Let's examine the fuel figure in more detail. When we arrived at the three day trip duration, the chart was pulled out and a rough activity plan drawn up. 660 L Since our fuel tank holds 270L, we needed a further 390L of fuel onboard. Then we discovered the 60L drum. These drums originally contain automotive finish thinners.
Most panel beaters have a few empties Iying around.
However you have to be careful to ensure they aren't rusty or contain water. Contaminated fuel is the last thing you need on a long trip. We worked out seven of these tanks would do the job with some 30L to spare. That sounded a pretty good safety margin at first, but in reality its a pretty thin margin for such a long run. However our schedule was fairly flexible, and if need be, we could always reduce the travelling distance of our fishing forays if the fuel started to get too low.