The other day when I was posting about ropes, I mentioned using a block and tackle to gain an advantage when lifting heavy objects. A block and tackle is a system of two or more pulleys with a rope or cable threaded between them.
The pulleys are assembled together to form blocks (snatch blocks) and then blocks are paired so that one is fixed and one moves with the load. The rope is threaded, or reeved, through the pulleys to provide an increased mechanical advantage that increases the force applied to the rope making it easier for you to lift a heavy object.
Block and tackles were widely used before the advent of power tools and still are often seen around construction sites. In the past, they could be seen at the peak of every barn, where they were used for lifting bales of hay into the loft. A block and tackle hung from beneath a tripod was used for many things including pulling well pumps from their shafts. Large animals were hung with them to make it easier to dress and skin them. You can use them to pull loads up ramps, move rocks and many other things.
The increased mechanical advantage can help you move loads that one person would normally be unable to handle. The increased mechanical advantage of a block and tackle can be determined by how many times a rope passes through the pulley system. One pulley equals one advantage; two pulleys equal two, and so on. If you want to lift a 100-pound weight, a one-pulley system would still equal 100 pounds. A two-pulley system would require half the energy or fifty pounds and a three pulley would require a third the energy or a 33-pound lift on the pull rope.
There is no way that I can explain all the possible uses of block and tackle in a short post. There are literally hundreds of different uses. I strongly suggest that you obtain a good set of block and tackles for your storage. They are available with rope, chain and cables; it is my suggestion that you should have a good set of the rope ones. They are much more versatile than either cable or chain. The chains get twisted and are mainly used on the ones for lifting engine blocks. Cables are normally used on heavy equipment and cranes. It will pay you to stock extra rope that will fit the blocks that you purchase.
Block and tackles have a learning curve. Take the set that you get out and play with them, see what you can move.