Of all Hitler’s WW2 ‘secret weapons’, one has survived unchanged to this day and remains in use by most armies of the world and millions of civilians. It may seem odd that something as innocuous as a canister for storing petrol would be designed and introduced under conditions of utmost secrecy, but that is exactly the circumstances in which the Wehrmachtskanister entered the world.
Hitler and his generals, secretly planning a fast-moving Blitzkreig across Europe, realised that even the best tanks in the world are pretty useless without a constant supply of fuel to feed them. As the British were to find out to their bitter cost in the North African campaign, petrol containers of the day were simply not up to the rigours of modern mobile warfare.
With typical thoroughness, German engineers set about designing the über-can. The design brief was pretty straightforward: make it strong, easy to open, easy to pour and easy to handle. The result was a minor masterpiece of ergonomics.
The 20-litre capacity canister was formed from two pressed-steel shells seam-welded together. Indentations in the sides added strength and also allowed for expansion of the fuel. So far, fairly straightforward, but the clever bit was at the top. The top deck was chamfered at the spout end to allow easy pouring and curved upwards at the rear to create a domed cavity. This meant that the can could not be fully filled and the resulting air space allowed for expansion of the fuel and provided buoyancy if the can was dropped into water.
While three parallel handles might seem like two too many, they were designed to allow the easy passage of cans from man to man in a ‘bucket-chain’ operation. The neck doubled as a spout, obviating the need for a separate funnel, and used a quick-release lever with a sealed lid instead of a screw top. A tube from the mouth to the internal air pocket allowed air in as fuel flowed out.
The final innovation was a lining of impervious plastic newly developed for the beer industry. In theory this meant that the cans could be used for both fuel and water.
In 1939 the German army had secretly stockpiled thousands of their new containers at Berlin’s Tempelhof airport, when a weird chain of events let the can out of the bag. Paul Pleiss, an American engineer living in Germany, was planning an overland trip to India, together with a German colleague, and they were casting around for a convenient and space-efficient way to carry a water supply. The German had access to the Tempelhof stockpile and ‘borrowed’ three of the cans, which they fitted under their vehicle. Before reaching India the German was recalled but Pleiss made it to Calcutta, where he stored the car, before flying back to the USA.
Pleiss tried, without success, to interest the American military in the new fuel canister. Eventually he shipped his can-equipped car back to the US and sent one to the Government which produced, half-heartedly, an inferior version with a rolled seam and screw cap.
Meanwhile, the Brits, fighting Rommel in North Africa, quickly concluded that their five-gallon petrol tins were hopeless. Rough handling easily damaged them and just standing still they sprang leaks as the hot sun expanded the contents and burst the seams, creating massive wastage. The ebb and flow of the desert war meant that German fuel dumps were frequently overrun and the British lost no time in adopting, and naming, the ‘Jerry’ can as their preferred container, and soon put an exact copy into production.
By D-Day, in 1944, millions had been produced, and by the end of the war it is estimated that around 21 million Allied Jerrycans were stockpiled in Europe.
The US, too, soon adopted the Jerrycan, which became an essential accessory on the back of another WW2 icon – the Jeep.