Straps and Shackles

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miktdish said:
Yes. A friend needed to move a 40' high cube container across a concrete slab by 10' so he could get another one in.
The container wieghs 4000kgs and was sat on some steel spreader plates.
It was full of wood at the time which I was told weighed 20 tonne but I think that was exaggerated.
We has a load more spreader plates to play with and some 1200x900x10mm Hardox sheets.
I have a Goldfish winch rated to 11500lb (5216kg) with 11mm Dyneema rope (5896kg).
I use 5/8" rated 3.25T, green pin shackles and 3 ton (WWL) lifting slings and straps.along with a couple of 10ton recovery straps which I use to connect to anchors/wrap around trees.

I have several diffent snatck blocks, mainly 'stamped' 8 ton and also use pulley wheels that fit the pin of a 3.25T rated shackle.
There are loads of videos and stuff on UTube and lots on the mechanical advantage gained from using pulleys.

I try to calculate a 3 ton load on the winch. The D90 with the brakes locked on and a couple of bricks in front of all 4 wheels normally suffices as the 'limit', ie if it rides over the briks i'm around 3 ton.

From the winch to 1 corner, through a pully to another container, back to the center leg, through another pulley back to another pulley attached to the back corner, through a pulley to a tree (which I moved to a forklift as it started to bend).
I use 2 ton lifting slings to attach the pulleys
6 lines each taking 3 ton

We needed to encourage the container to move the first few mm and put some oil on the speader plates to quiet the squeal plus stick some wedges under one of the anchor containers to stop it moving, but we got there.

Heres a pick of the low-load pulley blocks.

View attachment 239629


I also use these ... https://goodwinch.com/product/swingaway-pulley-block-3/ which I much prefer to the std 'Orange/Red' Rhino Winch types with the small axle...
Most pulls I do use at least 1 pulley/block, often two - winch, load, anchor back to load.
Click to expand...

Ok so this has taken me a while to work, in my (fag packet head) and since you have edited, no worries.

I would love to see your fag packet workings on this. As I see it you went over the SWL (I didn’t say the tested load) of pretty much everything you used, except your 8t snatch blocks.

What is the rating on those “low load pulleys”?

I am asking as it needs to be asked for peeps that come along and just find something on the net.

J
 
marjon said:
Ok so this has taken me a while to work, in my (fag packet head) and since you have edited, no worries.
I would love to see your fag packet workings on this. As I see it you went over the SWL (I didn’t say the tested load) of pretty much everything you used, except your 8t snatch blocks.
What is the rating on those “low load pulleys”?
I am asking as it needs to be asked for peeps that come along and just find something on the net.
J
Click to expand...

There is a whole raft of stuff on the mechanical advantages of using blocks but in simple terms it's like this ...

Lets say the load is 6 tonne.
The landrover has a winch
Winch to load = 1 line
To move the load the winch produces 6000 kgs which is transfered to the load and the winch.
In this scenario the landrover would get dragged towards the load.

Next we take the winch rope to the load and come back, through a pulley, towards the landrover and attach the rope to the landrovers recovery point.
Winch to load = 2 lines. The same 6000 kgs of pull is applied.
We still don't move the load as we are still sharing the load between us but now we move together at half the speed. The load is still on only 1 rope as the line from the winch to the first pulley is simply changing the direction of pull.

Instead of attaching the 2nd line back to the recovey point on the same landrover with the winch, we attach a pulley to an anchor (another landrover for example) and pass the rope through that and go back to the load.
Now the load has 3 lines attached to it. 1 (from the winch) and two supporting the load to two anchors.
We produce 3000 kgs of 'pull' from the winch and the 6000 kg load moves.

If we added another pulley to the load and took that line back to another anchor (a tree this time) we would only need 2 ton on the winch to move the 6 ton load.
Add another pulley at the tree and go back to the load and now you need only 1.5 ton on the winch.

Another pulley - 1.2 ton
Another - 1 ton

Haltrac Hoists typically have 8 pullys wheels (or sheaves) and the load is therefore moved with a 8:1 ratio.
1 ton lifts 8 ton
125kgs lifts 1000 kgs, you can easily lift a landrover engine out of the car using a Haltrac Hoist but just pulling on the 'tail'.
Haltrac (and other engine) hoists are typically made up of 2 multi sheave pully frames which have 3 connection points.
#1 is you pulling on the chain/rope/tail
#2 is the frame
#3 is the engine (or load).
The total weight of the load is supported by the frame (or anchor point) and your 'pull' is amplified 8 times so lifting the engine out is easy.
Having more than 1 anchor point splits the load (equally) between them.

So: (Fag Packet = simple division) Load Wieght/number of pulleys = pull on landrover required to move the load.
6000/3 = 2000
6000/6 = 1 ton

Do I need to "beef up" my D90 recovery points = No
The various recovery points/bumper/chassis legs/dumbirons etc will take around 9000kgs before they deform. My winch and line is rated @ 5000kgs (with margin).
My D90 weighs approx 2500kgs, in gear with the brakes on and a brick/chock at each wheel it needs around 3000kgs to move it (might be a but less but hey ho, safety) so I know when I winch 'in' and the landy tries to climb over the bricks i've reacherd about 3 ton.
2 pulleys I move 6 ton
4 pulleys I move 12 ton
If I tie the back of the landy to something I can pull circa 20 ton - all within a safety margin.


marjon said:
What is the rating on those “low load pulleys”?
Click to expand...

