Interesting Sherman facts/myths (WiP)

[Pinky]

I am not sure how fair that is, the Americans had access to the British experiences and still managed to repeat a number of their mistakes.

Tank design is slightly odd as Britain needed as many tanks as it could get after Dunkirk, so new designs were left on the back burner in preference to existing designs - that can be the only reason for the production of 1.7k Covenanter tanks (only one of which was lost to enemy action - by a bomb near Canterbury).

I was talking more about the use of armour than tank design.  The British struggled for most of the desert war to coordinate armour and infantry, and even with massive numerical superiority at Alamein they did not demonstrate any real flair - it was basically just Montgomery's 'crumbling' approach, which involved wearing down the defences by attrition.  Then they had to re-learn it all in Normandy, and interestingly it was the less experienced formations which seemed to pick it up better than the veterans.  The Americans did watch the British, and learned some lessons, but of course had to learn most of it the hard way.  But if you look at how quickly they rebounded from the disaster at Kasserine, there's a sense that they had more of an affinity with mechanised warfare than the British.  The breakout from Normandy is another good example.  While the Americans tend to take far too much credit for this, and fail to acknowledge that the British took on most of the weight of the Panzer divisions, they still showed considerable flair. And by late 1944 the best US armoured units were very effective combined arms formations.

When it came to tank design, the British were plagued by outdated doctrines, competing demands and a strange lack of urgency.  Some of their better designs (like the Firefly) seem to have been a result of inspired amateurism rather than any kind of rigorous design process.  Despite being able to design and produce first class aircraft, artillery, trucks and even armoured cars, their tanks were mediocre at best, and often simply rubbish.  David Fletcher is particularly good at describing the weirdness that went on when it came to British tank design.       

The UK faced many logistics problems such as the fact that the country is dotted with low railroad tunnels and rail companies lacked appropriate flatbed carriages to move tanks from the factories.  The US sent large numbers of carriages to remedy this problem allowing the British to make large scale transport much easier.

The constraints of transporting tanks by train on the UK rail network are often cited as the reason why British tanks had turret rings which did not allow the mounting of a bigger gun.  I've never been entirely convinced.

UK industry was actually better organised than German industry, and produced more tanks than the Germans did overall. 

[ultravanillasmurf]

The constraints of transporting tanks by train on the UK rail network are often cited as the reason why British tanks had turret rings which did not allow the mounting of a bigger gun.  I've never been entirely convinced.

My working hypothesis (i.e. I have not actually researched it, just looked at examples and made stuff up) is that the limitation on suitable guns is that for a "Tank" at some point in the elevation of the gun a line passing along the barrel and breech will contact the turret ring, and gun needs to be mounted so that at maximum recoil the end of the breech and any equipment and fittings attached to the breech do not contact the turret ring.

For non tanks, it is acceptable to have the gun recoil entirely within the turret. leading to the common silhouette of the Challenger, Bishop and KV-2.

For tanks, you could mount the gun further forward, but that leads to issues of balance requiring counterweights on the barrel (leading to barrel droop affecting accuracy) and on the turret see the M10.

British tanks generally have the turret ring between the side plates of the hull and have a turret basket with rotating floor (I am looking at models of the Cromwell, Crusader and to some extent Matilda).

For a British tank the railway loading gauge limits the width of the tank, that width being twice the track width plus suspension, the hull side plates and the turret ring plus all the required gaps allowing movement etc.

The Sherman is a different (taller) shape due to the front drive sprocket and the requirement that the drive shaft has to pass beneath the turret basket.

Though the Sherman has a narrower hull between the tracks, there is a large amount of space above the tracks (the sponsons)  that is the full width of the vehicle which would allow a larger turret ring, at maximum elevation the recoil path is within the wider space. My assumption is that the turret basket is tapered (yes I am guessing).


This is a picture borrowed from the Shaddock site, my assumption is that it is copyright free.

This makes the turret ring about my estimated size of the Rubicon M10 turret ring.

Of course not all manufacturers of kits use the true turret ring diameter, here is a link to two pictures of a Sherman and Cromwell hull with their turrets swapped, the Cromwell model's turret ring is actually larger: http://ultravanillasmurf.blogspot.co.uk/2016/04/shermwell-1-and-shermwell-2-pictures.html

I wish they would, as it would make some conversions (Kangaroos for example) easier.

Other opinions are available ^___^.

[Pinky]

So the real issue with British tanks was that they insisted on putting the turret ring between the tracks, and not above it?  That makes sense - I wonder why they felt so constrained. 

[ultravanillasmurf]

My guess is that the designers want to make the tanks as low as possible, the armour plate required to raise the turret higher adding to the weight. Plus it increases the height of the tank making it easier to hit.

Looking at the Sherman picture, there must be something to support the turret, to transfer the recoil from the turret to the body (ever seen the video of an Iowa class battleship firing it's guns?). I assume there is a ball or roller bearing arrangement around the circumference of the turret ring.

