Beginning physics taught every pulley reduces the force to move an object by 1/2.
The oldest tool I own is an 1800's Cast Iron Wire Fence Stretcher Rope Double Pulley system. The fence jaws have been recently replaced but the rope and pulley system still works for stretching barbwire fence. It was my father's and I suspect grandfather pick it up at a farm sale. The pulley system is rated for 250 lbs pull and works great.
In 2021, I purchased 2 climbing rope pulleys. Asplundh tree service came and cut down 3 larger aspen trees from under the power lines running in front of the property. Two fell cleanly into an opening but the last one landed on brush and small trees. It was hung up 12 to 15 feet in the air. Naturally they left before I discovered.
I started to cut the tree out of the brush but needed a way to pull cut branches out of the tangle of brush. I purchased 2 climbing pulleys for Northwest Sports.
The pulleys were designed for 1/2" climbing rope but did not allow for 3/4". They worked on all but the largest branches. Gave up pulling the trunk out of brush pile. It was just too heavy for the rope and pulley system.