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Miniatures Adventure => The Second World War => Topic started by: JamesValentine on January 10, 2019, 03:27:26 PM

Title: M10 vs. M4 - why have both a TD and a tank?
Post by: JamesValentine on January 10, 2019, 03:27:26 PM
MOD EDIT:

I've split this topic to clear up the more practical posts from the sillyness (which is still okay, mind, just in a different thread now).

The OP asked about the purpose and rationale behind having both the M4 Sherman tank and M10 tank destroyer when they were broadly similar in armament and resource requirements.
Title: Re: Why did M10 exist???
Post by: Abbner Home on January 10, 2019, 03:42:57 PM
More knowledgeable people will surely pipe up, but...

The US Army at the time had a specific doctrine for what they called Tank Destroyers and those units were not intended to be tanks with a hot AT gun. They were intended to be dedicated anti-tank and thus would not need such frippery as "adequate front armor" or a "closed turret". They were meant for shoot and scoot at medium - long range and were teamed with recon jeeps and armored cars to help located enemy tanks to then destroy.  So the M-10 was the first TD designed to meet that doctrine and thus its existence.
Title: Re: Why did M10 exist???
Post by: jamesmanto on January 10, 2019, 04:27:47 PM
The open turret would make spotting and target acquisition easier.
Title: Re: Why did M10 exist???
Post by: Ultravanillasmurf on January 10, 2019, 05:05:39 PM
I suspect that the key is the difference in weight between the M2/3/6 75mm gun and the 3 inch M7 gun (plus the weight of the ammunition).

Does the quoted weights include the  M10's counterweight? Field expedients weighed up to three tonnes.
Title: Re: Why did M10 exist???
Post by: Abbner Home on January 10, 2019, 05:09:20 PM
I don't think any one is saying that what the Army did was brilliant or wise. Just what their reason was at the time for good or ill.
Title: Re: Why did M10 exist???
Post by: Arrigo on January 11, 2019, 12:44:29 PM
Abbner is broadly right.

The M10 and the follow on M18 and M36 were created to fill the requirement for a full tracked turreted tank destroyer. It was a reaction to the German blitzkrieg as seen in France. The underlining idea was that tanks would have been used for exploitation, and not to get bogged head on against German panzer units. Massed TD groups would have dealt with the panzers. To get these masses of TD they had to be a bit cheaper than full tanks, plus because they were supposed to be faster thank tanks and able to quickly acquire target, the open topped turret and less armour made sense.  The bolts were for add on armour to keep the pace with tank developments.

On paper it made sense in 1940-41, by 1943 when the masses of German panzers are nowhere to be seen... a bit less. But the TDs were McNair (chief, Army Ground Forces) pets so they still soldiered on. There is still an ongoing debate if they were just useless or performed a real service. Certainly they were cheaper, and in some case allowed larger guns to be deployed faster than in tanks. Also the M10 was a derivative of the M3, so it did not really hamper M4 production.

Title: Re: Why did M10 exist???
Post by: Cubs on January 11, 2019, 01:08:41 PM
British tank development shows how easily these cul-de-sacs can be made with (initially) good intentions, which are then carried on through short-term need over longer-term wisdom (perhaps a little harsh, hindsight makes a genius of us all), changing requirements on the battlefield and, most frustrating of all, contractural arm-locks, industrial inflexibility or personal pet projects. 
Title: Re: Why did M10 exist???
Post by: SpaceCudet on January 11, 2019, 04:48:15 PM
It wasn't just that the M10 would be the quickest way to get a better gun into the field, tank destroyers were a different branch of the army with their own requirements. It just happened that these turned out to be pretty similar to a tank's requirements.

Originally, (until someone was impressed by the performance of AT guns in Tunisia) the US were not going to have towed AT guns larger than the 37mm. The bigger guns were considered too difficult to manhandle into position especially as the plan was to being attacking pretty much all of the time. So, it was always the plan to have self propelled AT guns.

   
Title: Re: Why did M10 exist???
Post by: Ultravanillasmurf on January 11, 2019, 07:22:17 PM
Also the M10 was a derivative of the M3, so it did not really hamper M4 production.
I know it is only one source (and YMMV) but Zaloga in NVG57 page 6 states that the original T35 was based on an M4A2, and (page 8) that the Army was so desperate for tank destroyers that they had a higher priority than M4 tanks. There was concern that M4A2 chassis production would not be adequate so the M4A3 chassis was used to build the M10A1.

It might be that the M10 assembly line might have replaced M3 production (but that is speculation on my part).
Title: Re: Why did M10 exist???
Post by: Arrigo on January 12, 2019, 12:10:20 PM
I know it is only one source (and YMMV) but Zaloga in NVG57 page 6 states that the original T35 was based on an M4A2, and (page 8) that the Army was so desperate for tank destroyers that they had a higher priority than M4 tanks. There was concern that M4A2 chassis production would not be adequate so the M4A3 chassis was used to build the M10A1.

It might be that the M10 assembly line might have replaced M3 production (but that is speculation on my part).