[ripley]

If you have a turret basket , it has to fit between the hull sides as they extend 4 or 5 ft down into the hull and , on the Sherman clear the drive shaft  . The T-34 and JS tanks had no basket , just crew seats hanging on the turret race ( ammo in bins on the floor ) hence the turret could be wider than the lower hull . The JS 2 shows this best IMO

[Pinky]

The Sherman's turret basket sat level with the top of the lower hull (i.e. the sponson floors), with an 'insert' below it.  It was largely removed in the 'wet' stowage configuration.  Presumably, if the Ford engine had been available when it was designed, they could have lowered the profile significantly (imagine what that would have looked like!).  Most of the recoil was absorbed by the gun mount (but if you've seen film of a Sherman firing, you can see that it still rocked on its tracks). 

I don't know why the British seem to have felt that the turret ring shouldn't overhang the tracks.  They achieved a low profile on tanks like the Valentine and Crusader, but ended up with undergunned tanks.

[ultravanillasmurf]

Presumably, if the Ford engine had been available when it was designed, they could have lowered the profile significantly (imagine what that would have looked like!).

I suspect it would look like a T23:

From the Shaddock site, 76mm turret.

[Pinky]

Good spot.  You can see the beginnings of the M47 hull around the engine deck.

[ultravanillasmurf]

@Ripley, looking at some line drawings (Osprey Modelling T34/76 and T34/85), the T34/76 appears to have the outer part of the turret within the line of the lower hull. The T34/85 does appear to be outside the lower hull - some drawings show the top deck of the hull extended outwards around the circumference of the turret base, but I cannot find a picture showing the turret ring at a good angle. The hull design would allow a similar arrangement to the Sherman discussed previously.

The cutaway drawing in the T34/85 New Vanguard book notes a counterweight on the breech.

I have misfiled my only Josef Stalin tank book.

@Pinky, I think only the walls of the basket were removed for better access and to offer the hull crew an escape route through the turret.

[ultravanillasmurf]

Good spot.  You can see the beginnings of the M47 hull around the engine deck.

The T20 series also included torsion bar examples, did the M46-47 have torsion bar suspension?

[ultravanillasmurf]

On the Other Company's M4 there are armour plates to protect the direct vision hoods.

I have found no pictures of British M4s fitted with the plates, but a couple of examples showing exposed direct vision blocks. There is a photograph of a line of tanks with side and front plates that are described as having been upgraded by the British for the US Army because the front right side plate is welded over part of the star.

Did British tanks have the plates on the hoods?

[Pinky]

@Pinky, I think only the walls of the basket were removed for better access and to offer the hull crew an escape route through the turret.

Most of the floor of the turret basket was removed as well, so that the loader could access the ammo bins that had been relocated to the lower hull with the introduction of 'wet' stowage.  The loader walked on the top of the ammo stowage when the turret was rotated.  There was still a partial floor under the gunner and commander.

The T20 series also included torsion bar examples, did the M46-47 have torsion bar suspension?

Yes, they did.

[Pinky]

Did British tanks have the plates on the hoods?

The Warlord M4 is a mid production vehicle, without direct vision ports.  The armour plates on the 'hoods' were introduced at the same time as the other applique armour panels.  They were sometimes attached over direction vision ports, but weren't specifically intended to blank them off.  British M4s had these plates (and they were modified for the Firefly version).

[ultravanillasmurf]

I vaguely remembered there being what I had assumed to be a representation of the DV block on the front of the hood. All four of my completed ones have the plates glued in place so I cannot check.

Baldwin apparently only built M4s with DV hoods.

The British Tanks in Normandy book has a number of pictures of Shermans with DV block exposed.

Here is the picture of the US Army tanks with the appliqué plate over the recognition star:

[ripley]

Originals Sherman had a direct vision slot covered by an armored panel . Also had a forward view periscope in front of the driver / MG hatch and a rotating periscope on the hatch covers . Periscopes easily removed if damaged or if using vision slot , it was in the way  . IRC , they found shell splinters would penetrate slot even when closed ( same reason Panther D lost driver's visor ), so 1st , they welded the slot cover , 2nd , added the extra plates in front of driver / MG  ( same time as 3 side armor plates ?" ) . Then they just cast the driver / MG  hood piece without a vision slot , these pieces were pre cast and welded on the  M4 type square  hull .   ( Same kind of thing with pistol port on turret , - 1st welded closed , then not even in the casting , but then they put it back  )  IRC the T-23 tank had the same turret race as the Sherman , they changed the gun mount , it was further forward , hence the bulging turret rear as counter weight . So it was added to Shermans  and that's why some pictures mention " M4A3 76mm ( T-23 turret ) And yes after a few  revisions the hull became the M-26  . Lots of one off US  concept / proto type  tanks like this in the Brit & US Tanks of WW2 book .