discussion Churchill SBG Bridgelayer

[Guest]

Bit of nostalgia modelling, I first built the bridgelayer back in 1980, when the Tamiya Churchill was just a baby, so armed with one kit, loads of 1/16th thick black plasticard (you took what you could get back then) and plans for a 1/76 scale AVRE I set about the build. Rebuilt the turret, scratch built the rest except for the hull and running gear.
Fast forward to today.
I started this build some time ago but using the AFV Club AVRE Mk.IV version, and as with a lot of our models along came something new, I had already done the girl and 'boy' racer stuff so it had to be another model and/or work that sidelined the build.
So it has now resurfaced and is in build mode, with today work starting on the bridge itself, and as you can see from the last photo it is going to take a couple of days just to get the angle strips in place.
Cheers,
MikeC.
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[grumpa]

Great subject, and dedication to scratch building!
Am gonna watch this one :thumb2:

Jim

 

[Jim R]

Hi Mike
That looks just so neat and sorted. great stuff.
Jim

 

[Guest]

Hi Mike is this the bridge you are building if it is this might help if not sorry.

Tank Bridge, Small Box Girder

Tank Bridge Small Box Girder or SBG Assault Bridge. Introduced specifically for D Day and the 79th Armoured Division it was designed to support a Class 40 load over a 30 foot span, or more specifically a 12 foot high sea wall.

The bridge itself consisted of 4 Small Box Girder hornbeam sections connected together to form a twin trackway bridge, connected with crossbeams.
Churchill AVRE with Small Box Girder Bridge

Churchill AVRE with Small Box Girder Bridge
Unlike the Number 1 and Number 2, it was carried by a standard Armoured Vehicle Royal Engineers (AVRE), not a specialised bridgelayer and thus the carrying vehicle was able to be used in other engineering roles once the bridge had been detached.

The sequence of operation on a sea wall is shown below, including using a fascine to cushion the fall!

Churchill Assault Vehicle Royal Engineers (AVRE) SBG Bridge

A Mark II variant introduced a more sophisticated launching mechanism that provided for a more controlled release.

The bridges were carried on a small bogey trailer towed behind the tank and attached to the front prior to use.
Armoured Ramp Carrier (ARK)
The Armoured Ramp Carrier or ARK was used for crossing small gaps and used in a number of variants. At its simplest, an ARK was a tank with its turret removed and ramps fitted to the top of the superstructure and at either end of the hull.
The vehicle would be driven into the gap, deploy its ramps and other vehicles simply driven over the top of it. The original ARK’s were designed to enable other tanks to climb sea walls on the beach defences on D Day although it is not certain if any were actually used.
ARK Mark I, used in the D Day landings primarily for traversing the sea walls and defences it had a 2 foot wide wooden trackway with short ramps and about 50 were manufactured.

Pete.

 

[Guest]

Here’s one that’s not gone quite right:

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And what one looks like if you leave it out under those conditions for a year or so:

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(Different tank, but only at most a few dozen meters away from the other one.)

 

[Steve Jones]

Mike

This should be fun! Rather you than me. I wish you all the best and will follow on avidly taking notes

Steve

 

[Guest]

Pete,
Many thanks for the photo's and information. That is the bridge that will be built. It is basically a re-incarnation of my first model which vanished some time ago and so I thought it time to get building a new(er) model.
Jakko,
Again thanks for the photo's. I think the top one was taken on the morning following the storm that hit the beaches.
Steve,
It is not as bad as it looks, it is just the repetition that gets you, but thankfully I am almost over that stage.:flushed:.
Cheers,
Mike.

 

[Guest]

Jakko,
Again thanks for the photo's. I think the top one was taken on the morning following the storm that hit the beaches.

Um, no?

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The one on its side is the same tank, after being battered by the sea for longer. The location is:

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That photo was taken from the top of one of the caissons. The rolled-over AVRE is just out of shot to the right but the SBG bridge can be seen at the edge of the photo.

 

[Guest]

Jakko,
Many thanks for the photos and explanations of the locations.
Cheers, Mike.

 

[Guest]

Update....
Series of photos showing the main construction of the bridge sections all that is to be added are the smaller details and the inner cross plates as the one at the front.
Cheers, Mike.
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[Mickc1440]

That's some very nice scratchery Mike.

 

[Guest]

That’s looking pretty impressive. Mind if I ask what you’re using as references? Some years ago I built most of a 3D model of an SBG to have it 3D-printed in 1/72 scale, but couldn’t really find sufficient details on the ends of the bridge, so never finished it.

 

[Guest]

Jakko,
Those are nice renderings. I will sort out the end dimensions and sketches. I know for a fact that in 1/35 scale from the end of the treadway it is 11mm to the end of the narrow end section (if that makes sense) which is the part that the end beams are sitting on and the width if the lattice work frame. The drawings i have worked from in the past are the G.W. Futter 1/76 scale that appeared in the early editions of Military Modelling magazine and led to a now defunct book called "The Funnies". And that is where most of my original reference came from, since then we have been given the internet and that has helped a lot, but sadly not in the case of the bridges. If you would like copies of the Futter drawings, please pm your email and I will scan and send them to you.
Cheers, Mike.

