Block and Tackle Pully System - How do I use it?

After doing some searching on the gear forum, I have not found much discussion about block and tackle pulley systems.


I have acquired a an older set that the owner utilized for lifting and hanging deer after hunting season and the ropes look pretty rough. I'm planning on 'restoring' the set but outside of what the past owner has used it for, I'm not sure what I'd use if for.

What/how do you folks utilize this kind of gear. Is there a modern alternative that you utilize?

Basically, the amount of force applied by a pulley(s) is multiplied by the number of times the pulling cable is added.  With a single pulley attached to the ceiling, and one length of the rope supporting the load, a pulling force of 50lbs results in a pulling force of 50lbs on the load.

If you add a second pulley wheel (one on the ceiling, and one at the load), you double the force.  50lbs of force on the rope yields 100lbs of force on the load.  But, the amount of rope you have to pull doubles.  So, in the first example, if you pull 1 foot of rope on the ceiling pulley, you lift the load 1 foot off the ground.  With the second example, you need to pull 2 feet on the rope to lift the load 1 foot.

With three pulleys, you increase the force 3 times, but have to pull the rope three times as far, and with four pulleys, it's 4X the force, but four times the length of rope pulled.

In each case there is conservation of energy,  With four pulleys, it's 4X the force, but you have to pull 4X as long.

Does that make sense?  You could use pulleys for any heavy load you can't pull on your own.  Maybe a engine out of a car, lifting bales of hay to the second floor of your barn, or using pulleys to tighten fencing wire? Lots of applications.

Further to Michael; each pulley on the moving load increases force.  Pulleys on stationary anchors or motive force redirect motion.
And with a cunning arrangement of pulleys, UHMW rope and large logs you can pull the rear end off a Honda CRV.
Explain that one to your partner...