It was supposed to conquer Europe for the Nazis, but ended up conquering the whole world.
Probably, each of us has seen an ordinary 20-liter jerrycan for fuel. But did you know that this practical invention was created even before the Second World War, in which it played an important role?
In the 1930s, it became increasingly clear in Europe that a new military conflict was coming, for which countries had to prepare properly. Germany is planning a new strategy to avoid a repeat of the horrors of trench warfare in the First World War. The emphasis is placed on armored vehicles and their rapid movement, which, however, represents a serious burden on logistics.
Heavy machinery needs to be regularly refueled, which is still a major supply challenge. And the tanks are easy to recognize and quite vulnerable. Therefore, around the middle of the 1930s, the Germans began to look for a new container (box, tube) for fuel that would be easy to transport, durable, as light as possible, easy to handle and easy to store. The triangular boxes used until then were not the most practical.
A number of companies participate in the bidding process with various proposals that are tested by the German authorities in terms of practicality, durability, etc. The result of the tests and various modifications was the 20-liter tin Wehrmacht-Einheitskanister of 1937, developed by Vincens Grünfogel – senior engineer for the German company Müller. Its box is thought out to the smallest detail, which is confirmed by the fact that it is practically still produced today without major modifications. It was even more accepted by all the Allies during the war.
Why the Wehrmacht-Einheitskanister such a special container? First, because of the shape itself, which makes it possible to store a large number of boxes next to each other and on top of each other. It is also possible to simply place the tube on the vehicle or in the cabin. However, the construction is also well thought out.
The box is made of two parts that must be welded. At the same time, the weld seam is below the level of the side walls, so it is not susceptible to damage in the event of an impact. The handle is also just brilliant, it actually consists of three handles. The idea – a soldier can easily carry two full cans (one in each hand) or four empty ones (two in each hand). And if the forces run out, two soldiers can comfortably carry one tube.
The three handles also make it easy to pass from hand to hand during transport/handling. At the same time, the army already has high requirements for ease of use. In addition, when the box is not overfilled, an air pocket remains, thanks to which it even floats.

The speed with which the container can be filled and emptied is also important to the military. Therefore, the Wehrmacht-Einheitskanister received a wide neck, which was additionally equipped with a thin tube in the upper part, providing air supply and thus pouring became smooth. In addition, the lid can be used for relatively precise pouring without the need to use a funnel.
Its well-thought-out lever closure allows opening/closing with one hand and without the need for tools. Thanks to the seal, nothing comes out of the box and it can be used repeatedly. The inside is covered with rubber, which makes it possible to transport drinking water and also prevents internal corrosion.
In 1939, during the preparations for the war, the army already had thousands of ready-made containers. Motorized parts that are equipped with them also get a rubber hose. This should make it possible to obtain fuel, for example from parked cars or other available sources.
This was especially true for British soldiers who came into contact with German tubes for the first time during the effort to defend Norway. However, the advantage of German boxes over British ones was fully demonstrated during hostilities in North Africa.
At the beginning of the war, the British used 2 imperial gallon (approximately 9.1 liters) and 4 imperial gallon (approximately 18 liters) metal containers to transport fuel. The smaller one is quite strong but expensive to manufacture. Therefore, the 4-gallon container is widely used, but it has a number of problems. It is fragile.
These containers are made of relatively thin tin alloy and have crimped or soldered joints. But it is these joints that often crack and leak during transportation, resulting in large fuel losses. This is particularly dangerous when driving on rough roads in North Africa, where shipping containers often lose much of their contents.
There is also the problem of transporting a large number of these containers. If wooden crates are not used, but stacked directly on top of each other, the boxes on top can damage those below. The Allies thus lost a huge amount of fuel, but leaks in the cars could also lead to fires and caused the explosion of at least one transport ship. There is also the problem of fuel expanding in the extreme African heat, again leading to box failure and leakage.
Also, the tube only has one small handle, which complicates transportation and requires the use of a pouring funnel. In addition – the fragile construction means that the box is not suitable for repeated use. Thus, the British quickly appreciated the advantage of German boxes and began to use them on a large scale.

In the later years of the war, the Allies finally began their own production, which was greatly facilitated by the fact that they also received technical specifications for the German containers. The importance of the German boxes was also commented on by the American President Franklin Roosevelt, according to whom it would have been impossible to break through France at lightning speed without these containers.
During the war, the design of the German boxes was also copied by the Russians, who later adopted it as their standard. The German-British Jerrycan also became a standard for the armies of the NATO countries.
In 1970, Finnish designer Eero Rislakki designed the plastic Jerrycan, which is lighter than the original and still strong enough. Subsequently, the tuba was adopted by the Finnish army and made available to the public. Today, large, 20 liter tin cans are still used, but lighter and more compact plastic ones with a smaller volume are more practical.