desperately looking for some special informations about the Mark IV.

[Oliver Brüninghaus]

Hi,

well this might probably be more a question for the tank archeologists and keepers of the holy grail.

Working on a new unditching beam I’m looking for some informations how the beam was attached to the track plates.
I have been searching the web for years but have not been able to find any sufficient information.

Based on the attachment of the grousers I have come up with an idea of how it might have been.
If anyone could shed some light on this I would be very grateful.


Best Regards
Oliver

For a first impression I have laid everything together.

The sketch shows two clamps which are screwed to the middle iron with the eyelets for the chains. No idea if it could have been like this.

[Tim Biersma]

Hi

You could ask craig moore on Facebook.
He's in the tank museum library more often than not.
So he might be able to find out.

Greetings tim biersma

[Chris Hall]

Personally, I wouldn't ask Craig Moore. He's a plagiarist, just regurgitating other people's research for his own profit. I've had personal run-ins with him.

[Chris Hall]

Oliver -

Your design would solve the problem from an engineering perspective, but isn't practical for battlefield use .........

The unditching beam was mounted on top of the Mark IV during the Ypres battles in mid-1917. To connect it required a member of the crew to climb on top of the tank under fire - probably an instant Military Medal ! By Cambrai, the beam had been remounted at the rear, giving much more protection. A crewman could then climb out of the little back door to do it. And on the Mark V it could be done from within the little conning tower on the top. So it must have been quick and simple, especially under fire and when the tracks are full of mud (fitting the spuds was a nightmare, and that was done before going into action !).

I don't know where I've seen it, but I think there was a sort-of clip that slid under the tracks and connected with the bolts, thus being dragged around the tank and back to the mounting point. The design I remember seeing looks very like the clip that holds the track chains together - like a serrated U clip. That could be pushed in and pulled out with just brute strength - no spanners anywhere !

Of course the unditching beam didn't always work - some crews didn't even bother to try, just dismounting the Lewis guns and joining the infantry. And I doubt the Beutepanzer crews bothered either - they were usually fighting over better ground (after Amiens) for a start. And abandoning a tank wasn't a problem for either side - there were plenty more, either being built in the UK or being stripped down at Charleroi.

Let us know what you think.

Best wishes, and stay well,

Chris

[Mark Heaps]

Having crewed ChARV, ChARRV & CrARRV and being involved in a few tank recoveries, I would like to put some input into how the un-ditching beam could have worked and should have been employed.

The rails at the front of the tank may suggest to the un-informed that the beam was dragged by the tracks to the front of the tank to give it extra traction, unditch & continue the advance.

From a recovery viewpoint, this is wrong. Anything in front of the bog-in point is un-known ground. Everything directly behind the tank prior to it bogging in was proven good ground.

On a MkIV, attach the un-ditching beam to the tracks & then reverse. Good chance that it would have worked & the rails at the front would have recovered the beam for it to be re-used fot the next time it was needed.
Once the tank had unditched, then up to the commander to find a better route bypassing the trouublesome ground immediately in front of him.

[Chris Hall]

Mark -

That may well be the solution - today. But that’s applying 21st Century experience to a problem faced over 100 years ago, where they were making it up as they went along.

WW1 practice was to hitch the unditching beam at the back, drag it over the top, round the front, underneath the tank to get extra traction and back where it started from. If it didn’t work the crew just abandoned the tank and became Lewis gun teams, as per Standing Orders.

Aren’t we all about trying to recreate history, not correct it ?

And now, back to the original question of how the beam was actually connected to the tracks on a 1917 Mark IV tank ……

Chris

[laurent ROSSET]

- Abou-Ben-Adam mark IV beam (Philippe Gorcynski collection)
- some pics from a building review of the TAKOM 1/35 kit
- Object description
A Mark IV Tank using its unditching gear in crossing a pit on the Testing Ground, Tank Corps Central Stores, Erin, September 1917. Note men of 51st Chinese Labour Company at work on right.
OBJECT DETAILS
Category Photographs Related period First World War (production), First World War (content) Creator Northey (Mr) Production date 1917-09 Catalogue number Q 11655 Part of MINISTRY OF INFORMATION FIRST WORLD WAR OFFICIAL

[Stephen White]

From a recovery viewpoint, this is wrong. Anything in front of the bog-in point is un-known ground. Everything directly behind the tank prior to it bogging in was proven good ground.