 

[Peter Gillson]

Some excellent scratchbuilding - you are a braver man than I taking on tbis in 1/35. I am enjoying followign and seeing each stage

 

[Guest]

The drawings i have worked from in the past are the G.W. Futter 1/76 scale that appeared in the early editions of Military Modelling magazine and led to a now defunct book called "The Funnies".

I have that book, and unfortunately the bridge in the drawings in it is somewhat inaccurate, especially the width of the girders My 3D model is actually based mostly on the Matchbox 1/76th scale one, which seems to be more accurate than Mr. Futter’s drawings, when I compared it to photos I found online and in the same book.

 

[Guest]

Jakko,
The Matchbox/Revell version is an innacurate version. It got slated when first released as the Matchbox offering and it looks as if things have still not changed. The Matchbox/Revell Churchill alone is of a much later mark and never saw service as depicted by the kit as being on the beaches on D-Day. And if as you say you have based your measurements on that kit, I would be very sceptical of what you have. I used the Futter drawings on my original build and found them to be 90% correct, and as there are no other drawings available I would accept these as being correct. Bearing in mind the date of the drawings (1971) I would say that these are the ones to use as it appears there are no others. I have seen the self same drawings offered for download and when they are downloaded they are not to scale this is due to the computer. I have also had a chance to measure up the ResiCast version, but have been unable to obtain a copy of their drawings. So it comes down choice. When I built my original there was a small correction factor due to not having a 1/35 scale rule, and the accuracy is I admit not 100% but then again neither are all of the models produced. But when I come across this type of discrepancy I look at it this way, if it looks like a horse, then it is a horse.
Cheers, Mike.

 

[Guest]

Peter,
Pleased to have you along.
Cheers, Mike.

 

[Guest]

The Matchbox/Revell version is an innacurate version.

The tank is, yes.

And if as you say you have based your measurements on that kit, I would be very sceptical of what you have. I used the Futter drawings on my original build and found them to be 90% correct, and as there are no other drawings available I would accept these as being correct.

I’m not sure now what made me reach the conclusion that the Matchbox parts were better than the drawings, since it’s been a few years since I looked into it, but comparing Futter’s drawings to photographs left me with the definite feeling that the girders as he drew them are too wide.

I have seen the self same drawings offered for download and when they are downloaded they are not to scale this is due to the computer.

At least I don’t have that problem, as I’ve got a genuine, original, near-mint copy of the book. (Thanks to a local AFV enthusiast dying about ten years ago and his collection of 1960s–’80s books ending up in a second-hand book store I frequent. I wish I’d known him other than from his address stamp.)

when I come across this type of discrepancy I look at it this way, if it looks like a horse, then it is a horse.

That was my problem with Futter’s drawings, I think. But I can’t find my copy of the book right now (it’s probably in my hobby room) to compare and see if I can point to the problems I saw a few years ago.

 

[Guest]

Jakko,
Yes I agree with you. And the discrepancy is probably on the underside of the bridge. From some angles to underside looks as though it reaches across as in your rendering, but I am looking at two photos one of which is the first in the series you posted. There the bridge structure looks to be full width as in how it looks in the above shot of your rendering. But in the photo I am looking at which is 3/4 front view you can actually see that the structure is much narrower, as in my build today. BUT! I also have another view of just the bridge and it looks at first view as if the structure is full width untill you look carefully and you can see the other side quite clearly. And one more photo again 3/4 front, and here you can clearly see the bridge underside as depicted in my build, but wrong on the Futter drawings. The trackways were added in two different ways, one as per Futters/your rendering and the other as per my build. These observations were taken from 'Vanguard of Victory' by David Fletcher. I will scan the photo's and put them on the site tomorrow, it will give me something to do other than watch the liquid cement evaporate. Keep hold of the book it is a collectors item. And as for the Matchbox kit, it was again the only one available at the time and did the job when at the time we did not have the resources we do today for research.
Talk to you later Jakko, in this heat the dogs have to be out at about 05.00, so it's bedtime.
Cheers, Mike.

 

[Guest]

Yes I agree with you. And the discrepancy is probably on the underside of the bridge.

I’ve found the book now — it was in a pile behind me all along

In the drawing on page 35, Futter has the girder as being almost the same width as the bridge deck, but in photos (including the one on page 37) you can clearly see it’s about a third or so that width. Since you’re also building it much narrower than the deck, I think you’ve reached the same conclusion :smiling3: The Matchbox designers must also have noticed this (assuming they used Futter’s drawings at all, of course), because the bridge from their AVRE kit similarly has a girder much narrower than the deck.

Keep hold of the book it is a collectors item.

I wasn’t planning on giving it up, no :smiling3: