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bsmart · Posted: Fri Mar 19, 2010 2:44 am Post subject: Re: Sherman Firefly

2) "They could ship locomotives why not heavier tanks

Planning for the entry into Europe began in 1942. At that time Shipping was a very critical issue. The 'Battle of the Atlantic' was still in the Desperate phase (remember the first shipment of Shermans that were sunk on their way to 8th Army in July of '42) Up until mid 43 it was a close call as to whether shipping was being lost faster than it could be replaced. That meant shipping space (and tonnage) would be critical. So both the 'Cube' (volume) and Weight had to be prioritized and balanced. It was decided in the various priority commities that Several 30 ton tanks were better than one or two 50 ton tanks. This was done early in the planning process. So priorities for the heavy tank (The M6) was reduced in priority since it was not expected to have shipping space, or a user driven demand. The pdesign plans for the Heavy tank were finalized in October 1940. I don't think the Tiger was even concieved at that time. At this time it was armed with a 3" gun and a coaxial 37mm. Later a turret with a 105mm gun (Not a howitzer a 50 caliber or so gun Shocked

) The other problem that came up with the heavy tank was reliability. The U.S. had some of the strictest reliability requirements of any country. This was at least partially derived from teh known need to support armies half way around the world. While German tanks fought within 1000 miles of the factory in almost any theater they were were deployed to American tanks had to move 1000 miles to get to their port of embarcation just to be laoded on a ship to begin their journey. I remember picking up somewhere that the M6 Heavy tank was able to run 1500 miles without maintenance but was still not considered reliable enough to be deployed. I don't think German heavy tanks ever reached that level of reliability. Because the priority of the heavy tank program had been reduced it was decided not to continue working to meet the reliability requirements. Initial production had been planned at 100 vehicles a month. There were 1354 Tiger I s built in about two years of production (Nov 42 Nov 44) so the U.S> was planning on building an equivilent number in one year.

As far as the fact they could ship locomotives. Locomotives were not being shipped in the volume that tanks were. Also some of the rail equipment was shipped in specialized vessels (Like the Seatrain Texas) that were equiped for it (70 ton cranes, tracks built in the decks, etc) and again locomotives were special priorities because they greatly reduced the number of trucks needed to run the logistics system.

I've also read that M26s could have been deployed a little earlier than they were. They were held up because the Bailey Bridges that had been stocked up fro the campaign would have needed modification kits to easily allow the wider Pershings to use them without a high probability of damage. The Pershings were withheld until most of the rivers had been crossed and the open terrain of Germany was in front of them

bsmart · Posted: Fri Mar 19, 2010 2:50 am Post subject: Re: Sherman Firefly

- Dontos

I usually don't get into these type discussions since my Sherman knowledge is lacking.

However, I do think that there is one 'exception'. Case in point is the M4A3E2. The earliest 'mention' to the idea is Feb 44, limited production in May/June/July 44, Shipment beginning in Sept 44, and in the hands of the Troops beginning in Sept 44. Now thats fast, even by todays standards......

BUT doesn't really prove anything except there is always one exception to any case......

It exactly proves that when there was a priority need that was recognized the system could respond

I'll shut up & try to learn somemore from this kniowledgable panel. A very deep discussion that is an excellent read.

Thanks
Don

Nah, join right in. I'm no 'expert' I just have tryed to read multiple sources, remember things and try to fairly evaluate them. (The I dig my heels in and fight like hell Wink

)

The more the merrier

bsmart · Posted: Fri Mar 19, 2010 3:21 am Post subject: Re: Sherman Firefly

3) In the meantime:
- The German army switched from the 75mm on the Pz IV to the even more deadly 75mm on the Pz 5
- The Russian army had changed from the T34/76 to the T34/85
- The British army had changed from Crusaders to Churchill. I know they classified their tanks different, however they tried to do something

Well The Pz V first appeared in mid 43 but the Pz IV remained the base vehicle in production for what another year?

The Soviets upgraded from the T34/76 to T34/85 - Similar to the change from teh 75mm Sherman to the. 76mm Sherman. Anyone who has taken one of tours at Aberdeen knows my feeling on the T34 and the Sherman. I fell they were the two best tanks of WWII. Each had it's advantages and disadvantages and both traded some 'superier' features for production feasability. Reading Loza's book (Commanding The Red Army's Shermans) was interesting he felt the Sherman was as good as the T34. It's qualities were different from the T34 but that did not negate the fact that he felt it was an effective weapon.

British Tanks - Well the Chucrchill did not replace the Crusader. The Crusader was a 'cruiser' tank and was replaced in production by Centaurs and Cromwells which were armed with 6 pdr and later 75mm guns. The Churchill was an Infantry tank and fell in the series of the Matilda II, and Valentine. The Valentine started life with a 2 pdr and the last ones had been upgraded to a 75mm. The Churchill started with a hull mounted 3" Howitzer and a turret mounted 2 pdr. That was repalced with a 6 pdr and later a 75 mm (The same as the Sherman) None of these tanks carried a better gun than the Sherman. In fact one problem with teh British tanks is they were all designed with smaller turret rings that could not be upgraded to large guns like the 17pdr. In that way the Sherman was actually better since it had been designed with a larger (69") turret ring that was capable of handling larger guns like 76mm, 17pdr, and even 90mm.

