Nature nearly won this one!

An insight into the pre-digital photographic age at a time before the Recovery Industry was engulfed in legislation by bureaucratic busybodies.

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mick
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Nature nearly won this one!

Post by mick » Fri Oct 31, 2014 2:31 pm

I think this is one of the hardest jobs we have ever done. It was several years back down on the West Sussex/Hampshire border. We have done many diggers in ponds and river bottoms etc. These are comparatively easy as you can either drain the pond/stop the river etc and if a ramp is formed, you simply increase the winching power enough to overcome the resistance and the casualty simply sledges out to hard standing.

The area that the machine is stuck in is called 'The Pie'. It is called this because it has a hard crust but once you've gone through that there is nothing substantial at all. Actually, it's worse than a pie because as far as I'm aware there is no bottom to this silt. It would easily swallow this machine forever and I am aware that before we got there, it had been a consideration to drain the fluids and let the machine disappear out of sight.

The area is classed as an SSI (special scientific interest) as it has quite a lot of rare species inhabiting it. It is maintained by the environment agency. Periodically, a machine is sent out there and is used to clear out the waterways that meander across the surface. The max. weight of machine used does not normally exceed 13T on wide tracks. Unfortunately an outside contractor was used, they employed a 24T machine on standard tracks with a driver who is not used to these conditions. The experienced machine operators who normally carry out these tasks have created a method to prevent things like this happening. They never track over the same area twice and they are fully aware that if the machine starts to break the surface of the pie, they cannot spend long trying to drive the machine out. They would normally employ a winch at an early stage. They also use bog mats (several railway sleepers bolted together) to spread the load. None of this procedure was adopted on this day!

It took 3 days (including machine transport) to get the machine away from natures claws. It was over 100m from anything that resembled hard standing. It was sinking by around 4-5ft a day on its own and was listing badly in the process. The engine had failed and the boom was in the fully
raised position. Unfortunately, it had been attended by others before we were called. They had made a fatal mistake of trying to winch the machine from the towing point underneath the turntable. This resulted in the machine taking similar action a plough share and burying the tracks further underneath the surface of the pie.

I felt it was one of those jobs that you have to get right first time or you will never accomplish the task. The machine had to be raised dramatically at the same time as being pulled. To simply winch it out would be catastrophic. The machine would have gone down rapidly, the load on any winching equipment etc. would have been constantly increasing until it became immovable. You can picture the situation in as much as the weight is unsupported, a long way from the winching vehicles and it has already passed under the 2 or so foot of 'crust'. To further complicate matters, there was this listing problem.

I decided to use bog mats to get a lighter machine near to the casualty and attempt to uncover the end of the track chains. This is always the best place to pull a stricken machine if you want to slide the tracks out, it's like getting hold of the tip of someone's ski's to pull them compared with pulling them from the waist when the tip of the ski is buried. All the time we were working, the casualty was sinking and our 13T machine also started to sink even with its mats, as the surface strength was now compromised.

Eventually we managed to pass chains through behind the track sprockets and then set to building a massive stack of bog mats, with the intention of dissipating the downward load caused by the winch cables passing over the top. The stack was at least 4 mats high and probably 3 wide by memory. They were arranged in a pattern that would hopefully keep some form of order even though we knew they would become displaced. The 13T machine was also used to force two bog mats on an angle as an attempt to give the machine something to slide up when it was winched out of the hole. Two winch tractors were employed, one at either side anchored to a high part of the boom to keep the machine upright. This was essential as the silt offered no stability whatsoever, and it was clear that the machine would have fallen over as the recovery progressed.

It was difficult to calculate exactly how much winching effort would be required. It was a 24T machine in heavy silt. It needed 'lifting' as much as pulling and the lift would be a sudden one. It was so far from the edge of the swamp, we were utilising virtually all the chains and equipment we then had. It also needed winching via two sources (two winches) as it wasn't quite in line with where we wanted it to finish up. We used two field cables for the majority of the distance, and employed a form of compound winching to provide the effort required.

The old Autocar and the Peterbilt (V100) provided the winching effort. Both had to be towed into position with the 360 digger. We had so many blocks employed that we had to adjust cable lengths etc. several times to complete the pull.

All the bog mats slid and got tangled up etc. but still managed to provide enough support for the machine to rise out of its imminent demise. The two tractors had a difficult job working in unison as they had to continually balance the unstable machine that was moving both up and away from them. Once the machine was out, it was a relatively simple but time consuming job of placing a temporary road of bog mats and winching it to hard standing.

As I mentioned earlier, don't make the mistake of comparing this situation with one where the casualty is either submerged or stuck in a position where there is a 'bottom' i.e. pond or riverbed.

I have got some more pictures of this, if I find them I'll post them up.




This is what we were faced with, at least 100 yards from any form of hard standing. The surface had become completely destroyed by other failed attempts. It was sinking by around 5ft per day.

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Looking into the hole standing on the beginning of the bog mat stack!

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Sinking at 5ft per day, it was on the point of being irretrievable.

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This is a big machine, weighing 24T with its boom fully raised. The cable attached to it is purely holding it from sinking out of sight.

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The trucks had to be pulled into place by the 13T digger.

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This was the only area we had to work from. Anywhere other than this is totally out of bounds.

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Really not pretty at all, but we were using virtually everything we had. Planks were put down to walk on as you couldn't stand for long without sinking down into the silt.

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2nd vehicle (Peterbilt) in place alongside the Autocar.

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It looks like a gruesome murder scene, doesn't it!

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The tubby man put the machine in this situation!

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Looks pretty pleased with himself :P

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We had to pump water continually as the hole kept filling up.

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This indicates the stability issue we had.

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Starting to emerge from its silty grave.

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Approaching the top of the slope.

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Winch tractor miles away!

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And it's out!


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You can now see the angled bog mats.


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The old Autocar and Peterbilt (when it was nearly new!) which carried out the 'rescue'.

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