M3 Grant and M4 Sherman Family of Vehicles

[Jschmus]

This webpage claims that Australia had an unrealized (due to the surrender of Japan) plan to mount a Sentinel Mk.3 (Thunderbolt?) turret onto their M3 Medium......

Does anyone know if the 25-pounder was to replace the turreted 37mm gun or the hull-mounted 75mm?

The text specifically says "the fitting of an Australian Cruiser Tank Mark 3 turret mounting a 25 pounder gun". so presumably this would replace both guns.

[dy031101]

The text specifically says "the fitting of an Australian Cruiser Tank Mark 3 turret mounting a 25 pounder gun".

What I failed to phrase correctly is the question as to if and how the hull was to be modified...... 

[jcf]

According to this the M3 turret ring diameter was 54.5":
http://afvdb.50megs.com/usa/m3lee.html

... and according to this the Sentinel Mk.III turret ring diameter was 54":
http://en.wikipedia.org/wiki/Sentinel_tank

So most likely it was to be a straight turret swap and they would probably have removed the US 75
to save weight.

[dy031101]

The discussion leads me to another question- what's the turret ring size of the T-26?

I'm thinking of putting a reasonably powerful anti-tank gun in the sponson mount...... and, in the event of that gun being deficient in the high-explosive department, use a 45mm gun to compensate......  

[rickshaw]

A straight turret swap for the M3 would place the turret unacceptably high.  It would cause problems with concealment and of course with balance, placing the centre of gravity unacceptably high.

[Jacques Deguerre]

Okay...... still, is the Pershing turret tougher and/or roomier than the T23 turret?

Tougher, yes but actual crew space is "kinda sorta" similar. Please note that I don't mean raw interior volume but usable "working space".

One thing that I have seen mentioned here, although I might well have missed it, is the practicality of some of these proposed turret swaps. Most "Shermanaholics" are aware of the proposal to mount the M26 turret with 90 mm gun to the hull of an M4A3. You've probably seen the well-known line drawings in Hunnicutt's Sherman and possibly even the known photos of the actual test conversion. (Apologies for exceeding 700 pixels with this image.)


(EDIT: A bit of a "D'oh" moment when I realized that the test vehicle in the photo is a late production M4 rather than an M4A3. I believe that the proposed "production" version was meant to be an "A3" with HVSS, however.)

The basic story for why this conversion was never carried out for operational use is that the Pershing was simply a superior tank to the Sherman and by the time sufficient quantities of the M26 turret would have been available, so were sufficient quantities of the entire tank! It's technically feasible to mix and match a number of US turrets and hulls, since the M4 family (including the M10 and M36 TDs), the M18 Hellcat TD and the M26 Pershing, not mention a number of experimental, limited production vehicles, used the more-or-less US standard 69 inch turret ring. What gets overlooked is the relative weight and size of the turrets and hulls. A big problem with the M26 turret on the M4 hull is that it made the resulting vehicle considerably more heavy over all, as well as considerably more top heavy with a higher and much less stable center of gravity. Although this bit of information seems to get over-looked, the top heavy and high center of gravity problem was also an issue with Shermans equipped with the T23 76 mm gun turret and the problem was greatly exaggerated with the experimental M26/M4A3 combo. Some relief could have been found in using the HVSS for production vehicles, as well as modifying the transmission in manner similar to the E2 "Jumbo" Sherman. However, the better solution was to fit the turret to a lower, longer and wider hull and, as we know, they already had that.
FWIW, I think the M26/M4A3E8 90 mm combo is pretty darn cool looking, issues of strict practicality aside. Also, I recall reading somewhere that the T23 turret could technically be adapted to carry the M3 90 mm gun. Whether or not this is true, I have no idea but it might make for a cool, alternate take on a 90 mm gun Sherman.

[dy031101]

Also, I recall reading somewhere that the T23 turret could technically be adapted to carry the M3 90 mm gun. Whether or not this is true, I have no idea but it might make for a cool, alternate take on a 90 mm gun Sherman.

Might be along the line of how the Israeli M50 Sherman was made possible, extending the mantlet forward?

[GTX]

How about some captured M3s or M4s rearmed with German 75mm or even 88mm guns?

Regards,

Greg

[dy031101]

How about some captured M3s or M4s rearmed with German 75mm or even 88mm guns?

