Synthetic rope failure: Does it drop or recoil?
- Thread starter jjvw
- Start date
We are coming at this from two different areas of expertise. Yours is from an actual winching and practical side while mine was intended to provide some awareness and safety issues for those without them. The above videos show just how dangerous steel cable can be. Anyone can go out, buy and install a winch and not be aware of some of the inherent dangers. I don't want to see or hear of anyone losing an eye, a limb or worse from not being aware of the dangers in using a winch.
My entire reasoning behind ever posting in recovery or winching discussions is to keep folks safe and make them aware of the dangers. That is done through education and we need to keep everything in the correct context. The biggest single area of information that confuses the crap out of folks is mixing industries and the rules thereof. You can NOT put forth the rules of overhead lifting and safe WLL relative to breaking strength unless the rest of the devices in use adhere to the same rules. That includes the winch itself starting with what the definition of a winch is and why it is not a hoist. If you want to apply the rules of WLL used in overhead lifting, then the average 9000 lb rated winch will only be allowed to pull at 1/5 of that rated capacity. Since we don't and can't do that, the rest must also be irrelevant.
The above should be studied, memorized, studied some more and then used to understand why some of us continually rail against all the mythological bullshit surrounding recoveries.
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this is correct because there is a 5:1 safety factor for hoisting where winching there is not. if the same rules applied, the winch would need to be rated at #45,000, I dont know if my bumper could handle that much winch.
You make a valid point about mixing industries, the rules and confusion to the novice. I can't help but to defer back to my training and experience in heavy loads and critical lifts; it's just ingrained. The safety aspects regarding any type of winching are universal as shown in the video. Never place yourself in the line of fire. QUOTE="mrblaine, post: 381303, member: 164"]
My entire reasoning behind ever posting in recovery or winching discussions is to keep folks safe and make them aware of the dangers. That is done through education and we need to keep everything in the correct context. The biggest single area of information that confuses the crap out of folks is mixing industries and the rules thereof. You can NOT put forth the rules of overhead lifting and safe WLL relative to breaking strength unless the rest of the devices in use adhere to the same rules. That includes the winch itself starting with what the definition of winch is and why it is not a hoist. If you want to apply the rules of WLL used in overhead lifting, then the average 9000 lb rated winch will only be allowed to pull at 1/5 of that rated capacity. Since we don't and can't do that, the rest must also be irrelevant.
The above should be studied, memorized, studied some more and then used to understand why some of us continually rail against all the mythological bullshit surrounding recoveries.
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It's all good my man.
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Here's some anecdotal evidence that a synthetic winch line can snap back with some speed if it breaks under load.
On the other hand, it doesn't always happen like that.
On the other hand, it doesn't always happen like that.
OP
The Jeep was buried to the axles and resting on the center skid in heavy wet snow. The tree I selected as an anchor would have pulled me back onto to the existing trail and was about 75-80 feet away. I have (had) about 92 feet on the drum. While this created the side load, I was making an attempt to "stay the trail". The pull occurred on the first wrap with about 2/3 of the drum wrapped. No more than 3/4.
The rope parted at the steel hawse after the thick powder coat wore away, revealing the rough steel surface below. Less than 6" frayed where it dragged against the hawse before the snap.
Here is the recoiled rope gathered at the tree with the Jeep in the distance. Everything else inside the hawse is on the drum.
The closer anchor tree was a straighter pull, but took me off trail. I ended up tying the rope ends together, winding in several wraps and pulled myself free. I didn't do a splice because it didn't specifically matter in this immediate instance where I didn't need the length.
Judging by the sound of the winch, I suspect the loads were similar. Meaning the load that snapped the first pull with no movement was similar to the one that got me free. These pulls were slower than others where I would be skating on a rock face. Granted, there is a lot of conjecture and assumption with this observation.
Ultimately, as I understand what happened, the steel hawse fairlead is what caused the failure. And synthetic winch rope does not just fall to the ground.
The rope parted at the steel hawse after the thick powder coat wore away, revealing the rough steel surface below. Less than 6" frayed where it dragged against the hawse before the snap.
Here is the recoiled rope gathered at the tree with the Jeep in the distance. Everything else inside the hawse is on the drum.
The closer anchor tree was a straighter pull, but took me off trail. I ended up tying the rope ends together, winding in several wraps and pulled myself free. I didn't do a splice because it didn't specifically matter in this immediate instance where I didn't need the length.
Judging by the sound of the winch, I suspect the loads were similar. Meaning the load that snapped the first pull with no movement was similar to the one that got me free. These pulls were slower than others where I would be skating on a rock face. Granted, there is a lot of conjecture and assumption with this observation.
Ultimately, as I understand what happened, the steel hawse fairlead is what caused the failure. And synthetic winch rope does not just fall to the ground.
