
The Doe Triple-D or Doe Dual Drive is a make of
tractor
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a Trailer (vehicle), trailer or machinery such as that used in agriculture, mining or constructio ...
produced by Ernest Doe & Sons in the 1950s and 1960s in
Ulting
Ulting is a small village and civil parish in the Maldon district, in the county of Essex, England. It shares its borders with Langford and Nounsley. It the location of Ulting Wick garden.
History
Ulting was the location of the first sugar ...
Essex
Essex ( ) is a Ceremonial counties of England, ceremonial county in the East of England, and one of the home counties. It is bordered by Cambridgeshire and Suffolk to the north, the North Sea to the east, Kent across the Thames Estuary to the ...
. Its two engines and 90-degree articulation made it one of the most unorthodox tractors ever built.
Development
During the 1950s farmers in the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...
in need of high-
power
Power may refer to:
Common meanings
* Power (physics), meaning "rate of doing work"
** Engine power, the power put out by an engine
** Electric power, a type of energy
* Power (social and political), the ability to influence people or events
Math ...
tractors had few options. Essex farmer George Pryor developed an ingenious solution to the problem by creating his own tractor. He did this by purchasing two
Fordson
Fordson was a brand name of tractors and trucks. It was used on a range of mass-produced general-purpose tractors manufactured by Henry Ford & Son Inc from 1917 to 1920, by Ford Motor Company (U.S.) and Ford Motor Company Ltd (U.K.) from 1920 ...
tractors, removing the front wheels and
axle
An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...
s and linking the two by means of a turntable which provided the steering action powered by
hydraulic rams
A hydraulic ram pump, ram pump, or hydram is a cyclic pump, cyclic water pump powered by hydropower. It takes in water at one "hydraulic head" (pressure) and flow rate, and outputs water at a higher hydraulic head and lower flow rate. The device ...
. This left him with a double-engined four-wheel—drive tractor capable of producing more power and outperforming any of the conventional tractors on the UK market at the time.
Commercial production
Local Fordson dealers Ernest Doe & Sons agreed to build an improved version, the first one was completed in 1958 and called the Doe Dual Power, later changed to Doe Dual Drive and abbreviated to Triple-D.

The first Doe Triple-D used two Fordson Power Major units producing , the later Triple-D 130 used two Ford 5000 tractors increasing the power output to over and the Triple-D 150 was based on Ford Force 5000 tractors producing .
The vast majority of Triple-Ds were sold in the UK, but a number were exported to the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
and elsewhere.
Disadvantages
The main disadvantage with the Triple-D was the lack of suitable implements for such a powerful tractor, this meant that Ernest Doe & Sons also had to develop and build a range of implements to sell with the tractors.
Other disadvantages stemmed from the use of two engines, this made controlling the tractor more difficult because of the need for two
gearbox
A transmission (also called a gearbox) is a mechanical device invented by Louis Renault (who founded Renault) which uses a gear set—two or more gears working together—to change the speed, direction of rotation, or torque multiplication/r ...
es. There were two engines and gearboxes to maintain and repair and the probability of breakdowns was increased.
End of production
By the late 1960s several companies had developed single-engined tractors capable of producing over , this competition and the need for Doe to develop and test a approved safety rollover cab put the Doe out of production after over 300 had been built.
Legacy
The Triple-D often makes appearances at agricultural fairs such as the Epworth Festival of the Plough in
Epworth, Lincolnshire
Epworth is a market town and civil parish on the Isle of Axholme, in the North Lincolnshire unitary authority of Lincolnshire, England.OS Explorer Map 280: Isle of Axholme, Scunthorpe and Gainsborough: (1:25,000) : The town lies on the A161 ro ...
and LeSueur, Minnesota Pioneer Power Days show where it is always a crowd favourite, popular due to its unorthodox build.
Triple-Ds are worth a great deal due to their relative rarity, even unrestored Does can demand extremely high prices at auction.
The Triple-D is also available in a 1:16 Scale model produced by Universal Hobbies
link to picture of a model
References
External links
{{Commons category-inline, Doe tractors
Ernest Doe homepage
YouTube footage of Does ploughing at Epworth
Tractors