This confuses recovery - the extraction of a tank from a bogged condition, usually as Mark observes, backwards - with measures to enhance mobility in a forward direction. The unhitching beam was developed to increase the ability of the tank to overcome obstacles, in particular to give it increased traction at the point of exit from a trench crossing, when the tracks were trying to establish purchase on the far parapet. It was a response to the Germans increasing the width of their trenches when the Hindenburg Line was being dug.

I can see if David Fletcher is able to help with the method of attachment. Wait out as they say.

[Oliver Brüninghaus]

Gents, that's why I appreciate this forum so much.
Helpfulness, expertise, brilliant ideas, a lot of experience and the willingness to share it - that's an outstanding combination !

Tim and Chris,
thank you for the advice and assessment respectively. I am not on Facebook, so I would like to explore other chanels first.

@ Chris,
you are quite right in your estimation that assembling the clamps under fire would be too complicated and tedious. There had to be a quicker and easier way.

I don't know where I've seen it, but I think there was a sort-of clip that slid under the tracks and connected with the bolts, thus being dragged around the tank and back to the mounting point. The design I remember seeing looks very like the clip that holds the track chains together - like a serrated U clip. That could be pushed in and pulled out with just brute strength - no spanners anywhere !

Yes, that is a very interesting approach. Screws and mud just don't mix.
Of the very few surviving operational reports of the Mark IV under german service, I am not aware of any in which the use of an unditching beam was reported. But since the restored tanks in Charleroi were again equipped with undiching beams, I assume that they were also planned to be used.

On a MkIV, attach the un-ditching beam to the tracks & then reverse. Good chance that it would have worked & the rails at the front would have recovered the beam for it to be re-used fot the next time it was needed.

@ Mark,
that is a very interesting point. If you look closely at the picture with the Mark-IV and the hanging unitiching beam in front of it, it seems to have been exactly the same in this training situation. It was manoeuvred backwards out of the pit.
But in action under fire there could have been other orders or tactics at that time.

@ Laurent,
thank you for your inspiring collection of pictures.
I had also used the example of the Takom model and the Mark IV as a guide, but didn't really get any further.
Abou-Ben-Adam - thats the helping hint!
I had forgotten that it existed and did a new Google search.
I have attached the result below (detail enlarged with algorithm).

The unhitching beam was developed to increase the ability of the tank to overcome obstacles, in particular to give it increased traction at the point of exit from a trench crossing, when the tracks were trying to establish purchase on the far parapet. It was a response to the Germans increasing the width of their trenches when the Hindenburg Line was being dug.

I can see if David Fletcher is able to help with the method of attachment. Wait out as they say.

@ Stephen, yes that is a crucial aspect. Torpedo spuds, later the spuds (sometimes I have seen them termed "grousers") and the unditching beam were developed to help the tank move forward, especially on muddy slippery surfaces.

If David Fletcher would like to share his undoubtedly superior knowledge on this particular issue, it would be a wonderful opportunity to better understand this small detail of tank history. Thank you so much for asking him.

We will wait patiently in awe ...


Greetings to all and stay safe
Oliver

[Oliver Brüninghaus]

.

With a small update of what I have discovered so far I would like to bring the discussion forward again.

The unditching beam could have been attached to the tracks in the manner sketched.
Only two long nuts would be needed for this.
This could also have been done quickly under fire.

The most interesting component is the probably forged clamp at the end of the unditching beam's chains, which is attached at the side to the track plates.
All tensile forces converge here and it must be very resistant.

If anyone can provide any other helpful hints like pictures, food for thought or measurements that would be great. Maybe such a strange piece of metal has already been found and is lying around unnoticed.

Regards
Oliver

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