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OP
You went the wrong way sort of, you would back down the winch load to 2000 lbs or so. No one wants to lug around steel cable rated at 45K breaking.
Head Lice
TJ Addict
Was the deck hand on my buddy's 32' beach-comb tug. He had about 90' of tow rope out, and we were going to pull a grounded log boom off of the beach. Tow rope is 2" thick with a 10lb. steel hook.
Tow ropes have a real elasticity to them. The hook straightened out, and that whole mess came back onto the deck. The hook went through the door into the cabin. Skipper and I were unhurt. He didn't get touched, I just got hit with the rope. The hook would have gone through a person.
Tow ropes have a real elasticity to them. The hook straightened out, and that whole mess came back onto the deck. The hook went through the door into the cabin. Skipper and I were unhurt. He didn't get touched, I just got hit with the rope. The hook would have gone through a person.
It's all good my man.
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I get that. I also get that every rigging hand, crane hand etc. that works around overhead lifting does the same thing while at the same time violating the same things ingrained through their training every time they use their winch. It has to be consistent, relevant, and easy for everyone to understand. Few in general understand that the standard 3/4" bow shackle with a 4.75 ton WLL (9500 lbs.) breaks at nearly 50,000 lbs. of load and their winch is incapable of breaking a 7/16" version with a 2 ton WLL. 9500 was picked and declared the standard using the rules of an industry that simply don't apply.
The problem with the second video is they arrived at the wrong conclusion. There are two reasons that the recoil was low, the first is the impact load from the rig rolling back stressed the rope against the fairlead and that allowed a failure with little stretch in the rope.
Synthetic rope itself should just fall in theory if it has zero stretch. Or at least all but just fall with far less than lethal recoil force. Are you convinced the recoil wasn't due to some stretch in your tree strap or even deflection and recoil of your anchor tree?
I get that. I also get that every rigging hand, crane hand etc. that works around overhead lifting does the same thing while at the same time violating the same things ingrained through their training every time they use their winch. It has to be consistent, relevant, and easy for everyone to understand. Few in general understand that the standard 3/4" bow shackle with a 4.75 ton WLL (9500 lbs.) breaks at nearly 50,000 lbs. of load and their winch is incapable of breaking a 7/16" version with a 2 ton WLL. 9500 was picked and declared the standard using the rules of an industry that simply don't apply.
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To be honest with you I don't use a winch for some of the very reasons you stated. I carry a bag with shackles, synthetic slings, assorted rigging hardware, a 3/4 ton come along or a 1 ton chain hoist if I think I'll need it. It is a more cumbersome way of doing things but it gives me total control and flexibility. I have only had to use this combo. twice but it works and I remain well within safety practices and load ratings. 35 years working in a very demanding industry with high standards will do this to a person. As I've mentioned, I cringe when I see some of the videos with people using a winch. Many are clueless.
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OP
The tree strap is nylon and has some stretch. About 10% depending on what you read. I'm not convinced that our winch ropes don't stretch. 1% of 80 feet is still about 10". Then add in everything else in that system.
One reason I use synthetic and have been changing my rigging to lighter materials is exactly because of what happened yesterday. If something fails, I want to minimize the fallout. The largest failure in my setup yesterday was the hawse.
Incidentally, I ordered a TRE aluminum hawse from 4LowParts last night. When I can address the rope, chances are that I will just get rid of the short section on the drum. Maybe I'll splice it into a short extension with an eye on either end.
One reason I use synthetic and have been changing my rigging to lighter materials is exactly because of what happened yesterday. If something fails, I want to minimize the fallout. The largest failure in my setup yesterday was the hawse.
Incidentally, I ordered a TRE aluminum hawse from 4LowParts last night. When I can address the rope, chances are that I will just get rid of the short section on the drum. Maybe I'll splice it into a short extension with an eye on either end.
That was my point If the same safety factors applied we would have massive winches to do this work
All the synthetics for winch use have listed elongation factors at different loads.
Did you watch the video and pay attention to the parts with line weights tossed over the lines under load?
Most winch users are clueless and have no idea what can happen. You can readily tell that by some of the products they purchase and hang from their rigs. It is only luck and the seldom use of those items that someone hasn't had their head taken off.
If you wheeled in our area, you wouldn't use the chain hoist or come along more than once. It would then be relegated to an area for it intended purposes and you would wind up with a winch of some sort on the front.
OP
I'll watch tonight when I get home. And I want to try to find the elongation factor on my rope.
Most of my off roading consists of gravel trails, state forest trails, fields, etc.. If I did more hard core off roading I would look into the right winch to handle the situation and agree with you that most have no idea just how quickly things can go south using a winch. I believe they provide a false sense of security that can get the inexperienced into trouble.