Cultivator No. 6 – An Insane Trench-Digging Machine
The Cultivator No. 6 was a mad, eccentric and undeniably British trench-digging machine invented in the early months of WWII. It went by many names, such as the N.L.E. Tractor, the mole, Nellie and White Rabbit Number Six.
It was the brainchild of Winston Churchill designed to break the stalemate of trench warfare.
It was one of the largest and heaviest moving military vehicles at the time, yet it never entered service. Many had already thought the idea was a waste of time, and, as WWII soon proved, they were right.
“I am responsible but impenitent”Winston Churchill
The horrors of WWI’s trench-warfare had left a long lasting scar on all of those that had been involved in the fighting. Many expected – or more accurately, feared – that the next major war would devolve into similar conditions.
With WWII looming, countries in Europe still traumatised by WWI prepared themselves by creating machines and strategies that would prevent such an eventuality.
In the early days of WWII Winston Churchill was made First Lord of the Admiralty, a position he had held before during the Great War.
Churchill was known for his excellent ability to clearly envisage a problem solving idea and make that idea a reality. He used this to great effect in WWI, where he was imperative in the creation of the tank.
However, less known is his idea for an armored trench digging vehicle that could dig straight through No Man’s Land. He imagined that troops and vehicles could follow the machine through the freshly made trench, protected from enemy fire.
This was the basic idea behind the Cultivator No. 6.
The idea never caught on in WWI, but in the opening weeks of WWII Churchill brought it back up.
As First Lord of the Admiralty he had significant influence and could get the project moving. He gave the task of investigating and building the machine to J.H. Hopkins, a highly skilled ship designer.
The top secret Department of Naval Land Equipment was established under the Ministry of Supply to oversee these sorts of projects. This department was abbreviated to NLE – something that will crop up again later.
After exploring a number of different designs the team eventually produced a working scale model that Churchill showed to the British government.
After these displays the government gave the go ahead for the production of 240 trench digging machines.
Designers had figured that the machine would need around 1,000 hp; split roughly in half between moving and digging. Initially they had planned to use the relatively new Rolls-Royce Merlin engine, but the RAF had been given almost complete priority for these engines.
Sir Harry Ricardo suggested using two of 600 hp Paxman diesel engines instead. This actually ended up as a better system, as the digging and automotive systems could have their own dedicated powerplant.
Cultivator No. 6
The resulting machine was a sight to behold. It went by a number of names, all of which disguised its true purpose These were White Rabbit Number Six, Cultivator No. 6, N.L.E Tractors, and Nellie, in reference to the NLE department.
Also, Churchill was known to often refer to the machine as his mole.
The Cultivator No. 6 had two main parts; the head and the body. The head was responsible for actually digging the trench, while the body provided the machine’s movement.
The head was a large machine in and of itself, weighing around 30 tons and measuring 9.3 m (30 ft 6 in) long, 2.6 m (8 ft 7 in) high and 2.2 m (7 ft 3 in) wide. It connected to the body via a hinge, allowing it to pivot up and down to ascend or descend.
A large plough blade cut through the upper 2 ft 6 in of soil, while a rotating cutting cylinder removed the lower 2 ft in of soil.
The body of the machine was over 14 meters long and closely resembled a WWI era tank. This section weighed 100 tons. Its 2 ft wide tracks ran around the entire outside of the vehicle, which had a top seed of 3.04 mph on the surface.
Fully assembled, the monstrous Cultivator No. 6 was 23.62 m (77 ft 6 in) long and weighed 130 tons.
Lean, Mean Digging Machine
Despite its heft and rather cumbersome appearance, the Cultivator No. 6 was very good at accomplishing its design requirements: cutting a trench through soil.
At full speed the machine could dig around 0.5 miles of trench in an hour, moving 8,000 tons of soil in the process.
As it went it would cut a trench 1.5 m (5 ft) deep and 2.3 m (7 ft 6 in) wide. The soil removed from the cut was then deposited along sides of the trench by conveyors on top of the machine. This added another few feet of depth to the trench.
In action the Cultivator No. 6 would begin cutting a trench from friendly lines, digging through No Man’s Land towards the enemy’s lines.
To prevent the operation from being seen and heard it would have been carried out at night during an artillery barrage. Troops could follow the machine through the trench to the enemy position, where the Cultivator No. 6 would then be used as an exit ramp for men and vehicles.
Though the machine showed promise, it would never seen action. From the earliest stages of the war it was clear combat had changed dramatically since WWI. It was not going to be fought in trenches, and as a result, Cultivator No. 6 had no use.
Trials for Churchill’s mole continued until early 1942 though and the project wouldn’t be cancelled until May 1943.
Five are believed to have been built, including the pilot vehicle. However four of these were scrapped soon after war, with the fifth surviving until the 1950s, when it too was scrapped.
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Today there is nothing left of these remarkable machines except photos, and as such they remain a relatively unknown piece of engineering.