Landships II

Centurion · Legend

Asymmetric unditching rails

Mark Hansen · Legend

I think that the apparent asymmetric kink is an optical illusion. Where an unditching beam is visible, the rails run beneath it at the same position left and right. I checked photos of Mk V's and V*'s and when the photo is taken from one side of the tank, that is the side that appears to have the straighter rail. The kink is on both sides to allow clearance of the openings on the sides of the rear cupola.

Centurion · Legend

Mark Hansen wrote:

I think that the apparent asymmetric kink is an optical illusion. Where an unditching beam is visible, the rails run beneath it at the same position left and right. I checked photos of Mk V's and V*'s and when the photo is taken from one side of the tank, that is the side that appears to have the straighter rail. The kink is on both sides to allow clearance of the openings on the sides of the rear cupola.

Sorry but I'll take more convincing - you can't actually see a clear view the tracks under the angle of the kink and there is an extra bend in the rails on that side.

Roger Todd · Legend

I believe that Mark Hansen is correct in his interpretation of the optical illusion. Here is a well known photograph that shows two tanks with kinked rails very clearly on the left-hand side, with the right sides being susceptible, I think, to Mark's interpretation - unless you believe that for some reason some tanks had only a right-hand rail with a kink, and some had only a left-hand rail with a kink...

-- Edited by Roger Todd at 20:00, 2006-05-14

Centurion · Legend

Roger Todd wrote:

I believe that Mark Hansen is correct in his interpretation of the optical illusion. Here is a well known photograph that shows two tanks with kinked rails very clearly on the left-hand side, with the right sides being susceptible, I think, to Mark's interpretation - unless you believe that for some reason some tanks had only a right-hand rail with a kink, and some had only a left-hand rail with a kink... -- Edited by Roger Todd at 20:00, 2006-05-14

I think you'll find in this case that the port side kink is vertical to protect the exhaust pipe. I'm endevouring to collect images of unditching rails and so far it looks very much as if there were no kinks, port side only kinks, starboard side only kinks, vertical kinks and just about any combination one can think of! (very kinky

) I'll put them together and post soon.
So far I have not seen any photos of tanks leaving the factory with unditching rails fitted. Were they fited in France by Central Workshops?

Thomas Buecheler · Captain

Hello Centurion

A quick look at the Central Tank Workshops pages. Page - 9 - of "Central Stores. Period 1st April 1918 - 30th June 1918" states:

".....May 19th. Captain T.E. Wenger assumed duties as O.i/c R. T. & D. During this period Tanks were arriving in large numbers from England by Channel Ferry service, on one occasion as many as 49 arrived on one day and it was usual for 20 to arrive each day of the week.

The section was therefore working at very high pressure and additional assistance was obtained from Central Workshops who supplied a sub-section which took over the fittings and Unditching Gear and "Gadgets" (small internal fittings etc)."

Page - 14 - says:

"... During this period (July - September 1918) Tanks continued to arrive from England in large numbers, consisting chiefly of Mark V* and Medium Mark A.

The Mark V* machines arrived in much better mechanical condition than the Mark V had been doing, the "Gadgets" were practically complete and they arrived fitted with Unditching Gear on special Railway Wagons with a well body, called "RECTANK" which allowed of the clearance of the British loading gauges."

Hope this helps.

Thomas

Centurion · Legend

Thomas
Indeed it does Sir.

You've confirmed a couple of theories

1. The strict British loading gauge restrictions did indeed restrict what could be done to tanks in Britain (they actually continued to be an issue in the next war being a major problem in WW2 in restricting the size of turret ring and therefore the gun fitted to British tanks which until about 1944 were seriously undergunned).

2. Central Workshops played a major role in fitting out tanks, often under pressure, which would in part explain inconsistencies between individual tanks.

One thing puzzles me, the Rectank wagon was available in time for later Mk IVs and Mk Vs so I'm wondering why it was only the Mk V*s that arrived correctly fitted out.

Thanks for your info

Centurion · Legend

Did a little more digging and found a photo of a Mk V* on a RECTANK1 leaving the Metropolitan works. Its all wrapped in tarpaulin but its clear that no unditching rails are fitted, moreover its passing through the loading gauge and one can see that had these been fitted it would not have passed! Given the extracts from the Central Workshop pages this is very puzzling. Does this mean that there was some intermediate point at which unditching rails were fitted before the tanks reached Central Workshops? Presumably in France were loading gauge restrictions were less?

1 RECTANKS first entered sevice in late 1917 so it seems strange that the first Central Workshops saw of them was in Sept 1918.

Thomas Buecheler · Captain

Hello!

The document "From Dwg 10121. ARRGT. OF UNDITCHING GEAR. MARK V." supplied by the Bovington Archive shows a symmetrical unditching gear.

From Chapter 2 of the "HISTORY and ORGANISATION OF CENTRAL WORKSHOPS and STORES, HEAVY BRANCH, MACHINE GUN CORPS (TANK CORPS), page 10:

"On the 17th April (1917), a Conference was held at the Central Workshops and the Mark V Machine was discussed for the first time and the General Arrangement Drawings were shown.

