snatch straps and missiles

Submitted: Wednesday, Jun 06, 2007 at 07:33
ThreadID: 46340 Views:3000 Replies:10 FollowUps:10
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I follow with interest comments and articles on the subject of snatch straps. I note that fittings are known to break and become missiles and that tests on snatch straps indicate failure rates below spec. Well, I wonder if snatch straps should not break before any fitting does. I’ve a mind to get some rope with known breaking strain and use enough turns to provide a capability to pull vehicle out of trouble yet snap before the snatch strap and more importantly, shackles and pulling points. I would appreciate any comments.

Owen
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Reply By: Mike Harding - Wednesday, Jun 06, 2007 at 07:43

Wednesday, Jun 06, 2007 at 07:43
There is no Australian Standard for snatch straps so, in reality, a strap which the seller says is 9000kg could be anything?

Mike Harding
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Follow Up By: Member - Axle - Wednesday, Jun 06, 2007 at 20:22

Wednesday, Jun 06, 2007 at 20:22
Which in turn makes them the most dangerous things put on the planet!!.
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Reply By: Member - MrBitchi (QLD) - Wednesday, Jun 06, 2007 at 07:49

Wednesday, Jun 06, 2007 at 07:49
Rope will not give the same pull as a snatch strap. The strap relies on it's elasticity to store energy and then "snatch" the other vehicle out. A rope won't do thet.
There's nothing wrong with using snatch straps as long as a little common sense is also employed, but that should be a given in any recovery situation, right???

Use rated shackles and correct recovery points and you won't have any dramas.
AnswerID: 245066

Follow Up By: Member - Roachie (SA) - Wednesday, Jun 06, 2007 at 09:51

Wednesday, Jun 06, 2007 at 09:51
G'day John,
I think you've mis-interpreted what he is suggesting. He is still gunna use a snatch strap, but instead of simply attaching it to the recovery point via a shackle etc, he will add a strong rope (in sufficient quantity of turns so it won't snap easily; but WILL snap before anything else has a chance to).
That's how I read it, anyway.
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Follow Up By: Heefers - Wednesday, Jun 06, 2007 at 18:44

Wednesday, Jun 06, 2007 at 18:44
I concur Roachie, the rope would be used as a weak link between snatch strap and shackle.
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Reply By: Willem - Wednesday, Jun 06, 2007 at 07:51

Wednesday, Jun 06, 2007 at 07:51
Won't the snatch strap still become airborne? If the rope gives way at maximum stretch then surely there will be some recoil. Still, there shouldn't be a projectile attached with the rope breaking. Not a bad idea. Just stand well clear when testing.

Go to my website www.kempen.id.au and click on 4x4 and then scroll down the page to "Close encounter with a Bow Shackle". That is what can happen when you are not doing the right thing...lol

Cheers
AnswerID: 245067

Follow Up By: Big Mike - Wednesday, Jun 06, 2007 at 09:47

Wednesday, Jun 06, 2007 at 09:47
Sadly, a Moreton Island Icon was killed a few years ago while dragging someone out on his tractor. Cant recall exactly but I think it was the vehicles attachment point that came loose, snatch strap with shackle and attachment projectile back towards the Tractor and took the poor chap out.
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Reply By: gottabjoaken - Wednesday, Jun 06, 2007 at 08:50

Wednesday, Jun 06, 2007 at 08:50
A good idea ... a "fuse" for a snatch strap between the stap and any fittings.

But...
Rope has totally different characteristics under steady load and in a snap load situation.

So a rope of a known breaking strain may fail with a much lower load placed suddenly.

IMO that would be very unpredictable, and unless you have the resources to set up repeatable experiments to determine the snatch breaking point you wouldn't know how many turns of rope to use.

And the big unknown - what really is the breaking strain of that bad weld somewhere?? and will it fail after a dozen snatches with no problem - look how strong my truck is - or after three???

Also, as mentioned above, what a fuse" would do is simply make it MORE likely that something would be flying around.

Ken
AnswerID: 245074

Reply By: Big Mike - Wednesday, Jun 06, 2007 at 09:49

Wednesday, Jun 06, 2007 at 09:49
What about the good old fashioned wet towell over the strap, to help deaden (is that a word), the fling if a strap breaks. We use this technique and thank goodness, I haven't seen a strap break yet so dont know if it is really effective or a bit of a wives tale.
AnswerID: 245082

Follow Up By: Member - bushfix - Wednesday, Jun 06, 2007 at 09:57

Wednesday, Jun 06, 2007 at 09:57
it's no good mate, every time I see you post now I am reminded of the 18 stone nude woman on Fraser.....damn....
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Follow Up By: Member - Karl - Wednesday, Jun 06, 2007 at 10:14

Wednesday, Jun 06, 2007 at 10:14
I agree - you need some sort of dampener on the snatch strap to stop it flying about - this is the safest and simplest method.

