Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
Re: Winching technique questions
I've been winching for 24 years and broken the cable more times than I can remember. Here are my observations on winching safety:
The biggest danger when winching is spring. A tight cable isn't inherently dangerous by itself because it has very little stored energy. When it breaks, the pieces will fall to the ground with very little snap-back.
BUT if there is something in the rigging that has stretched, or bent like a leaf spring, WATCH OUT!
The nylon recovery straps are a perfect example of what not to do. They are made to stretch like a rubber band, so you can get a good running start. They will stretch to 150% or more before they break. When they are stretched like that they have a tremendous amount of stored energy.
Look at the strap in the picture Leve posted. That's a slingshot, guys. If there is a hook or shackle or snatch block on the end of it, you can shoot it to the moon!
A similar danger can be caused by a tree. Hook a snatch block six feet up a six-inch hickory and you can bend the thing half way to the ground. If something breaks, the tree will snap back like catapult, and take all your hardware along with it. Even a Jeep frame will stretch and bend a little, and store a noticible amount of energy.
When you are making your hookup, look at every component involved. If it is a potential spring, take it out if possible. If it's not possible, minimize it.
1 Don't use a nylon strap. On construction sites and in factories they use web slings for lifting. I don't know what they're made of, polypropylene maybe, but they don't stretch very much. Get one and use it for your tree saver. I have several an ironworker buddy got me. They will stretch maybe 5% and then start to shred.
2 Shorten it as much as possible. Wrap it around the tree a few times. If it breaks it will absorb a lot of energy pulling the wraps around the trunk.
3 If possible, after you have wrapped it loosely around the tree, fasten the ends together with a shackle. Then put your cable hook over as many wraps as it will grab. That spreads the load over more tree surface, which causes less damage. It also reduces the strain on each wrap of the strap, which means less stretch, less liklihood of a break, and in the long run, less wear on the strap. Put the shackle on the back side of the tree - it's a potential missle.
4 Keep it as low as possible on the trunk. Lower is less likely to bend or uproot it.
5 Where possible, use a BIG tree. It won't bend or uproot.
6 Keep as much hardware out of the rigging as you can. Every piece of steel is a potential missle. Again, in Leve's post, on the end of that strap there probably is a hook. The strap by itself probably wouldn't have gone through the windshield.
That appliles to recovery straps, too. I prefer the ones with a loop on the end instead of a hook. Too often the hook will tear through, break or bend open. When it does, it becomes a deadly missle. The strap flying around can be pretty bad, but wind resistance will sap it's energy fairly quickly, and if it hits you it's like being whipped; painful but not usually deadly. A hook or shackle, on the other hand, can fly a long way, and do a lot of damage when it gets there.
I have seen pictures of a recovery attempt where the whole bumper ripped off the back of a full-size pickup. Think what that can do at the end of a slingshot!
I prefer to use trailer hitch balls. They usually are pretty well connected to the vehicle, and are easy to put the strap loop over. If they do break off or rip out of a bumper, my hope is that they will spin out of the loop instead of going for a ride with the strap; I've never had to find out, thank you very much. Of course, the whole hitch or bumper can tear off too. Like my ironworker buddy says, "Don't be there and it won't get on you."
My second choice is to put the strap over an axel and pull it through the eye. That's often impossible because the stranded vehicle is buried to the axel in mud, but you rock-crawlers might get away with it from time to time. Just try to avoid the brake lines.
I look carefully for alternatives before I use towing eyes or hooks because the quality of the weld and the integrity of the metal it's welded to are unknowns. If it rips loose you've got a dangerous missle.
And of course, the jacket or blanket on the strap or cable, putting the hood up, keeping spectators to the sides and well clear, are all givens.