How to carry a jerrycan
The German army wanted their Blitzkrieg to maintain momentum and so they required each soldier to hustle with four empty jerrycans – two in each hand. The solution was the triple handle: one handle on the left, one in the middle and one on the right.
When the can is filled with fuel, you use the middle handle to carry it; when it’s empty, you use the right handle and grab a second empty can by its left handle with the same hand.
If a German tank driver had to walk several kilometres from a fuel depot to where his Truppenluftschützenpanzerwagen stood without fuel, he could ask a comrade to help him. Then they would share the 20 kg burden by each holding on to an outer handle.