Karl
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Follow Up By: Member - JohnR (Vic)&Moses - Wednesday, Jun 06, 2007 at 11:22

Wednesday, Jun 06, 2007 at 11:22
I have broken a strap and also a repaired one but fortunatly not a shackle. The strap just whipped under the tractor in this case onto the ground. It would hurt obviously, not penetrate like the metal projectile would. The flat sides tend to slow it down through the air to some extent through mass:restrictions of the air movement.
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Reply By: robak (QLD) - Wednesday, Jun 06, 2007 at 10:13

Wednesday, Jun 06, 2007 at 10:13
Agree with you obee.

Snatch straps should come with a (replaceble) safety device between the snatch strap and its loop, which fails once a certain force is created.

R.
AnswerID: 245090

Reply By: me2@neuralfibre.com - Wednesday, Jun 06, 2007 at 10:55

Wednesday, Jun 06, 2007 at 10:55
The strap is not very heavy and wont do heaps of damage. May do some, but you'l live. The "missle" tends to be the lump of steel attached to the end. For this reason I am leery of shackles on the ends, as if the vehicle mount point lets go, the shackle is still attached to the strap with lots of stored energy.

I prefer to make sure the vehicle has hooks. On the towing vehicle I use a high tensile bolt in the towbar pin hole as a "pin" that won't bend. (Please don't start debate on towvar snatching suitability - it'll never end.) If anything there breaks it's unlikely to become a missile and 12mm Hight Tensile bolt is very very strong.

On the stuck vehicle I prefer to have a hook. Failing that, many options are better than a shackle. The shackles never fail (if rated), but they are the most dangerous item to have coming at you.

Paul
AnswerID: 245098

Follow Up By: Ted (Cairns) - Wednesday, Jun 06, 2007 at 12:16

Wednesday, Jun 06, 2007 at 12:16
..this is why russians still stick to this:



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Reply By: Member - JohnR (Vic)&Moses - Wednesday, Jun 06, 2007 at 11:27

Wednesday, Jun 06, 2007 at 11:27
Obee, something that hasn't been mentioned above is to use a bridle through the loop of the snatch strap. Just a light loop that extends to something at the side or each side that if the end gives way holds it from whipping. I have practiced that a bit. Even a bit of a rope to hold the loops from whipping away, or slow down any end.
AnswerID: 245107

Follow Up By: Member - Greydemon (WA) - Wednesday, Jun 06, 2007 at 12:11

Wednesday, Jun 06, 2007 at 12:11
I use something similar, about four foot of 'nylon' rope with a steel carabiner on each end. One end attached to the vehicle - somewhere other than the recovery point, the other end on the strap with plenty of slack. The same on the other end of the strap AND something hanging on the middle . If the shackle or recovery point breaks the rope stops them, if the strap breaks elsewhere then it won't do much damage and the whatever in the middle will slow it down a bit. The carabiners make attachment quick, I leave them on the strap so they only have to be clicked onto the vehicle somewhere.

In view of your idea JohnR I might change this slightly so that both ends of the rope attach to the car, that will probably be even safer.
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Reply By: Member - Phil G (SA) - Wednesday, Jun 06, 2007 at 22:30

Wednesday, Jun 06, 2007 at 22:30
All the stuff you need is in the shops and is rated - no need to make it up as you go.

To stop bits of flying off and killing the driver or onlooker, you need to take a dose of preventive medicine:

#1 Minimise the force required - clear around the wheels to make it easier.
#2 Use 2 strong/rated recovery points on the front - connect them with an equaliser strap (look this up on the net, or buy a Terrain Tamer Equaliser Strap), and this strap goes through the loop on the snatch strap. The equaliser strap halves the force on each recovery point, and should a point break, the other point will retain the broken bit of steel. This is also referred to as a bridle or sling.
#3 Most people use a square hitch towbar on the rear, because they have a good record for safety. Naturally the towbar manufacturers tell you not to. My preference is to put the strap thru the pin, and keep it simple and safe.
#4 Ideally, your strap should be the "weakest link", and naturally be strong enough for the recovery.
#5 Use the minimum force required to recover the vehicle
#6 Ideally recover towbar to towbar if this is an option.
AnswerID: 245273

Follow Up By: Member - John (Vic) - Thursday, Jun 07, 2007 at 00:08

Thursday, Jun 07, 2007 at 00:08
Spot on Phil.
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Reply By: Sea-Dog - Thursday, Jun 07, 2007 at 10:52

Thursday, Jun 07, 2007 at 10:52
I agree that the "bridal" is the safest option when snatching..... and funnily enough next to none of us use it.... not even me because I am too slack to set it up..

They could be as simple as a heavy dutey tree trunk protector or similar to a second recovery point totally independant of the one the snatch is done off... if the first point comes off the bridal should totally stop the thing before it kills someone! If the strap breaks then it is just a strap.. if it is a strap with a hitch point or half a bullbar on it then that is a different kettle of fish.

Maybe snatch straps should be made with the bridal in them from new.. that would "force" the 4x4 community into hitching it somewhere as a safety measure.
AnswerID: 245351

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