Pape

the pic is right, the 9000 on the line indicate that there is still only 9000 lbs on that section of the line.

look like we are going in advance winching: keep in mind you need to be at 180º to gain the full power from the snatch block, at 90º you're closer to 1 1/2 the pulling power.
You can also use multiple snatch block to increase the pulling power or like one of the Aussie member on this forum use 5 snatch block and pull himself from behind with a front winch: man that must be hard on the frame

caprob

Don't listen to this idiot. The only way you can multiply the pulling force Is by returning the line back to yourself otherwise the block is just like a hard point. Trust me...I'm a ship captain with 42 years of sailing and yachting experience. A block is used to multiply your winch cap as described above or redirecting the force, ie. pulling someone else or pulling yourself in a direction other than linearly forward. If you have two blocks or even more, like I carry, you can get more creative but be careful because it's sometimes difficult to control pulling vectors

Fugg it

x2, the above picture is wrong. the snatch block or pulley is not a mechanical advantage, it is a change of direction. Regardless if it goes back to the jeep or not, your load is still the exact same. Imagine a snatch block hanging above you from a tree, your weight below it is still 200lbs whether it is attached to the snatch block above or thru the pulley and back down t you. Now if there was a pulley on you it went back thru, your talking about a mechanical advantage and less pull to lift u

Tripletsi

Actually after research the picture is correct, and so are you. It would be beneficial if it had a third drawing really. Your tree theory got me thinking, what if it were opposite? Say I was on a stage catwalk at a theater, lifting 200lbs up to me. If I used just a single rope it would be the heavy 200lbs. Now if I put a snatch block on the 200lbs and anchored the end of the rope to the catwalk I was standing on I now would only be lifting 100lbs while the catwalk supported the other 100lbs. The advantage now is that the block is moving. Whereas before it was not moving when it was hanging in the tree.

In the end I now see a snatch block as being beneficial only for either changing direction, or pulling out your stuck buddy (unless you really want to start another topic comparing spooled line vs. live line with winch loads). As long as the block is mobile, it'll create less load on the winch, but not "double" the power as most people think.

caprob

Sorry guys, both wrong again! Didn't you take BASIC physics? A winch line out to a pulley and back to yourself is "virtually" doubling the capacity of the winch. Add a second pulley back at your bumper and now you split the load "virtually" into thirds. (less of coarse resistance) and so on. Change the pulling vector and it helps to use a plotting sheet like we do with "rapid radar" plotting to convert relative vectors to true. With some creative thinking and enough equipment, you can pull yourself out of a ditch forward AND sideways avoiding damage to your rear fender/quarter panel.

jeepmojo

but I think I trust the guy who just posted . A ship captain should know ..( can you explain this for those of us who don't quite get it yet ?)
*
Where would you add the second pully back at your jeep and how ? trying to imagine where yould attach the second pully before final attachment?

andy1ism

Caprob is correct. When you are winching, your work is to get your vehicle from point a to point b(stuck to un stuck). No matter what you do or how crazy your snatch block set up is, the same amount of work will remain the same(point a to b). By running your line through a snatch block and back to you, you are just spreading the workload to different parts of your setup. With a double line setup, your winch is required to pull double the length of rope opposed to a single line setup. But with the law of conservation of energy, since your winch is doing more work by pulling double the line, somewhere in your setup the workload has to be less. That somewhere is your winches motor. Even though its pulling more line, it is pulling less weight, hence doubling the pull capacity of your winch. it's really just cutting the the pull requirement in half but doubling the pull distance. That was a mouthful for a first post. I hope I'm correct and made sense.

andy1ism

Also, if you are ever pulling at your winch capacity with a proper snatch block setup, then you are effing stuck my friend.

RoysRig

One of the things people fail to realize is that the more line you have out the fewer layers there are on the winch spindle. This provides more pulling power with fewer layers on the winch.

Mark Doiron

This is a very confusing thread to read. There are references to first and second diagrams, yet I only see one diagram with two different winching setups ...



And the above quote, "Don't listen to this idiot" (not that I'd use that kind of language, nothing wrong with being cordial while disagreeing or correcting) isn't clear as to who is the "idiot". The quote above implies that the line is not returned "back to yourself", yet when I look at the diagram it is, in fact, returned back to the Jeep. Well, okay, it's a lousy diagram, but that's how I read it. I sure don't see that lower-most shackle as attached to a rock!

Bottom line: The comments in this thread are going to confuse folks rather than teach. Since this forum is supposed to teach, I'd encourage folks to include quotes of what you disagree with. And, stay cordial. Nobody out here is perfect. Meanwhile, I have my own opinion of how this all works from my days taking college physics. Maybe I'll call my youngest son and confirm my understanding: He's an engineering physicist.