Snach Blocks

[JoeMeg]

Just for reference,check this out. One block only gives more rigging options,no mechanical advantage. Joe.
HowStuffWorks "How a Block and Tackle Works"

[racerone3]

a snatch block gives more power than a straight line pull because there is more line spooled out, therefore wrapping around a smaller drum. it's basically changing the gear ratio of the winch as explained here How Does a Snatch Block Work? | eHow.com

[Roger S]

Most of the time I hook the snatch block to the achor point, tree, etc. Then double the cable back to the vehicle. That doubles the pulling power of the winch. If the cable is then too short, I carry extra cabe to run from the block to the tree, etc.

Yeah, getting the spool smaller helps a lot, but at any given spool size, doubling the cable back to the vehicle doubles the pulling power, minus any friction losses. You're basically putting the winch in a gear twice as low.

I have a huge ramsey snatch block I've never used. Those harbor freight ones go on sale for a few dollars. The Tulsa Ramsey plant is a couple miles from me.

[Jeff t-boss]

If you take a 2800lb capacity whinch for example. You can pull 2800 lbs WITH ONLY 1 layer of cable on the drum. Add another layer to the drum and that weight drops to 2000 lbs. A third layer drops it to 1630 lbs. That is why you want to get most of your cable out to get maximun pulling weights. I forgot what the exact formula is, but in general, less cable on the drum is more pulling power delivered. (This is also effected by mired depth, grade resistance etc.) More in-depth info can be found on this site if you search the words recovery or winch.

[Roger S]

mired depth

Never heard that term before, but I sure understand it's definition

[Jeff t-boss]

mired depth

Never heard that term before, but I sure understand it's definition

Carries back to my Army days as a Recovery Specialist. (Tracked Vehicle) To add and stay on the topic; The basic difference between a snatch block and a basic pulley is that a snatch block can be opened up to run cable/rope through it for rigging. With a pulley, you have to run the end of a cable/rope between the shells and over the sheave (roller) to rig. This is commonly impossible with anything (cable/rope) that has any type of mating end on it.

[Roger S]

OK I learned something, Jeff. I have a real snatch block, a 16,000 lb Ramsey. Never used it. Thought I was going to deck out my nissan truck with winch and stuff, then bought an argo instead. The pully block w/ hook, I leave on my winch cable. I have an old Warn w/o a brake, so doubling the line with the pully block makes it act like it has a brake.

I went to track school in the Army (reserve) although my unit was a supply unit w/ only trucks and jeeps they thought I needed basic track mechanic class. The first day of class, they took us to the range and we drove everything the army had on tracks.. back in the early '70's. That was fun. Well, I didn't drive the tank retriever.. the m60 was fun. Our unit did have an all terrain fork lift it would tilt side to side.