The discussion is not very clear in my mind, but, as far as I can remember, the Drawings were shown and we were told it would be the Mark V Tank and no alterations would be entertained.

About this period the Unditching Rail had come into being.

This Beam was accidentally discovered on the approach march for the Battle of ARRAS as many Tanks got ditched and it was found that the simplest way to extract them was by chaining a Sleeper across two tracks, the chains being those of the Buddicombe Spuds then in use.

Trials were carried out at Central Workshops of the different types and methods of fixing.

It was eventually decided to adopt the spar and fixing as used on all Mark IV Tanks at the present time...."

Regards

Thomas

eugene · Field Marshal

I noticed these "asymmetric rails" on the photo of Mk.V 9004 as well, I just thought they were bent, out of what were those rails built and how hard would it be for them to bend like that?

So if its an optical illusion, when you build a model would you just build them in a regular straight pattern?

thanks

Mark Hansen · Legend

The bend is on both rails, Eugene. One of the reasons they were bent on a Mk V was to allow clearance for the side openings on the rear cupola. The optical illusion is the "straight" rail.

Centurion · Legend

I'm still working on this but I enclose some of the photos I have cillected. There seem to be a variety of styles of rails (either that or there are an awful lot of optical illusions)

Mark Hansen · Legend

amtank.jpeg, laden tank.jpg, MKvloaded.jpg, and tank WW1-2.jpeg all show Mk IV's.

The Mk V* in mkvstarmale.jpeg shows why the rails are symmetrical. The supports are mirror copies left and right which they could not be if the rails were asymmetrical.

Notice also the position of the rails under the unditching beam. If the rails were asymmetrical, the unditching beam would have to hang further over one side of the tank than the other for the rails to pass under the same left and right hand points on the unditching beam.

Centurion · Legend

Mark Hansen wrote:

amtank.jpeg, laden tank.jpg, MKvloaded.jpg, and tank WW1-2.jpeg all show Mk IV's.
I am interested in unditching rails on all types so whats the problem?

The Mk V* in mkvstarmale.jpeg shows why the rails are symmetrical. The supports are mirror copies left and right which they could not be if the rails were asymmetrical.
No the supports are mirror copies because the rails are symetrical (at least in the horizontal) on this example. I'm not saying that ALL rails were aysmetrical just that some might be but I am saying that there appears to have been a variety of paterns. Hence the collection of examples , still growing. I did say I was working on it and have not even started to analyse - still collecting data.
Notice also the position of the rails under the unditching beam. If the rails were asymmetrical, the unditching beam would have to hang further over one side of the tank than the other for the rails to pass under the same left and right hand points on the unditching beam.
So? why do they have to pass under the same points?

Mark Hansen · Legend

I am interested in unditching rails on all types so whats the problem?
I have no problem with that, your original post mentioned MkV's and V*'s.

No the supports are mirror copies because the rails are symetrical (at least in the horizontal) on this example. I'm not saying that ALL rails were aysmetrical just that some might be but I am saying that there appears to have been a variety of paterns. Hence the collection of examples , still growing. I did say I was working on it and have not even started to analyse - still collecting data.
The supports are the same on all of the same type of tank. If the rails are asymmetrical, the supports have to vary.

So? why do they have to pass under the same points?
All unditching beams that are on the rails are placed evenly on the rails. Ergo, the rails pass under the same points left and right and, logically, the rails must be symmetrical.

If you wanted an answer that only went with your theory, why didn't you say so?

Centurion · Legend

Mark Hansen wrote:

If you wanted an answer that only went with your theory, why didn't you say so?

I wasn't looking for an answer but merely sharing the data collected so far with some initial observations (although all comments are welcome) This isn't a case of me defending a theory merely exploring it as this is a good way of us all learning during the process. To repeat myself

"I'm not saying that ALL rails were aysmetrical just that some might be ....... there seem to have been a variety of patterns. Hence the collection of examples , still growing. I did say I was working on it and have not even started to analyse - still collecting data."

The supports are the same on all of the same type of tank.

Can you prove this? Especially given the information supplied by Thomas that many rails and supporting fixtures were not fitted at the factory but some time after the tanks arived in France and often under pressure. If U do have definitive info this would be useful. Incidentally did those early Mk V*s produced in France have unditching rails? And did these have the same fittings as factory produced versions? Having once done an audit on REME's database that recorded the maintenance history of all contemporary British Army and RAF vehicles I'm all too aware of the potential difference between official policy and the expedients carried out by forward workshops and I'm sure the situation would have been the same (only more so) in WW1.

All unditching beams that are on the rails are placed evenly on the rails. Ergo, the rails pass under the same points left and right and, logically, the rails must be symmetrical.

Sorry I must be missing something. If the rails kink in different places (or kink on one side but take a more gradual angle on the other) this doesn't mean that they will be different distances from the centre line at all points only at some.

