Eventhough
Explorer
This...
And this. I'd rather my synthetic winch line fail before a shackle, hook, or other end attachment failed.
My Planned Recovery Setup
- Thread starter H0LLYW00D
- Start date
This...
And this. I'd rather my synthetic winch line fail before a shackle, hook, or other end attachment failed.
Nonimouse
Cynical old bastard
Just for info:
My winch has a manufacturers noted stall of 9.5kg running 12volts. In actuality on a test rig it will far exceed this. Published stall figures are simply figures; actual real world figures vary so much it's quite scarey.
In it's present guise my winch has an increase of more than 25% HP and 1000rpm no load on the motor (think snatch loadings).
When teaching winching and recovery techniques the process allows for working form the weight of the vehicle as a know factor.
There are two calibration schools of thought on recovery that lead the way; the first is the British Military Recovery Manual - very clever but far to complicated. Gradings for soil types; workable as percentages of VM; allowances for each degree of slope.
The second is the American Military concept. Three grades. Nice and simple; 100%, 200% and 300% of VM. 300% equates to a door handle level mire. Something that rarely happens. I like this system because it 'rounds up' the figures nicely and it's simple to teach.
It's worth remembering that the kit we use is rated on lifting not on pulling so there is a much greater allowance for excess of SWL. Even on lifting SWL has a factor of 3, 5 or 7 depending on manufacturer.
I haven't worked Stateside for many years so I'm not up to date with your HS&E stuff. We use LOLER as a guideline http://www.hse.gov.uk/pubns/indg290.pdf but it is not mandatory as there is no true lifting involved
All our strops and ropes should be marked with an inspection tag for manufacture date, SWL, WLL, and the BSS mark (note 'should' not must)
I always allow for split loads on shackles - ie the use of a bridle
I always use individually tested 'c' shackles
However if my max weight 3 tonne 110 is only stuck up to the axles I only require approx 100% of weight in pulling power to move it (give or take and don't forget the tree root wedges on the back axle that I can't see) so a 4.75 SWL shackle is fine for the double line pull....
It's rare that anyone gets stuck that bad - yes it does happen but it's rare. In reality few people are dumb enough to sit spinning tyres and digging the vehicle further into the bog. You lose forward motion, try to reverse and fail, try again in a different gear or ratio; hey presto it's recovery time! Few people are dumb enough not to have pre-empted the situation and prepared...
I use synthetic rope. Not just becuase it's lighter, easier and safer but it makes for a nice 'fuseable link'. It will fail before the recovery points or the big heavy shackle. It's light enough to keep a spare or two in the back of the truck as well. Even my extension rope is a five minute job to turn back into a winch rope.
I'm a great believer in 'Snatchum Straps' and very careful use of KERR. I have three KERR in the truck when going somewhere boggy. One ful length and two half length. They make very good tow ropes as well - the spring takes out the jerking and snatching on long distance tows very nicley
I always cary a couple of Waffle Boards http://www.tracmat.com/ I have two very short ones and two that are 53" long for those special times
My recovery kit fits into two Arco Buffalo Bags http://www.arco.co.uk/products/31B1002/335563/Buffalo+Hard+Bottom+Tool+Bag
Easy to carry, cheap and the plastic base has many uses...
As for pulley blocks or snatch blocks (the former is the correct name) I will only use Black Rat. They are the same as the old ARB pulley blocks. Not only are they very strong but they are easily field stripable. The are also well machined so as to avoid snatch on the synthetic cable
Just my pennyworth
My winch has a manufacturers noted stall of 9.5kg running 12volts. In actuality on a test rig it will far exceed this. Published stall figures are simply figures; actual real world figures vary so much it's quite scarey.
In it's present guise my winch has an increase of more than 25% HP and 1000rpm no load on the motor (think snatch loadings).
When teaching winching and recovery techniques the process allows for working form the weight of the vehicle as a know factor.
There are two calibration schools of thought on recovery that lead the way; the first is the British Military Recovery Manual - very clever but far to complicated. Gradings for soil types; workable as percentages of VM; allowances for each degree of slope.
The second is the American Military concept. Three grades. Nice and simple; 100%, 200% and 300% of VM. 300% equates to a door handle level mire. Something that rarely happens. I like this system because it 'rounds up' the figures nicely and it's simple to teach.
It's worth remembering that the kit we use is rated on lifting not on pulling so there is a much greater allowance for excess of SWL. Even on lifting SWL has a factor of 3, 5 or 7 depending on manufacturer.
I haven't worked Stateside for many years so I'm not up to date with your HS&E stuff. We use LOLER as a guideline http://www.hse.gov.uk/pubns/indg290.pdf but it is not mandatory as there is no true lifting involved
All our strops and ropes should be marked with an inspection tag for manufacture date, SWL, WLL, and the BSS mark (note 'should' not must)
I always allow for split loads on shackles - ie the use of a bridle
I always use individually tested 'c' shackles
However if my max weight 3 tonne 110 is only stuck up to the axles I only require approx 100% of weight in pulling power to move it (give or take and don't forget the tree root wedges on the back axle that I can't see) so a 4.75 SWL shackle is fine for the double line pull....
