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Weight rating and safety margins for yank straps...BIG WEIGHTS

AJMBLAZER

AJMBLAZER

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Question for work. I work with actual Army trucks, but am not in the Army and only distantly connected with the Army supply chain. We have no yank or tow straps and occasionally we get a HEMTT, MTV, or PLS stuck. Currently using chains that make me cringe. Not what I'd hook up to a 40-60,000lb vehicle.

The Army uses yank ropes for this...we don't have any and trying to order some through the military supply would take FOR-EV-ER since we're FAR down on the chain. Looking to get our own since it'd be safer and faster.

Somewhere I was given a theoretical weight rating of a 71,000 lb strap but I'm not sure where that came from. Our heaviest truck weighs 62,000lbs so I don't feel comfortable with only an extra 9000lbs there.
What's the general feeling in this area? 1.5x like winches? 71k enough? Tractor beams? Blow it in place?
 
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Well I believe the rule of thumb is that each inch of width is 10,000lbs on a good quality yank strap. My 3inchers are rated at 30,000lbs so I would think youd want a 10in wide strap for safety.

A 9000lb safety margin isnt enough IMO. I like to be safe IE I run my winch with a snatch block even when I dont need it, 30,000lb straps for 6000lb trucks etc.

Take a look at some crane or tug boat supply books. I know the straps and rope they use to pull container ships will do the job really really well.
 
Tow ropes, the steel cable ones only operators use. Whenever we went out on a mission with our HEMETT wrecker, we always, always use chains, unless we know we gotta winch it because of the ground, or angle, or it's really stuck or whatever. But just pulling real quick, chains all the way.

I've only broken a chain a few times, the last time I recall a Stryker was about halfway deep in the mud. Only used a chain because as we were pulling our big winch down, it snagged one of the hydraulic lines and cut it. Needless to say our other wrecker had to come out and grab it with thier 60k and snatch block. Fun times. :D

I dunno what cha do as a civillian, depot level maintainence? Thinking of purchasing your own, especially for work... yuck, those trucks can't be stuck enough where a little yank with a chain should scare you. IMO the best thing we use for vehicle recovery are chains, well of course the winch when needed.
 
sweetk30 said:
:whistle:

http://coloradok5.com/forums/showthread.php?t=252074

:thumb:
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Talking with ken already about some yank ropes.
mrschaeferpants said:
Tow ropes, the steel cable ones only operators use. Whenever we went out on a mission with our HEMETT wrecker, we always, always use chains, unless we know we gotta winch it because of the ground, or angle, or it's really stuck or whatever. But just pulling real quick, chains all the way.

I've only broken a chain a few times, the last time I recall a Stryker was about halfway deep in the mud. Only used a chain because as we were pulling our big winch down, it snagged one of the hydraulic lines and cut it. Needless to say our other wrecker had to come out and grab it with thier 60k and snatch block. Fun times. :D

I dunno what cha do as a civillian, depot level maintainence? Thinking of purchasing your own, especially for work... yuck, those trucks can't be stuck enough where a little yank with a chain should scare you. IMO the best thing we use for vehicle recovery are chains, well of course the winch when needed.
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We do the final outfitting, checking over, and distribution to the military end users. We receive them in as produced form from Oshkosh and do to them what and send them to where TACOM says. All civilian, which is part of the problem. None of my drivers are experienced with the trucks and certainly not M984 wrecker operators. Our equipment isn't the military approved stuff. The chains they have in the crew trucks definitely aren't what I'd want to haul a HEMTT mired to the hubs out of the Kentucky clay with.

I will say when I asked our QA/QAR guys what the Army recommended they came up with some 71k straps. Still not certain how or where they came up with that recommendation but it was along our train of thought.
 
I'm still not sure if 74k is enough to yank a 55k truck out of the mud though...that's not even 1.5 times...or our heaviest truck.

Waiting to hear back from Ken. He can do up to 600,000lbs in rope so I figure he'll have enough.