Do you know I have Steve's visit card?  lol There is also a group picture in front of the main building at the RMAS with us standing together!  ;D

There are basically two sources on technical details of US AFV of WW2, Hunnicutt  and Zaloga; both agrees so it is not one source. Zaloga mentions the connection from the  M4A2 not only in the Osprey, but also in Armored Thunderbolt (that he claims, with sound judgment, to be his best book).  I think my comment was confusing because it looked like the M10 was built from M3.  To clarify, it did not replace M4A2 or M4A3 production at all. It was desgined with commonality with the M4A2 (M10) and A3(M10A1) and that made sense to reduce different parts floating in supply depots. The concept itself started as modification off the M3 (the awfully looking M9!), but then it was constantly redesigned to meet changes in requirements and different preferences.  Assembly started at Fisher, where M4A2 were also produced, probably to save on time.

It is also worth to note that while the US Army did not use the M4A2 (Marines and allies did), it did use the twin engined diesel M10. the A1 were either retained in the US for training or, later on, converted into M36.  So basically M10 while sharing a lot of commonalities with both the M3 and M4 (that, from an automotive point of view, were indeed similar until the A3E8), ended up having a production path of its own, based on a limited standard Sherman hull.
Title: Re: Why did M10 exist???
Post by: Ultravanillasmurf on January 12, 2019, 12:59:39 PM
Do you know I have Steve's visit card?  lol There is also a group picture in front of the main building at the RMAS with us standing together!  ;D
What with that and http://leadadventureforum.com/index.php?topic=114242.msg1429603#msg1429603 (http://leadadventureforum.com/index.php?topic=114242.msg1429603#msg1429603) it must be like one of Richard Castle's poker nights round at your place. ^__^

So to be clear, your comment
Also the M10 was a derivative of the M3, so it did not really hamper M4 production.
which I agree was unclear, does not represent my (and it appears your) interpretation of Zaloga's views on the development path of the M10 (in my case taken from the NVG57).

Cool.

Oh, I apologise for strange emoticons/emojis appearing in my text, the strange smiley is eight followed by close bracket. It is supposed to be the page reference for the quote but the forum renders it as an emoticon/emoji

The single source reference
I know it is only one source
related to my single source being the Zaloga New Vanguard title.


Title: Re: Why did M10 exist???
Post by: Arrigo on January 12, 2019, 04:52:49 PM
but because Zaloga NVG matched Hunnicutt (and the official sources too) it makes more than a single one  :)

Oh well people I met around... Heinz Frieser (Blitzkrieg Legend) sitting in front of me in a train; Having a lunch with Richard B. Frank (with me: that Richard B. Frank?  Heim; Do you have read some of my books?), chatting with a Royal Navy Admiral withour realizing he was the husband pf Princess Anne...  having Anthony Beevor's son as a student (in a war studies module), talking with Sir Robert Thompson's daughter (she was doing a PhD at the same time as me),  being introduced to Adrian Goldsworthy ('He  is Adrian'), discussinf the fine art of unguoing torpedo aiming with Paul Kennedy ('oh  so in the end it was just point and hope') well, I had my moments :) .


On the perverse side: one me and my supervisor (at the time professor Saki R. Dockrill) complaining a lot about 'Eating soup with a knife' and John Nagl, then leaving her office to go downstairs to get some stuff in the department office and then going to grab some food at the canteen and seeing him in the corridor... waiting he was out of sight and chuckling...  lol  of... having an argument with General Petraeus' mistress, without even knowing who she was...


Back to tanks...
Title: Re: Why did M10 exist???
Post by: Ultravanillasmurf on January 12, 2019, 06:04:43 PM
but because Zaloga NVG matched Hunnicutt (and the official sources too) it makes more than a single one  :)

I do not doubt that, however I had only the Osprey book, so it was my single source which contradicted my understanding of your statement about the M10 being based on the M3.

I did see the Queen Mother drive by while I sat on top of a World War One tank at Bovington forty years ago ^___^.
Title: Re: Why did M10 exist???
Post by: Ultravanillasmurf on January 12, 2019, 06:34:20 PM
Back to Mr Valentines's original question.

From Zaloga NVG57, the design originated as part of the underwear changing moment that was the Blitzkrieg.

The US Army concluded that they needed something and a whole bunch of designs was the result. Most of them made TOG look like cool kit (The M5 3 Inch GMC is described as "clap-trap" - see page 4).

Complaints about the designs led to (US) Ordnance recommending the design of a Tank Destroyer using the 3 inch gun from the M6 heavy tank fitted in a partial (frontal armour) turret on an M4A2. The approved T35 had an all round turret.

Experience in the Philippines December 1941 - January 1942 showed existing designs with vertical plates were vulnerable. This led to the T35E1 with the distinctive sloped armour.

The pilots were too heavy, so armour was reduced from one inch to 3/4 inch plate on the sides.

The final version was type standard as the M10 GMC. As there were concerns about M4A2 production not meeting requirements, a version using the M4A3 chassis was designed as the M10A1.