According to this website, Schmalturm armed with a KwK-43 gun has a turret ring diametre of 1750mm...... perhaps they can extend the mantlet forward (à la the later Sherman M-50) and weld an armoured box at the Sherman turret rear to allow for recoil space if required?

A M3 might have a better chance with a 75mm gun.  Unless they want to try a German execution of the SU-76i concept, I suppose......

[Logan Hartke]

I really don't see the 88mm happening in the Sherman's turret.  I'm not saying you physically couldn't.  I'm certain that you could stuff at least the 8.8cm KwK 36 in the T23 turret, possibly even the KwK 43, but I don't think either would be a comfortable fit, or worth the effort involved.  If they fit the KwK 36 in the T-34-85 turret, they could likely fit it in the T23 turret.  I've read that Chrysler said they could put the 90mm in the T23 turret and--while heavily modified--the Israelis used the same turret for the low-pressure 105mm.



The 7.5cm KwK 42 is another matter entirely.  It had similar performance, dimensions, and recoil to the 17 pdr.  The shells were also of a similar size.  The 17pdr and the KwK 42-derived CN-75-50 were both squeezed into the standard M4 Sherman 75mm turret, so I don't think it's unreasonable to think the 7.5cm KwK 42 could have been.  The radio would need to be removed from the rear of the turret, and the handling of the rounds would be awkward, but those were both accepted in the other conversions.  Likewise, the 75mm KwK 42 certainly would have fit into the larger T23 turret.

A modification that I think would be neat would be a converted M3 Lee/Grant somewhat like the T40/M9 Gun Motor Carriage.  The Germans capture an M3 Lee or Grant in North Africa or on the Russian front, remove the turret and insert an 8.8cm FlaK gun where the 3-inch gun exists on the T40/M9.



I think another version that would look neat and work well is a Jagdpanzer conversion with a built-up superstructure and a 7.5cm PaK 42, like the Jagdpanzer IV/70 (Alkett).  You could leave the entire engine deck alone, just continue the glacis up.





http://beute.narod.ru/Beutepanzer/us/M4_sherman/su/soviet.htm

Cheers,

Logan

[Weaver]

Apologies if this has been discussed before - havn't got time to trawl the whole thread....

The M3 Lee owed it's existance to the fact that a 75mm armed tank was needed quickly and it was judged that it would take too long to design and build a new turret to take one. The principle reason for this delay was the size of the casting needed, which meant new production facilities etc... Now then, the Sherman hull was originally cast too, but a welded flat-panel hull was introduced very early to avoid the bottleneck caused by the limited number of casting facilities that could handle something of that size. So my suggestion is: why not get Shermans into service sooner by adopting a welded turret, similar to a scaled-up late M3 Stuart turret?

[Weaver]

Here's another thought, and one that you could probably use to mess with a JMN head or two: put a Type-61 turret on a Sherman.

What's a Type-61? http://en.wikipedia.org/wiki/Type_61

The Type-61 is usually dismissed as a "Japanese copy of an M-47", but this is clearly rubbish: it's 10 tons lighter, has half the armour and almost none of it's shapes are really the same. The only real similarities are that it has a HUGE cast turret bustle and a 90mm gun with a T-shaped muzzle brake. I've got the exquisite little Fujimi kit of the Type-61 in 1/76th, and a couple of things strike me:

1. The turret is remarkably small.

2. The turret shape is NOT the M-47 "mushroom" shape with heavy undercuts, but is more like a Sherman's "dome" with a big bustle. Actually, it mostly resembles an M-36 Jackson turret with a Sherman roof.

Now what I don't have is a 1/76th Sherman to compare it to, but I'd take a reasonable bet that it fits, and looks okay, particularly if you dump the distinctive Japanese cupola.

[dy031101]

Stoolslinger's Texan tank project makes me wonder about the possibility of something more "modest"- can the Lee or at least Grant turret take a 6-pounder?

(That as an alternative to upgunning the sponson while keeping the 37mm with canister rounds......)

[Joe C-P]

Stoolslinger's Texan tank project makes me wonder about the possibility of something more "modest"- can the Lee or at least Grant turret take a 6-pounder?

(That as an alternative to upgunning the sponson while keeping the 37mm with canister rounds......)

In the world of What-if, many things are possible:

[dy031101]

In the world of What-if, many things are possible...

Hum...... it brings up another question: with a turret ring of 138cm, can I safely assume that all efforts to put a bigger gun into the turret risks displacing its loader?