It's rare that anyone gets stuck that bad - yes it does happen but it's rare. In reality few people are dumb enough to sit spinning tyres and digging the vehicle further into the bog. You lose forward motion, try to reverse and fail, try again in a different gear or ratio; hey presto it's recovery time! Few people are dumb enough not to have pre-empted the situation and prepared...
I use synthetic rope. Not just becuase it's lighter, easier and safer but it makes for a nice 'fuseable link'. It will fail before the recovery points or the big heavy shackle. It's light enough to keep a spare or two in the back of the truck as well. Even my extension rope is a five minute job to turn back into a winch rope.
I'm a great believer in 'Snatchum Straps' and very careful use of KERR. I have three KERR in the truck when going somewhere boggy. One ful length and two half length. They make very good tow ropes as well - the spring takes out the jerking and snatching on long distance tows very nicley
I always cary a couple of Waffle Boards http://www.tracmat.com/ I have two very short ones and two that are 53" long for those special times
My recovery kit fits into two Arco Buffalo Bags http://www.arco.co.uk/products/31B1002/335563/Buffalo+Hard+Bottom+Tool+Bag
Easy to carry, cheap and the plastic base has many uses...
As for pulley blocks or snatch blocks (the former is the correct name) I will only use Black Rat. They are the same as the old ARB pulley blocks. Not only are they very strong but they are easily field stripable. The are also well machined so as to avoid snatch on the synthetic cable
Just my pennyworth
maxama10
Welcome to Nevadafornia
Probably ought to add a chainsaw to that list, may as well if you're carrying the rest of that.
It seems you don't understand what I'm saying. Yes, the sling hook is weaker than a good shackle. But the hook only ever has a single line pull on it.
When using a snatch block to do a double line pull, the shackle on the far side of the winch, the one attached to your tree strap, is subject to double the line pull. You don't have to worry about a 7/8" strap fitting into a thimble. You are using it in the eye of the snatch block, and it does fit easily.
For only a few dollars more than a 3/4", it just makes sense to me. As Nonimouse explains, it's not likely to ever need that much force to unstuck a truck, but... there's not good reason not to use one.
I do understand what you are saying. And I quoted your original post to illustrate the point I was making.
You are using a snatch block with a 20,000 WLL, attached to a strap with a 25,000 tensile. If you apply, the likely 4:1, to your tree strap that is applied to your snatch block, that 4 3/4 WLL shackle is plenty. If we are going off WLL only. But we arent, we interchange WLL and Tensile like they are meant to work together.
Side note: I doubt your snatch block has a 20,000 WLL. It is more than likely 20,000 limit. If you have a snatch block with a 20,000 WLL based on a 4:1, you are looking at something than will have a tensile greater than 80,000 pounds. These dont even have WLL near 10 tons and I would wager they are beefier than whats in your recovery kit.
I understand what you are getting at... For a few dollars more there is peace of mind knowing your gear is strong. But why stop at at 7/8 shackle? Why not get a 1" or 2" shackle? At some point weight, size and useability also factor into the equation.
A 4 3/4 ton shackle is strong enough to use with a 20,000 pound rated snatch block. Because its failure point is 38,000 pounds and most products with a WLL have been proof tested to twice the WLL. But see above regarding your 20,000 snatch block. Post up a pic of it as well. Perhaps it is one of the heavier duty ones.
EDIT: I did find these. Kinda makes the 4 3/4 ton shackle look even better given the tensile points are the same.
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dzzz
™
I think more than one snatch block is excessive unless one is doing some unusual travel. One simply should not try to carry everything they might need. In fact one literally cant carry everything one might need.
A smaller kit and corresponding credit card balance is more fun. The brains to not drive into the giant mud hole without first checking it out is free and weightless.
The snatch blocks sold to "enthisiasts" are often rated at average breaking strength. Commercial snatch blocks are rated much more conservatively. This indicates to me that the "enthusiast" snatch blocks aren't used much, and are more about the bling.
I did make sure all my real ratings were adequate for projected load. The additional weight and size is a PIA. But I would rather have less good stuff than a whole bunch of mediocre gear.
A smaller kit and corresponding credit card balance is more fun. The brains to not drive into the giant mud hole without first checking it out is free and weightless.
The snatch blocks sold to "enthisiasts" are often rated at average breaking strength. Commercial snatch blocks are rated much more conservatively. This indicates to me that the "enthusiast" snatch blocks aren't used much, and are more about the bling.
I did make sure all my real ratings were adequate for projected load. The additional weight and size is a PIA. But I would rather have less good stuff than a whole bunch of mediocre gear.
Metcalf
Expedition Leader
I would have to agree....
It's WAY to easy to take WAY too much stuff. A lighter vehicle is a happier vehicle. Look through everything you have an try to think of different ways to use the same gear....
Will a tow strap function as a tree strap if you need it to...yup. Is it the perfect length and perfectly static...no.
Know more....carry less
It's WAY to easy to take WAY too much stuff. A lighter vehicle is a happier vehicle. Look through everything you have an try to think of different ways to use the same gear....
Will a tow strap function as a tree strap if you need it to...yup. Is it the perfect length and perfectly static...no.
Know more....carry less