If you want to know more, I suggest Osprey's NVG57. It tells you all about the bizarre politics of the US Army of the time.



Title: Re: Why did M10 exist???
Post by: custosarmorum on January 12, 2019, 10:22:47 PM
For a thorough discussion of the U.S. development of Tank Destroyers, their doctrine, and employment, I would recommend Christopher Gabel's monograph on the subject, which is conveniently available online:

https://www.armyupress.army.mil/Portals/7/combat-studies-institute/csi-books/gabel2.pdf

Title: Re: Why did M10 exist???
Post by: Etranger on January 13, 2019, 01:23:52 AM
Why not look back to the original documents?
FM-18-5 FM 18-5: Organization and Tactics of Tank Destroyer Units
Tank Destroyer Field Manual, War Department, June 16, 1942
http://www.lonesentry.com/manuals/fm18-5-tank-destroyer/index.html
Title: Re: Why did M10 exist???
Post by: Ultravanillasmurf on January 13, 2019, 09:16:25 AM
For a thorough discussion of the U.S. development of Tank Destroyers, their doctrine, and employment, I would recommend Christopher Gabel's monograph on the subject, which is conveniently available online:

https://www.armyupress.army.mil/Portals/7/combat-studies-institute/csi-books/gabel2.pdf
Thanks for that.
Title: Re: Why did M10 exist???
Post by: MartinR on January 13, 2019, 09:41:37 AM
I'm a little late to the party on this one, but the M1 was essentially just a self propelled anti tank gun and that respect no different to the vast range of SP AT guns cobbled together by the Germans, Russians, Italians and to a lesser extent, the British.

What was unusual was US Tank Destroyer doctrine, which was rather more aggressive in the use of SP AT,  envisaging them actively seeking out enemy armour to destroy, rather than moving rapidly to set up nice reliable Pak fronts like the Germans, Russians and British did.

Using WW2 tech, this didn't work too well, but it works very well indeed if your SPAT weapons happen to be AT helicopters. When I'm not on my phone, I'll chip in a bit more.
Title: Re: Why did M10 exist???
Post by: Arrigo on January 15, 2019, 02:54:33 PM
Lots of names and terms I'm not familiar with. But an interesting read.

Out of curiosity could anyone do a quick Shop of the M10 turret on the M4?
It'd be interesting to see.
I did ask around on Facebook to see if a Rubicon turret fits on a M4. But other than figuring out I'd need to modify the turret ring most responses were about the M36B1 frustratingly

because it was done with the M36B1 and not with the M10. From a quick shot I would say it would not be a good idea
/
By the way James, I would say that your imagination is disconcerting. Are you sure you are not a relative of Igor Frankestein? (or was Frankestin?)  8)  o_o
Title: Re: Why did M10 exist???
Post by: Ultravanillasmurf on January 16, 2019, 04:52:43 PM
Out of curiosity could anyone do a quick Shop of the M10 turret on the M4?
It'd be interesting to see.
I did ask around on Facebook to see if a Rubicon turret fits on a M4. But other than figuring out I'd need to modify the turret ring most responses were about the M36B1 frustratingly

If you look at the instructions
http://forum.rubiconmodels.com/index.php?topic=407.0 (http://forum.rubiconmodels.com/index.php?topic=407.0)
You can see the M10 turret has the full (ish) 69 inch turret ring, whereas the M4 and M36 turret has the (same) reduced bayonet fitting rather than the 69 inch turret ring.

It is a bit irritating that no one does the Sherman with a scale(ish) turret ring, because it makes converting them to a Kangaroo difficult.

This of course means that a Sherman turret will fit on a Warlord Cromwell, but not the other way round (as opposed to real life where the Cromwell turret ring was smaller).
(https://2.bp.blogspot.com/-kk_hUxQO-go/Vwya3oNrVsI/AAAAAAAABXo/ezPLl2l5Mfkl7L8dme0BKCFHvR3Tls4oACLcB/s1600/shermwell2.png)

(https://4.bp.blogspot.com/-WqNDvJWf4Yc/Vwya3vO5_lI/AAAAAAAABXs/TDQ5oY0RNxA7H3aqzA6w30QZedJruDP5ACLcB/s1600/shermwell1.png)

Unfortunately I do not have the kit to hand (see Rubicon forum thread on metal figures).

However, if you do an image search for "t35 tank destroyer" you will see some of the M4A2 based prototype with the original turret.
Title: Re: Why did M10 exist???
Post by: Griefbringer on January 16, 2019, 05:48:28 PM
That Sherman turret on Cromwell hull looks quite stylish, but that boxy Cromwell turret on the sloped Sherman turret looks really awkward. And I am quite fond of the look of the regular Cromwells.

As for the Hello Kitty tanks, there are some scary designs out there - look for them at your own risk.
Title: Re: Why did M10 exist???
Post by: custosarmorum on January 21, 2019, 01:48:01 AM
Thanks for that.

Glad you found it of some interest.