Recovery gone wrong. Yes, rope can blast through a windshield!

freedom_in_4low said:
Don't know, winch manufacturers don't rate them by WLL, but should be generally safe to assume that a winch and mounting, if done per industry convention, would be solid up to its rated line pull. Everything else is easy though...i'd prefer my winch motor to stall before I exceed the capabilities of anything that can fly.
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If you don't know the WLL of the winch or whether it even has one, then you can't compare the WLL limit of any rigging with any degree of effectiveness whatsoever. That and you can't mix and match industries. The WLL limit minimum for overhead lifting is 1/5th of breaking. That means the typical 3/4" alloy bow shackle with a 7/8" pin with a 4.75 ton WLL breaks at over 45,000 lbs. and that's just stupid overkill. Add to that a few other things and your winch in a straight line pull can't even break a quality alloy 7/16" bow shackle.

If you apply WLL constraints to most 9500 lbs. rated winches, then the most you should pull is 1900 lbs. to stay within those standards. The other part of that is there is only a very narrow set of conditions whereby you can achieve the rated poundage in pulling power your winch is rated at. It has to be on the first drum layer, it has to be past the 5 wrap minimum they want on the drum, and all the slack has to be fully out of the line. Statistically, you'll never do that which also means you will almost never be able to use your winch at the capacity you paid for.
freedom_in_4low said:
Back on the kinetic rope though, I'm not suggesting anybody bring a slide rule to a recovery and do a bunch of math. I'm just saying that the industry could make it easier to compare and select the right rope as well as know a little about how to use it and what to expect, which right now they can only learn by watching YouTube or just finding out in what may be a dangerous situation.
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Look around, you do realize you are the only dog gnawing on this bone, right?
 
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mrblaine said:
If you don't know the WLL of the winch or whether it even has one, then you can't compare the WLL limit of any rigging with any degree of effectiveness whatsoever. That and you can't mix and match industries. The WLL limit minimum for overhead lifting is 1/5th of breaking. That means the typical 3/4" alloy bow shackle with a 7/8" pin with a 4.75 ton WLL breaks at over 45,000 lbs. and that's just stupid overkill. Add to that a few other things and your winch in a straight line pull can't even break a quality alloy 7/16" bow shackle.
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I'm aware.

mrblaine said:
If you apply WLL constraints to most 9500 lbs. rated winches, then the most you should pull is 1900 lbs. to stay within those standards. The other part of that is there is only a very narrow set of conditions whereby you can achieve the rated poundage in pulling power your winch is rated at. It has to be on the first drum layer, it has to be past the 5 wrap minimum they want on the drum, and all the slack has to be fully out of the line. Statistically, you'll never do that which also means you will almost never be able to use your winch at the capacity you paid for.
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also aware. And that's all making my point. Everything is rated way past what the winch will do and I'm not lifting anything overhead.


mrblaine said:
Look around, you do realize you are the only dog gnawing on this bone, right?
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I was just spitballing for conversation and you're the one that had to gnaw. The only reason WLL got pulled into this is because I threw it out arbitrarily as a semi-related measure people use to compare the products they're buying, and the products that are rated using that criteria are comparable using that criteria. I could have just as easily used rated line pull but it took more letters but you probably would have fixated on it all the same. All I'm saying is that there is no useful criteria that makes it easy to compare one kinetic strap to another and offered a possibility that could actually differentiate between two ropes that both had the same "strength" rating. It not a rope or a chain, it's an energy storage device and marketing them by their break strength is as useful as judging a suspension spring by how much tension will break the spring wire.
 
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mrblaine said:
I've been involved in several extrications where the only option was a kinetic rope. Bottom of a canyon, nothing but mud, no anchor points anywhere, my rig weighed the same as the Grand Cherokee buried to the bottom of the rockers all the way around. All the winch would do is get me muddy and drag my rig to them.

No one else was silly enough to ski down the muddy hill to where they were.

What should I have done?
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I do the same often enough. For mud and sand its my prefered method. Put tension on the kinetic rope and wait. When it gets slack do it again. If you take your time nothing needs to be violently jerked around or ripped off the rig
 
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freedom_in_4low said:
As it is, they give a breaking strength which is so meaningless they might as well not even publish it, because no one has any idea how much load they're applying in a kinetic situation.
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The best these companies can do is post the breaking strength and what vehicles it works for. There is no way they can predict the situation or the intelligence of the end user.
 
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Is it still a good idea to put a blanket over the rope/cable and raise the hood on the stuck vehicle to prevent it from coming thru the windshield?
 
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B1Toad said:
Is it still a good idea to put a blanket over the rope/cable and raise the hood on the stuck vehicle to prevent it from coming thru the windshield?
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While one would think that putting a "damper" on the line would be helpful the problem becomes can you accurately predict where your failure points are and whether you placement of said damper will indeed do its intended job. Raising the hood certainly can provide protection but almost always at the cost of visibility.
 
There is a YouTube video from a year or two ago showing that a broken rope slips right through a damper like the old table cloth yank trick. Dampers don't do anything. Never did anything.
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Blackjack said:
While one would think that putting a "damper" on the line would be helpful the problem becomes can you accurately predict where your failure points are and whether you placement of said damper will indeed do its intended job. Raising the hood certainly can provide protection but almost always at the cost of visibility.
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When you're tying knots in winch line you can
 
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The weight of a vehicle is not the important consideration when pulling it out. The rolling resistance, plowing resistance and suction are more of a factor. Ever see a guy pull a rail car. Very low rolling resistance with steel on steel vs rubber in sand/mud.
 
bucky said:
The weight of a vehicle is not the important consideration when pulling it out. The rolling resistance, plowing resistance and suction are more of a factor. Ever see a guy pull a rail car. Very low rolling resistance with steel on steel vs rubber in sand/mud.
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The stuck vehicle's weight is offset heavily (pun intended) by the factors you note above. However, the weight of the towing vehicle is certainly a big factor. Think of a TJ stuck in the mud getting pulled by a Suzuki Samurai, and then think of it being pulled by a freight train, both a low speeds. The Samurai will gently stretch the rope and stop. On the other hand, the freight train won't even slow down, and the rope will stretch to its limit and snap back. I think the towing vehicle's weight is the one @freedom_in_4low meant, since he was talking about the energy storage of the rope (mass and velocity), and the velocity of the stuck vehicle is zero at the beginning of the stretch.
 
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bucky said:
.... Ever see a guy pull a rail car. Very low rolling resistance with steel on steel vs rubber in sand/mud.
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As soon as the guy can overcome the inertia of an empty 30 ton rail car, he can pull it further than one might think.
 
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