-powered marine oil engine that was keenly competitive. Doxfords consider it to be the lightest engine of its type
M.V. North Sands Leaving River Wear 1965.
available, and the cost per BHP is closely related to the specific weight. The pro-type a nine cylinder 20,000BHP was installed in the M.V. NORTH SANDS a 64,500 ton tanker. The confidence in this new and untried design was unprecedented at the time and reflects the high repute in which the name of Doxford and Percy Jackson was so widely held. No finer endorsement and value of his work in the oil engine sphere could have been given to Percy Jackson than to have two engines named after him the 'P' and 'J'.

The Doxford-Hawthorn Seahorse Engine

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 designation '58G', 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 Doxford 58JS3 Engine

Doxford 58JS3 at Beamish.
he last new Doxford engine design, which was known as the 58JS, was in response to the escalating fuel costs. The 58JS engine was developed to provide compact direct drive machinery for smaller ships which could then run on cheap low-grade heavy fuel oil. The piston stoke was shortened from that of the normal 'J' type engines to enable a faster speed of 220 rpm. Reliability at this higher speed was achieved through technology derived from the Seahorse project. The power output was 1,830 horsepower (1,350 kW) per cylinder, a considerable advance on the conventional 'J' type engine with the same cylinder.

Design work on the 58JS engine began in the autumn of 1976. Among the people at Doxford's who were responsible for the concept and development of the 58JS design were Frank Butler, Henry Henshall, George Jackson, Finn Ørbeck, David Stables and Brian Taylor. Along with many other people, working on the detail design of the components.

The Last Doxford Engine
It was intended to offer 58JS engines in three, four, five and six-cylinder units; production of engines with larger diameter cylinders was also envisaged, using the Doxford standard 67cm and 76cm cylinder bores. However, the only engines to be built were then three-cylinder 58JS units.

Construction began in 1977, and the first engine completed its test-bed trials in 1978. Seven of the ten engines were supplied to ships. These vessels were equipped for unmanned engine room operation, and they represented the first application of microprocessor systems to the automatic control of slow-running marine oil engines. Of the seven ships equipped with 58JS engines five still appeared in the Lloyds register, 2002-2003 edition.

The last engine built at Doxfords in 1980 was a 76JC4R. It was fitted in the ship "Canadian Pioneer" which was built in Canada. This vessel is now named "M.V.PIONEER" and is owned by MARBULK CANADA INCORPORATED and managed by V-SHIPS U.K. LIMITED.

The Doxford 58JS3 Marine Oil Engine and The Doxford Engine Friends Association.

A Brief History of the Doxford Engine

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