Short-term survival is often a battle to overcome nature and accomplish small feats — building a shelter, starting a fire, purifying water and obtaining enough food to stave off starvation. However, if you think back to studying the gradual development of societies in ancient history, you may recall that long-term survival is mainly about efficiency.
Instead of remaining nomadic hunter-gatherers to provide calories for the day, cultures began to grow crops next to their settlements. Rather than painstakingly retrieve buckets of water each morning, we built dams and aqueducts to bring the water closer to us. These advancements meant less time and energy spent on menial repetitive tasks, and more time and energy to develop other cool stuff — like metallurgy, literature, medicine, and art. If we were still spending 90% of our time scavenging for food in the wilderness, we never would have progressed as far as we have.
One major advancement in technology was the realization that flowing water could power machines. We call this technology hydraulics. Today's massive hydroelectric dams harness the energy, but it can also provide power for small primitive machines. In the following video, our favorite barefoot YouTube survivalist Primitive Technology builds a device known as a monjolo in Portuguese or karausu in Japanese. In English, it could be called a hydraulic hammer. This machine functions as an automated mortar and pestle, using flowing water to lift and drop a hammer head, pulverizing substances into a fine powder.
The main purpose of this tool is to produce flour from grain or other starches, like dried cassava. Once you have flour, it's possible to make simple bannock bread over a fire, or to get more creative and begin producing all sorts of delicious recipes. Toss some flour in with meat drippings and a little water, and you've got gravy. You get the idea.
Alternatively, the hydraulic hammer can be used to crush natural clay chunks into fine dust for pottery production, or to make activated charcoal powder for water filtration or medical treatment. The video description states, “A stone head might make it useful as a stamp mill for crushing ores to powder. It might pulp fibres for paper, even.” None of this requires hard manual labor — the water powers the monjolo hammer and does all the work. It's an ingenious device, and this Primitive Technology video does a great job of demonstrating the build. If you're feeling adventurous (and patient), get out there and try building your own!