Power of the Snatch Block

John
Thanks for sharing the story, good photo's and diagram.

Have a good one

John,

Thanks for that. Have filed that one away - may come in very handy one day. Not that I anticipate rescuing an excavator, but do like the snatch block usage.

Regards, John.

Works just like a crane, a 50 ton crane winch only has a 5 ton line pull it runs over a series of sheaths and thats how it can lift 50 ton.
Awesome mechanic's really.
Great photo's.

Cheers Scoof . :-)

Takes me back to my Army Recovery days. There is another one to this Compound set up where you use 2 vehicles, which is called a Compound Compensating Tackle Layout whereapon it will keep the recovered vehicle in the exact line that you want while it is being recovered. This can also be used when the recovered vehicle is being pulled along a slope with the risk of it going sideways.

This does look very impressive. The layout of using tackle blocks is good to see.

A couple of questions that don't seem just right.

Who has a winch on a landcruiser used for towing cars that is only 2300kg. Most winches people fit are around 10,000kg.

Another thing - I have seen those excavators doing all sorts of work and never seen one get bogged yet. If they do sink they just spin around and use their boom to push themselves up and out.

Also they had a second excavator right next to it on timber sleepers - why not just haul the bogged one out with that one rather than using a tiny landcruiser.

David

To me this doesn't add up.

For a start as a previous post says a 2500 kg winch is more likely to be on a Suzuki than a Landcruiser.

Why you would use a puny winch like that when you had far more robust equipment on site is unclear.
The ground couldn't have been too soft for the second excavator as it got close enough to dig the racks of the bogged excavator clear.
The claimed 12x pull of the set up is simply incorrect. Although the generally accepted view is that a simple snatch doubles the pull this isn't exactly true, there are frictional and other losses involved which reduce the pull. In a compound arrangement as shown these losses will be considerable.
Even given it is 12x the winch pull this would result in a max of 30,000 kg. If the stuck machine weighed the claimed 23,000 kg there is only 7000 klg 'spare'. Combine the weight of the machine and the suction in that bog and I bet it would take much more than 30,000 kg to free it.

And finally what about the safety on site. Anyone that knows anything about winching safety would not, or would not let anyone else, stand on the cable !

Interesting story but a few too many questions to my mind.

Ken

I have seen similar things done to pull trucks out of bogs, a D10 Dozer, and an excavator. Yes, it looks strange, but I believe that what he did was possible. Excavators really have very little pulling power; they are not designed for pulling or towing. Get the bucket stuck on a rock, and you can very quickly turn one over. The hydraulics on the bucket is strong enough to tip the whole thing over. The other thing that helps in this recovery, is that all cables are kept low to the ground, giving direct pull and not lift. The excavator would also have been "driven" out as well, assisting in the winch.

But I agree, there are some anomalies, and un-answered questions. But it is do-able.
regards

Interesting set up, basically would give a triple purchase?.
I used to have a set up off two double sheaves giving 4 times the purchase.
I pulled a 6 tonne tractor that far down it was difficult to get out the doors, using a small tractor with a loader as anchor and using the Land Cruiser to do the pulling, didn't even spin a wheel.
It was a good set up, used to keep it hanging on a fence at the shearing shed, neighbours knew it was there and would borrow it if needed, until one day it didn't return.
Sometime later picked up a couple of double sheaves, pins were a bit small though but thought I would turn them out and replace with bigger pins of suitable steel. Gave up the idea when I priced the cable, 25mm ,over 2 grand, so just hung the two blocks on the fence instead.
I think they are still there.

Thanks for the post MrBitchi,

I found it both interersting and informative.

Would it be possible to post a link to the original home site. Would like to have a look at what ever else may be there. Others here may be ale to find the source site but beyond me.

Ian