Snatch straps and D-Shackles

[jzmq]

Does anybody use a d-shackle to connect there snatch strap to thier or another persons vehicle? I'm thinking of a situation where one of the vehicles does not have a tow hook, but instead have one of the closed recovery points that are seen on some of the newer cars these days. How would you suggest attaching a snatch strap safely to the car?

Since most d-shackles under an inch seem to be rated up to only about 15,000 lbs while the strap itself is usually rated between 25,000-30,000 lbs, it seems like the shackle may be the weak point.

Any comments, suggestions, etc...?

John

[Mark W]

The rating you are seeing on the shackle is the WLL (working Load limit). Breaking point is going to be 3 to 5 times the working limit. The rating on the strap is the actual tensile strength.


Mark...

[spressomon]

Originally Posted by Mark W

The rating you are seeing on the shackle is the WLL (working Load limit). Breaking point is going to be 3 to 5 times the working limit. The rating on the shackle is the actual tensile strength.


Mark...

D shackles are also WLL rated.

[spressomon]

Originally Posted by jzmq

Does anybody use a d-shackle to connect there snatch strap to thier or another persons vehicle? I'm thinking of a situation where one of the vehicles does not have a tow hook, but instead have one of the closed recovery points that are seen on some of the newer cars these days. How would you suggest attaching a snatch strap safely to the car?

Since most d-shackles under an inch seem to be rated up to only about 15,000 lbs while the strap itself is usually rated between 25,000-30,000 lbs, it seems like the shackle may be the weak point.

Any comments, suggestions, etc...?

John

You didn't mention if you are trying to pull this vehicle from the front or rear. Does it have a receiver style hitch? If so use the loop of the snatch strap so that the hitch pin secures it to the receiver. Otherwise you may, depending upon the nature of the pull, have to use high grade (think 3/8") chain/hooks around the frame points to which you would attach a D shackle then the snatch strap to the D shackle. The main thing here is to avoid anything sharp coming into contact with your snatch strap. Also beware the chain 'link' is not designed for kinetic style snatching...but rather 'pulling'. If you want a very good resource get Bill Burke's recovery DVD...

[woody]

for non-snatch situations, I carry a 18" short 3/8" chain, one end with a slip hook, the other with a grab hook. Great for wrapping around frames and cages for emergency situations when you need to roll a vehicle back over. Works great for most bumpers too when a gentle tug is all that's required and you dno't want to wreck your strap by wrapping that around the sharp bumper edges.

screw-type D clevis's are useable for snatching situations, but I personally wouldn't trust anything else. I usually carry 3-4 of these on the rig....one on the rear bumper, one on the front, and two in the recovery bag.

[Mark W]

I recommend not ever using chain in combination with a strap for a snatch type of recovery. Chain stretches more than most realize and stores a good bit of energy all by itself. It can also bind and twist if you are not careful rigging it and break at a much lower load level because of this. If you have it attached to a highly elastic snatch strap this can be a very very bad thing.

If you do have to use a chain (it's still better than running a strap over a sharp edge which is almost certain to cut it), make sure you pay attention to how you rig it and do not get it twisted.

Attaching the strap to the hitch pin in a receiver works. But only for a perfectly straight pull. If you are pulling at an angle there is a high chance of cutting the strap on the mouth of the receiver.


Mark...

[e9999]

and I would think that the typical 5/8" pin in the receiver is not that strong anyway, maybe 10K lbs?

[rusty_tlc]

Originally Posted by e9999

and I would think that the typical 5/8" pin in the receiver is not that strong anyway, maybe 10K lbs?

I use a 5/8" grade 8 bolt rather than a regular pin. I think I read about that here?

[Kofoed]

Originally Posted by jzmq

Does anybody use a d-shackle to connect there snatch strap to thier or another persons vehicle? I'm thinking of a situation where one of the vehicles does not have a tow hook, but instead have one of the closed recovery points that are seen on some of the newer cars these days. How would you suggest attaching a snatch strap safely to the car?

Since most d-shackles under an inch seem to be rated up to only about 15,000 lbs while the strap itself is usually rated between 25,000-30,000 lbs, it seems like the shackle may be the weak point.

Any comments, suggestions, etc...?

John

Commercial shackles have a factor of safety of actually 6. The load limit is right on the shackle, usually in tons.

The 4wd tow straps are not for lifting, and the factor of safety is much less. A one inch shackle would be the last thing that would fail for this application.

[BlueCruiser84]

couldnt you just put the strap through its own loop? or is that not advised?

Brian

[rusty_tlc]

Originally Posted by BlueCruiser84

couldnt you just put the strap through its own loop? or is that not advised?

Brian

1 - It would be a PITA to pull a strap through it's own eye, twice.
2 - The idea of the D is to protect the strap from getting cut on the sharp metal edge inside the closed style "recovery" points.

I'm thinking of a situation where one of the vehicles does not have a tow hook, but instead have one of the closed recovery points that are seen on some of the newer cars these days.

I think the "recovery" points on newer cars are actually just tie down's for transport.

[Mark W]

You have to be careful looping the strap back through itself. I do it all the time, but it is very easy to wind up with it pulled so tight that you can't get it loose. It's a good idea to put something inside the loop before using it. A chunk of wood (like a 2x2 scrap) or a twisted and knotted up tshirt or rag. This goves you something that you can work loose or cut away to get the slack you need to undo the loop.