They are not rated.
They are not designed for 'lifting'.
I have some 50mm sheaves on a 2T WWL shackle and a 90mm sheave on a 3.25T shackle.
The shackles are 5:1 rated.
The sheaves likely to be no more than 5 tonne - i've not broken one yet . If it does collapse i'm not overly concerned as the pin of the shackle will 'save' the day.
 
miktdish said:
Yes. A friend needed to move a 40' high cube container across a concrete slab by 10' so he could get another one in.
The container wieghs 4000kgs and was sat on some steel spreader plates.
It was full of wood at the time which I was told weighed 20 tonne but I think that was exaggerated.
We has a load more spreader plates to play with and some 1200x900x10mm Hardox sheets.
I have a Goldfish winch rated to 11500lb (5216kg) with 11mm Dyneema rope (5896kg).
I use 5/8" rated 3.25T, green pin shackles and 3 ton (WWL) lifting slings and straps.along with a couple of 10ton recovery straps which I use to connect to anchors/wrap around trees.

I have several diffent snatck blocks, mainly 'stamped' 8 ton and also use pulley wheels that fit the pin of a 3.25T rated shackle.
There are loads of videos and stuff on UTube and lots on the mechanical advantage gained from using pulleys.

I try to calculate a 3 ton load on the winch. The D90 with the brakes locked on and a couple of bricks in front of all 4 wheels normally suffices as the 'limit', ie if it rides over the briks i'm around 3 ton.

From the winch to 1 corner, through a pully to another container, back to the center leg, through another pulley back to another pulley attached to the back corner, through a pulley to a tree (which I moved to a forklift as it started to bend).
I use 2 ton lifting slings to attach the pulleys
6 lines each taking 3 ton

We needed to encourage the container to move the first few mm and put some oil on the speader plates to quiet the squeal plus stick some wedges under one of the anchor containers to stop it moving, but we got there.

Heres a pick of the low-load pulley blocks.

View attachment 239629


I also use these ... https://goodwinch.com/product/swingaway-pulley-block-3/ which I much prefer to the std 'Orange/Red' Rhino Winch types with the small axle...
Most pulls I do use at least 1 pulley/block, often two - winch, load, anchor back to load.
Click to expand...
That's a lot of fuking about and all dependent on a gut feeling of bricks chocking wheels.

Why didn't you ask the hi-ab delivery driver to lift the old container to its new position with the truck he delivered the new container on?
 
Hippo said:
That's a lot of fuking about and all dependent on a gut feeling of bricks chocking wheels.
Why didn't you ask the hi-ab delivery driver to lift the old container to its new position with the truck he delivered the new container on?
Click to expand...

Not a gut feeling, playing with a weigh bridge :)
Couldn't put the high-cube down cos there was a wall in the way. An iron fairy would have reached
 
miktdish said:
Not a gut feeling, playing with a weigh bridge :)
Couldn't put the high-cube down cos there was a wall in the way. An iron fairy would have reached
Click to expand...
How does a weigh bridge measure the weight of a pull, friction coefficient etc? Not alot adding up here. Talks a good game though.
 
gstuart said:
must admit have never used a kinetic rope due to the dangers, always taken up slack very slowly and applied a steady pull not floored it as don’t fancy having something go through the back of my landy
Click to expand...
Personally I think the dangers of KERRs are very misunderstood. Anything you do with a KERR that is dangerous, would be equally as dangerous with a strap or non-KERR rope.

Also sometimes you can't just take up the slack and apply a steady pull. It depends on the terrain and how much traction there is, plus how stuck the vehicle is. It is perfectly possible that the recovery vehicle will just spin its wheels. Which means you won't be recovering a vehicle in that manner.

BTW - I think you posted about tow balls previously. These are heavily used in off road competition in the UK. For competitions regulated and sanctioned by the authorising body the MotorSport UK (aka MSA).
 
300bhp/ton said:
Personally I think the dangers of KERRs are very misunderstood. Anything you do with a KERR that is dangerous, would be equally as dangerous with a strap or non-KERR rope.

Also sometimes you can't just take up the slack and apply a steady pull. It depends on the terrain and how much traction there is, plus how stuck the vehicle is. It is perfectly possible that the recovery vehicle will just spin its wheels. Which means you won't be recovering a vehicle in that manner.

BTW - I think you posted about tow balls previously. These are heavily used in off road competition in the UK. For competitions regulated and sanctioned by the authorising body the MotorSport UK (aka MSA).
Click to expand...
As in my pictures and description, I had little traction and he had none. I backed up and gave it some and out he popped as he gained traction. In many peoples eyes, this was 'dangerous' and they would be correct.
In my eyes, it was a calculated (I say gut feeling but it seems to upset some who don't understand that gut feelings come from 40 years experience) risk and it payed off.
No I didn't mention tow balls but others have in this thread. I don't like the idea but I have used the lower pin to pop a sling in on a lower force tow.
 
My Old Landy said:
As in my pictures and description, I had little traction and he had none. I backed up and gave it some and out he popped as he gained traction. In many peoples eyes, this was 'dangerous' and they would be correct.
In my eyes, it was a calculated (I say gut feeling but it seems to upset some who don't understand that gut feelings come from 40 years experience) risk and it payed off.
No I didn't mention tow balls but others have in this thread. I don't like the idea but I have used the lower pin to pop a sling in on a lower force tow.
Click to expand...
see thats it.. a risk assessment isn't about removing all the risks, its about calculating whats acceptable and how to work with the risks
 
My Old Landy said:
As in my pictures and description, I had little traction and he had none. I backed up and gave it some and out he popped as he gained traction. In many peoples eyes, this was 'dangerous' and they would be correct.
In my eyes, it was a calculated (I say gut feeling but it seems to upset some who don't understand that gut feelings come from 40 years experience) risk and it payed off.
No I didn't mention tow balls but others have in this thread. I don't like the idea but I have used the lower pin to pop a sling in on a lower force tow.
Click to expand...
Do you have a reading problem? ;)
 
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