Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: HIWYH8R on May 28, 2006, 09:04:02 PM
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What is the best way to do this? Would using a shackle be a safe way?
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Actaully no, because if something breaks you are adding another metal projectile to the equation.
The best way is to pull the 2 straps through each other so the looped ends are interlocked. However this is a pain in the bud to do. 2nd option is to use a piece dowelling. Pull 1 strap through the other and use the dowel to hold them together.
Hope that makes sense
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I've heard about the dowel thing but not sure how to do this. I need pictures :) Like trying to tell someone how to tie a knot over the phone heheh.
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Ok, I understand what you are talking about now, after seeing the pics below. I was imagining something else from the way it was described and it would have been more dangerous than what is shown below.
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could you put the two end loops on top of eachother then thread the end of one strap through the two?
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Use a longer strap if possible. If not possible, I'd say use a shackle.
A shackle is more secure than a dowel will ever be, and tying two straps together at the loops does nothing but create a weak point. Where as a shackle doesn't remove strength from the strap so long as it's the proper duty rating.
Annnnnnnd I've seen a snapped 130,000lb tow strap (I believe they're sand surrounded kevlar ropes or something, they're made for crane lifting) that was shackled into a 150,000lb tow strap, when it snapped, the strap fell to the ground.
We were using it to pull a Cat 980 loader out of a sump...
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The last run I was on we had to do this and we used a branch about 5 inches thick and looped the loops of 2 tow straps toghether and this worked fine and nothing broke and even if it did the wood would not end up flying into someone and kill them like a shackle would.
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There was a post on here about this before, but must have been lost.
Never use a shackle. If anything breaks the energy stored in the straps projects the shackle through the vehicle that is still attached. If anyone is in the path, like the driver, death is the result.
The straps are intertwined at the ends. A stick is placed in the openning to allow them to be separated later. A picture is needed. There was one, but I can't seem to find it.
People really should have some basic training before attempting recoveries.
edit: Found the picture
This method makes a joint that is as strong as the strap and can not come apart. The stick prevents the the strap ends from becoming jammed together and allows them to be easily separated after the pull. The stick is not taking any load.
(http://members.shaw.ca/red90/straps.jpg)
edit2: A link on the subject: http://www.4wdonline.com/A/Snatch.Strap.html
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Use a longer strap if possible. If not possible, I'd say use a shackle.
A shackle is more secure than a dowel will ever be, and tying two straps together at the loops does nothing but create a weak point. Where as a shackle doesn't remove strength from the strap so long as it's the proper duty rating.
I cant find the link, but there was a jeeper killed using this method just a few years back.
A busted strap under tension can turn a shackle into a bullet.
Please, never use this method, or recommend it to anyone.
Use a peice of wood, or dont use anything. Its not that bad digging them apart with a flathead screwdriver.
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Use a longer strap if possible. If not possible, I'd say use a shackle.
A shackle is more secure than a dowel will ever be, and tying two straps together at the loops does nothing but create a weak point. Where as a shackle doesn't remove strength from the strap so long as it's the proper duty rating.
Annnnnnnd I've seen a snapped 130,000lb tow strap (I believe they're sand surrounded kevlar ropes or something, they're made for crane lifting) that was shackled into a 150,000lb tow strap, when it snapped, the strap fell to the ground.
We were using it to pull a Cat 980 loader out of a sump...
Most of the tow straps offroaders use are designed to stretch and snap back. Now just imagine a tow strap stretched out with a shackle on the end when it lets go, just like a winch cable when it lets go. I have seen a video of one that let go and the shackle went flying through the back window and almost the windshield off a truck.
Lifting straps are not designed to stretch, so no stored energy, plus they are not design to be used as a tow strap. Listen to Bnine on this one.
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Because this post is so good, you need to read it again 8) .
There was a post on here about this before, but must have been lost.
Never use a shackle. If anything breaks the energy stored in the straps projects the shackle through the vehicle that is still attached. If anyone is in the path, like the driver, death is the result.
The straps are intertwined at the ends. A stick is placed in the openning to allow them to be separated later. A picture is needed. There was one, but I can't seem to find it.
People really should have some basic training before attempting recoveries.
edit: Found the picture
This method makes a joint that is as strong as the strap and can not come apart. The stick prevents the the strap ends from becoming jammed together and allows them to be easily separated after the pull. The stick is not taking any load.
(http://members.shaw.ca/red90/straps.jpg)
edit2: A link on the subject: http://www.4wdonline.com/A/Snatch.Strap.html
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JohnB is absolutely correct, this is the only safe way to join two straps, takes alittle more time to configure them but is easy once you try it.
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Here's a great link for anyone who hasn't read BillaVista's Recovery Bible before:
http://www.pirate4x4.com/tech/billavista/Recovery/
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Ok but then what do you use for tow points then? Most people I've seen use shackles on their bumpers and if one breaks same thing happens, a projectile. Same as hooks, even bolted with Gr.8 bolts.
Would also like some good recovery web pages besides that old army one and the few small incomplete web pages on the subject.
Edit: Ok just started reading Redbulls link. Very good reading.
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I've always thought about this when looking at custom bumpers.
(http://www.pirate4x4.com/tech/billavista/Recovery/shackle%20loads.jpg)
and wondered why so few people follow this practice...makes so much sence to me...
On the tow hook thing...the shear strength of a Gr. 8 bolt let alone two far exceeds the yielding point of a 10,000lbs tow hook. That said to achieve this the tow hook must be properly installed. Bolts get there strength from the bolts themselves plus the friction between the two objects they are holding togethor. It is very important that a tow hook not be lose and able to slide back and forth under load for this will lead to premature fatigue in the bolts.
Speaking strickly from opinion and not experience I much prefer tow hooks. I've seen pictures of tow hooks that bend and then simply release the strap. While this is not ideal, in my mind it is much safer than launching a rather large projectile (shackle) into the air.
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Ok but then what do you use for tow points then? Most people I've seen use shackles on their bumpers and if one breaks same thing happens, a projectile. Same as hooks, even bolted with Gr.8 bolts.
First it is normally the strap that snaps, not the shackle or tow hook. If you have a shackle in the middle of two straps it will fly to the other side! If it is mounted properly to a bumper it, will probably stay there.
Also, it best to have less flying pieces as possible.
I only use 3/4" shackles and am worried when I see people using 1/4" shackles :roll:
The tow hook arguement makes sense to me, as I've seen one bend.
ps, your shovel may be nicer, but mines more muddy :twisted:
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Yes, it is important that the rigging hardware and the attachment points are substantially stronger than the strap or cable.