Sorry, my memory what what a normal 3/4" shackle is rated at was off by a ton. The Crosby alloy shackles are only 1.47 times as strong as normal 3/4" shackles at 7 tons.
https://www.uscargocontrol.com/Crosby-Anchor-Shackle-Screw-Pin-3-4-G-209A-7-Ton
School me on safe recovery and rigging
- Thread starter Tob
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Sorry, my memory what what a normal 3/4" shackle is rated at was off by a ton. The Crosby alloy shackles are only 1.47 times as strong as normal 3/4" shackles at 7 tons.
https://www.uscargocontrol.com/Crosby-Anchor-Shackle-Screw-Pin-3-4-G-209A-7-Ton
Just so you know and others that may be following along, you are comparing a shackle that breaks at 70,000 lbs to one that breaks at 47,500 in a system with a steel cable that is typically rated at 9800 lbs breaking. Just to keep things all in the same context. You can't break a Crosby 7/16" shackle with a typically 9500 lb rated winch so anything over that is overkill.
What’s the safety factor on the Warn gear?
When we spec’d hoisting gear we used Crosby because we knew they were at least 5:1.
I had read a while back that recovery gear wasn’t as stringent.
Still most situations won’t even see the WLL.
When we spec’d hoisting gear we used Crosby because we knew they were at least 5:1.
I had read a while back that recovery gear wasn’t as stringent.
Still most situations won’t even see the WLL.
The problem with all of this bullshit is yet again, mixing and matching standards between industries. You mentioned the 5-1 Safety Factor or put another way, 1/5 of breaking is the WLL.
So, if you are going to use a safety factor or WLL from one industry and apply it to recovery, that now means you can only pull on your 5/16" steel winch line with a maximum force of 1/5 of breaking or just slightly under 2000 lbs.
Get in or get out but stop mixing the two up.
Typical 3/8" synthetic winch line has a breaking strength of over 15,000 lbs depending on the manufacturer. (Quadratec's in house rope is 18,000 lbs for example.) Once you go to a snatch block and back to your vehicle that's able to be putting over 30,000 lbs on the tree saver, snatch block, shackles, etc before the winch line breaks. (A 10,000 lb winch will only put 20,000 lbs onto those items in that scenario.) Plus, people use shackles to connect dynamic recovery ropes and metal shackles aren't designed for dynamic loads. Does the 7 ton shackle make a huge difference over a 4 3/4 ton shackle? No. But the cost difference between the two Crosby shackles is insignificant. You only need 3 or 4 of them in your recovery gear, spend the money so you don't wind up with 2 lbs of steel launched at your head at hundreds of miles per hour.
You'r recovery gear should be capable of handling at least 3 times your rigs trail weight but the absolute LAST thing I want to fail is the steel shackle or anything further from the jeep than it (like the tree saver or snatch block). Buy quality USA made products of proper strength rating and mitigate the hazards.
Well, one thing that is clear is you have no idea how winches work, at all. A 9500 lb rated winch reduces its pulling power about 20% per line layer. Most winches have 5-6 layers of line so the top layer is only capable of 2000 ish lbs of pull. That also means due to how winches are rated for full force on the first layer, that once you move past the first 5 wraps on the drum, that only leaves 7-8 wraps where you can actually achieve the rated pulling capacity of the winch. With a 3" drum diameter and that multiplied by Pi to get the length per wrap, that is about 6 feet of line where you can pull 9500 lbs. Once it hops up to the next layer, that is reduced by the 20ish% factor due to the larger diameter or leverage against the motor.
It is almost impossible to achieve the scenario where you can set a recovery up with a snatch block, get it tensioned and then pull at the rated capacity for that 6 or so feet.
So again, you are fucking up the forces and ratings to make your point, albeit poorly.
The US Army Vehicle Recovery Manual uses safety factors of 4 for fiber and 5 for wire rope, but that manual predates modern steels and especially modern synthetic ropes.
Also, take this for what it's worth:
https://surfinjeepsafari.com/articl...commend a Safety Factor,Safety Factor of 5:1.
That doesn't matter. The rated gear needs to be able to handle the maximum possible, no matter how rarely that will occur.
If it doesn't matter then why did so many winches ship with 9800 lb rated winch line on a 9500 lb winch? Because they also know how it works.
The winch line isn't what we're discussing, the shackle, tree saver, and snatch block are. A 10,000 lb winch can put 20,000 lbs of pull onto the tree saver, shackle, and snatch block. You said that's rare and I said how rare it is doesn't matter, it can happen and the gear needs to be able to handle it.
I’m not trying to mix, I just know Crosby is used for hoisting which is a defined safety factor.
I am not familiar with recovery standards and am asking what is used? If anything
If you read the literature for most quality winches, they will explain that winches are not hoists and therefore should not be used for lifting applications. Once that applies, then the safety factors for that industry should not be applied in the same manner.
One should also endeavor to learn how winches work, what forces they are capable of at which line layer and then use that to evaluate what gear should be used. CP is pulling all manner of crap out of his ass to support his position that chinesium shackles are bad while ignoring everything that doesn't support that position. He fully failed to address that in a single line pull a typical 9.5 winch can't break a miniscule 7/16" shackle. Contemplate that for a moment.
Why are we mixing 5-1 safety factors from one industry while fully ignoring that we can't apply them to our winches and still use them?
I never claimed they could. Maybe understand what the other person is saying before arguing against them.
I used to design hoists, defined by able to change the potential energy of an object by our engineering manager. I’m not asking hoist vs winch. And I understand the affects of the layers. I get it that breaking even the Chinese Amazon shackles isn’t really a concern with these loads unless someone is pretty much trying to break them.
I’m just asking if there are any standards for recovery equipment such as the non hoisting rated shackles, snatch blocks, factor 55 rope jewelry...
There are not really any standards other than the ability to apply working knowledge and figure out what is necessary.
Like I pointed out above, if you try and apply lifting standards to recovery, you're almost immediately in violation when you exceed 2000 lbs of pull with your winch.
Chinese stuff still bothers me and putting my life on the line, well I will stick with USA made. While on a Rubicon trip a few years ago my buddy brought a brand new set horseshoe set with stakes. and shoes. We set up a pit and started playing a few games. On one wild throw a shoe bounced and hit a bolder ( on the Rubicon borders are everywhere ) anyway guess what the shoe broke in half. Not that I am processional horseshoe player but in all my 65 years I have NEVER seen a shoe break. Well we all stared laughing and looked a t the box and sure enough it said Made in China, Just something to consider
Did you have a made for game horseshoe instead of a real horseshoe?
From Post #1:
You might find some valuable information in this link to Harry Lewellyn's 38-page Offroad Academy Workbook that I found buried in one of Harry's articles about boltless Coyote beadlocks at the Coyote Enterprises website. Although some of it may seem outdated, basic principles of safe recovery don't change.
https://www.coyoteents.com/wp-content/uploads/2021/02/Recovery.pdf
You might find some valuable information in this link to Harry Lewellyn's 38-page Offroad Academy Workbook that I found buried in one of Harry's articles about boltless Coyote beadlocks at the Coyote Enterprises website. Although some of it may seem outdated, basic principles of safe recovery don't change.
https://www.coyoteents.com/wp-content/uploads/2021/02/Recovery.pdf
The moral to that story is don't buy shackles made from Chinese horseshoes, or put another way, if you think that Warn's anchor shackles are made the same way, you may not be paying attention.
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