I was asked about the straps/ropes today in a meeting and it was funny trying to explain the issue to a bunch of folks who had NO clue what I was talking about.
 
just tell them you cant pull out a stuck object with a cheep hardware store rope.

its got to be done right. do it half a$$ and someone will get hurt or XXXX:doah:
 
Yeah.

I had a 30k strap that I mainly used when I got my POS work truck S10 Blazer stuck. Then we used it to get a HEMTT free that had gotten stuck on flat but soggy ground after the front diff lines froze. We had it looped between the two about three times.

Later we had one get very stuck crossing a crevice. We looped it four times and it popped the stitching like a zipper as we got the truck out. Worked though.
 
Before 9/11 I was a site supervisor for a crane rental company, not huge equipment but big enough, 400 metric tons lifting capacity, two hours later they were folded up and trucking back to the shop or to the next jobsite. Something sticks in my memory about a 4:1 ratio for unsticking big boy toys. Our largest OTR crane had 28 (including 7 axles for the boom) axles and had to be permitted to go across the street. That dude came from Leiberr with a tow strap that was 3/4" thick by 2 feet wide and maybe 40' long. If I can remember I think it tipped the weight scales a just under a mil (1,000,000 yea a one with 6 zeros!) Those things got stuck anytime it rained for more then an hour. When it was originally delivered to us it came in, in pieces on 14 flatbed trailers, when it was all put together there is the lifting rig and two oiler rigs (oilers pull counter weights, flying jibs, blocks, spreader beams, etc)

Just food for thought, if memory serves me I think the tow strap itself was around $10,000 for a replacement!
edit: just remember this is almost 10 years ago, so I would hate to think what that dude costs now!
 
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You're most economical deal here might be to just buy a spool of UHMWPE rope (commonly known as winch rope) and cut/splice it yourself. It was originally used for marine applications, and I have seen it sold in up to 3" diameter for tug boats. The yield strength on that (stress required to permanently deform i.e. "damage") was over 1 million lbs.

I have usually seen the "work rating" used as about 1/4 of the tensile strength (failure) on tie downs and recovery straps. There doesn't appear to really be a spec for these things though at least in the major public industry. It kind of sucks because nobody advertises yield and tensile strength like they should (except I have seen PE rope sold this way), which is really the only way for a guy to determine exactly what he needs. You'd need to choose something with a high enough yield strength and area that it gives you enough margin for the impulse without deforming the material permanently.

PE rope is the most practical material out there or this kind of stuff in my opinion. My wheeling buddies and I carry around 100' of extra rope on top of what's on our winches. It is very UV stable and chemical resistant (it's what gas cans and gas tanks are made out of), and when I bought it, it was more affordable per foot than trying to use flat straps or something, considering we wanted such long sections. It's also really light weight and doesn't take up as much space as a 4" flat strap.
 
To the hubs would be mire lvl 1, equal to the weight of the vehicle and cargo. So pulling a 62k truck would in theory be 124k. Them thAr be some heavy recovery straps. If I was still in I'd snag you a set :) I should go see if any of my buddies at the shop could 'aquire' any. Dunno what shipping would be on 60lbs of chain though. :D Or one of those straps.
 
This is kind of at a stop right now. The experts came back with a rating similar to mrschaeferpants's 124k. That makes for a VERY expensive rope that I'm frankly not sure I'd ever get permission to have bought.

So mrshaeferpants, does the Army even use a strap/rope for this or is it all chain/cable/tow bars? We're handicapped because we don't operate the recovery equipment on the wreckers. Basically looking for something simple, easy, redneck proof, and safe to use.
 
Whatever happened here?

In the sizes you are talking about, my ropes cant be beat. The ease of using them would be such a benefit.

Thats why the agricultural industry LOVES these ropes. Out in fields, soaked in mud... no one wants to pull a chain or cable that is big enough to pull out a 8 wheeled tractor stuck up to the hubs in mud. One guy can easily pull one of my ropes that is big enough.
 
We ended up getting a towbar setup through .gov. Recovery and vehicle moving setup now.
 
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