If you do put the strap into the receiver or use a receiver mounted point to atach the strap, it's a good idea to use a 5/8 grade 8 bolt instead of your usual receiver pin. Who really knows what that will take. Double shear on a 5/8 grade eight is over 58,000 pounds IIRC.


Mark...

[Rich]

Learn how to tie a bowlline knot. Normally tied with rope, works with strap also. With a bowline you can tie a loop and the knot will not lock up, even after being used for towing.

[metalonmetal]

ah, memories of boy scouts...

[Beowulf]

"The bowline has been called the king of knots. It will never slip or jam if properly made and thus, is excellent for tying around a person in a rescue. Begin by forming an overhand loop in the standing part. Then take the free end up through the eye, around the standing part and back where it came from."

-B-

[e9999]

Originally Posted by Beowulf

"The bowline has been called the king of knots. It will never slip or jam if properly made and thus, is excellent for tying around a person in a rescue. Begin by formatting an overhand loop in the standing part. Then take the free end up through the eye, around the standing part and back where it came from."

-B-

yup, my favorite. Use it all the time.

was taught this by a sailor friend of mine. He in turn was taught to do this with one hand, while hanging on for dear life with the other on a lifeline thrown from a boat!

[canyoneer]

My stock '94 Cruiser has loops of 5/8" stock bolted to the frame front and rear. I'm sure these were used as tie-downs, but are they hefty enough for gentle recovery operations? If I replaced them with D-rings, I'd have to find brackets that fit the threaded holes in my frame -- I would think I'd want to anchor them with two bolts -- not just one. I'd be fine with hanging D-rings on them to accomodate tow straps if the steel loops themselves are strong enough.

[NMuzj100]

Originally Posted by rusty_tlc

I use a 5/8" grade 8 bolt rather than a regular pin. I think I read about that here?

This was just covered in a article in TT but I'm sure the idea has been around awhile.

[Beowulf]

Originally Posted by canyoneer

My stock '94 Cruiser has loops of 5/8" stock bolted to the frame front and rear. I'm sure these were used as tie-downs, but are they hefty enough for gentle recovery operations?

Inspect them carefully to make sure the bracket and loop are in good shape. Check the fasteners too. Attach a tow strap to them with a D-shackle. The factory recovery loops on your '94 are up to the task for recovery.

-B-

[canyoneer]

Thanks, BW. Good advice.

Back to the knots of our Boy Scout days: I happened to need a couple of bowlines today, and since we'd been talking about bowlines I took a close look at them. I think the reason that they're so useful and don't jam up is that the line passes through the knot cleanly on its way to loop around the post (or whatever) rather than immediately getting tangled up in the knot itself. Anyway, that's the best I can do in words, and what I'm talking about is evident if you look at the knot.

[Mark W]

Originally Posted by NMuzj100

This was just covered in a article in TT but I'm sure the idea has been around awhile.

I'm sure that I'm not the first to have thought about it, but it just brewed up in my head one day while I was putting together a receiver mount for a pintle hook. I tend to overbuild stuff like that and I realized that the pin had potential to be a major weak point.

Mark...

[canyoneer]

Where do you get a D-shackle that you can count on? Marine supply stores? Is there a rating on them (like six-line bolts) that I haven't noticed? Is galvanized OK?

[polarweasel]

The rating is cast right into the curve of the shackle: "WLL 3T" or whatever the working load limit is. They are rated for overhead lifting, so that limit is somewhere between 1/3 and 1/5 the breaking strength of the shackle -- large margins of safety are important when there are 6 tons hanging over your head from a crane...

So the limit is very conservative for recovery applications, but shackles are cheap -- buy the biggest ones that will fit! I like Rockstomper...he's local and has quality stuff.

[e9999]

good hardware store will have them.
OSH has a bunch.

[bigndn]

Originally Posted by e9999

yup, my favorite. Use it all the time.

was taught this by a sailor friend of mine. He in turn was taught to do this with one hand, while hanging on for dear life with the other on a lifeline thrown from a boat!

I'd bet not too many people know how to do this..............but I do.

[e9999]

Originally Posted by bigndn

I'd bet not too many people know how to do this..............but I do.

could you tell us the one handed thing, please, I don't remember that part...

[rusty_tlc]

Originally Posted by e9999

could you tell us the one handed thing, please, I don't remember that part...

It's the only way I know how to tie a bowline but it's hard to explain.
You are holding the standing part of the rope in your left hand and the rope around your waist. Grab the other end so the tip is between you thumb and fore finger with the robe crossing your palm. loop your right hand on top of the rope between your left arm and the rope then back up by your waist, the standing end is making a half hitch around your wrist and the loose end of the rope. Pass the loose end under the standing end from the right hand side, you do this by grabbing both parts then shifting you thumb and forefinger around the standing end. pull the loose end back through the half hitch. It's way easier to do than explain.

[Jake94]

Originally Posted by bigndn

I'd bet not too many people know how to do this..............but I do.

Me too. the 'ol man was a steevador in the SeaBee's and tought me this when I was knee high to a puddle duck.

'Nother trick he tought me, that I've use several times during vehicle recovery, is a bowline can be tied in chain, Holds fast and doesn't jam.