Finally can I request that any one interested in this thread please post any photos of rails and fittings (or any other relevant info). The sample data are still to few.

Roger Todd · Legend

Have a look at the photos attached to Bodlosh's 'Mark Vs in Estonia' thread, there are some very interesting views of Mark Vs with kinked rails, including some which I believe bear out the 'optical illusion' theory - though this is not to say that there were no asymmetrical rails, there may well have been and it's not for me to say otherwise, but I still think that some photos that appear to show asymmetrical rails do, in fact, depict symmetrically-kinked rails but the perspective conceals this.

BTW, if he visits this thread, thanks to Bodlosh for posting those images, cracking stuff there!

Centurion · Legend

Thanks Roger - If you look at the images I posted they already include the most relevant of the Estonian pictures that Bodlosh posted as well as Latvian images

Roger Todd · Legend

Oh aye, yeah, sorry - anyway, my point still stands.

Mark Hansen · Legend

The best examples of the differences in perspective in Bodlosh's Mark V's in Estonia thread are the ones labelled tankMkV_paalik_rae_01.jpg and Rae, P��lik, Waldaja for a comparison of Paalik, and unknown (one of them is Rae) (also in this thread) for a side by side shot of the difference in appearance caused by off angle filming. In the Paalik photos, Paalik appears to have a very distinct kink in the left rail (viewed from the rear) which all but disappears in the second shot.

The first Paalik photo has already been posted in this thread but the second had not and was a much needed comparison of the same tank taken from different angles.

As an example of what even a modern camera can do to perspective, my build photo (100_0977.jpg) in Group Build late entry has given my Mk II supply tank a bad case of "Does this make my butt look big?". It looks as if the whole rear end is much wider than the front. A reasonably good measurement gives 32.5mm +/- 0.5mm across the horns front and rear.

Mark Hansen · Legend

Four photos of the same tank taken on the same day at the same location. Mk V* 9649 has rails that appear to distort from one photo to the next.

What the correct chronological order for these photos is I can't quite figure out as yet.

Mark Hansen · Legend

Centurion wrote:

Can you prove this? Especially given the information supplied by Thomas that many rails and supporting fixtures were not fitted at the factory but some time after the tanks arived in France and often under pressure. If U do have definitive info this would be useful. Incidentally did those early Mk V*s produced in France have unditching rails? And did these have the same fittings as factory produced versions? Having once done an audit on REME's database that recorded the maintenance history of all contemporary British Army and RAF vehicles I'm all too aware of the potential difference between official policy and the expedients carried out by forward workshops and I'm sure the situation would have been the same (only more so) in WW1.

The proof is in the pictures. In the shots where the supports or the top of the tank is visible, the supports on a particular Mk of tank are the same.

Remember that written records can also be subject to error e.g. John Glanfield in "The Devil's Chariots", presumably quoting from the Lincolnshire Archives, stated that Mk I's & II's from Foster's used boilermakers pitch because that was what their boiler shop was used to. The photos of Foster's built machines tell a different story.

Thomas Buecheler also stated "The document "From Dwg 10121. ARRGT. OF UNDITCHING GEAR. MARK V." supplied by the Bovington Archive shows a symmetrical unditching gear." (My emphasis).

P.S.: The best way of confirming the asymmetrical hypothesis would be a photo of a tank from the right rear quarter showing a straighter left rail and a kinked right rail or from the left rear quarter showing a straighter right rail with a kinked left rail. Alternatively, a shot from directly behind showing either side rail straighter than the other.

-- Edited by Mark Hansen at 07:47, 2006-05-19

Centurion · Legend

Mark Hansen wrote:

The proof is in the pictures. In the shots where the supports or the top of the tank is visible, the supports on a particular Mk of tank are the same.

This in no way proves that all tanks of that mark had the same supports (unless you have photos of all tanks of that mk!). Most of our ideas tend to come from a limited number of photos of a relatively few tanks (given the number produced and deployed) which is why I'm trying to collect as many shots as possible before coming to any firm conclusions.

Unditching rails for Mk V and V*s almost certainly would have had to be fitted on arrival in France rather than at factory. I've found a photo of a Mk V* on a RECTANK with the loading gauge around it and it would not have passed with the rails fitted. I'll scan and post this PM

In looking at what I have so far found I can already see some questions re the rear 'turret' on Mk Vs and V*s and the way in which the chains from the unditching beam would be attached to the tracks. I have no theories or answers so I'll post these as a seperate thread.

Centurion · Legend

Just to add a minor note, the rear unditching rail brackets (those attached to the rear 'turret') on at least some Mk Vs were handed, that is to say the port sided one was not merely the same as the starboard turned through 180 degrees. They were not interchangable (at least a starboard bracket could not be used to replace a port one although the converse was not true). This was bcause the port bracket incorporated the exhaust pipe support (the exhaust had to be lifted to the top of the line of the side of the turret to allow the side flap to open) and therefore had two holes , one round (for the exhaust) and one vertical oval whilst the starboard bracket was completely open.