By the end of the war the British were starting to build tanks with 17pdr (The Black Prince based on a widened Churchill) 77mm (The Comet cruiser tank) or the first of the next generation (and one of the truely great tanks of all time) The Centurion.

Of course there were also the less than successful Covenanter and Cavalier. And again The Sherman picked up a lot of the slack.

And don't get me wrong I really like the Churchill. It had a great reputation for survivability, could climb hills better than most other tanks and was large enough that it was a great basis for specialist vehicles. But it was sllooww.

Michel_Krauss · Posted: Fri Mar 19, 2010 6:11 pm Post subject: Re: Sherman Firefly

- Doug_Kibbey

1. Development is not production, it takes quite a while to convert prototype models and adapt existing lines to mass production....and assumes the product is even ready

True, however when there is no development - there will be nothing there for production
If development is dropped to an minimum it will delay and everything that will follow after, will also delay

- bsmart

I think the Tiger didn't debut until Mid 43 (about the same time as the Panther) So until they came out in Mid 43 (not 42) There was no direct proof that the Sherman was outclassed.. Yes it could be expected and work was being done on larger tanks but there was no direct evidence

Small correction on this part
The first Tiger tank debut was mid 1942 with the s-Pz Abt 502 in Russian
In Africa the first Tigers appeared with the s-Pz Abt 501 in Tunisia in november 1942
So the Sherman was outclassed in 1942

Michel

Michel_Krauss · Posted: Fri Mar 19, 2010 6:38 pm Post subject: Re: Sherman Firefly

2) "They could ship locomotives why not heavier tanks

- bsmart

The pdesign plans for the Heavy tank were finalized in October 1940. I don't think the Tiger was even concieved at that time

Well first development for an AFV, which later turned into the Tiger, started as early as 1938
Back then it was still an 30 ton AFV, at the end of 1941 this became an 36ton AFV
The final developmentof the Tiger started in May 1942

Concerning the shipping distance, the points you mention are all true, only you are forgetting 1 thing
In Germany an big part of the 1000 miles back to the factory where bombed or the factory it self was bombed
That was an problem the US army did not have

So the shipping lanes may have been longer, they where also safer

- bsmart

I've also read that M26s could have been deployed a little earlier than they were. They were held up because the Bailey Bridges that had been stocked up fro the campaign would have needed modification kits to easily allow the wider Pershings to use them without a high probability of damage. The Pershings were withheld until most of the rivers had been crossed and the open terrain of Germany was in front of them

This wonders me that there had to be special modification to the bridge bacause of the M26

The British Churchill weight was only 1 ton less then the M26
Never heard of it that the British could not send the Churchill across an Bailey bridge, because it was to heavy

The British army had to travel to German across Belgium and The Netherlands
And if there is one location in Western Europe with an lot of rivers to cross, then it's Belgium and The Netherlands

Michel

Doug_Kibbey · Posted: Fri Mar 19, 2010 10:38 pm Post subject: Re: Sherman Firefly

- Michel_Krauss

2)
This wonders me that there had to be special modification to the bridge bacause of the M26

The British Churchill weight was only 1 ton less then the M26
Never heard of it that the British could not send the Churchill across an Bailey bridge, because it was to heavy
Michel

The Bailey Bridge was by no means the only bridging equipment used in the ETO (and they were not so readily available as "Kelly's Hero" might lead one to believe. At least as important were the pontoon and treadway bridges (built in varying degrees of complexity and capacity, depending on the conditions). Erecting any bridging under fire is never simple (though it certainly has been done).

Two sources to which you might want to refer to some of the difficulties are the chapter "Hell and High Water" in Michael Doubler's "Closing with the enemy" and the link below on the Rhine crossings.

140.194.76.129/publica.../c-7-5.pdf

There are many other sources on bridging information in WWII, if someone else cares to list them. I'm on the way out the door.

Michel_Krauss · Posted: Fri Mar 19, 2010 10:49 pm Post subject: Re: Sherman Firefly

Hi Doug,

thanks for the file, will read it

However the point of modifications still remains
The problems with bridging are not an problem for only the US army
All the Allies faced the same problem, because most of them used the same equipment

Strange thing by the way
If there is one piece of equipment connected to the US army it's the Bailey Bridge
However the construction of the bridge was developed in the UK

Michel

Doug_Kibbey · Posted: Sat Mar 20, 2010 12:51 am Post subject: Re: Sherman Firefly

- Michel_Krauss

Hi Doug,

However the point of modifications still remains
The problems with bridging are not an problem for only the US army
All the Allies faced the same problem, because most of them used the same equipment
Michel

Only the U.S. Army had to contend with transporting and supporting it's bridging equipment (as well as it's tanks) across the Atlantic Ocean. No other Allied or Axis power had to consider that, as has been already pointed out.

I'm having some difficulty following the point of your thesis, other than it seems a blanket condemnation of the U.S. for not producing what amounts to a Tiger equivalent in what you regard as a timely manner. Is that what you are trying to say, or is there something more that is not so readily apparent?

Anti-Tiger (all ~1,500 of them) roles seemed to have been adequately fulfilled by Allied artillery and CAS.

bsmart · Posted: Sat Mar 20, 2010 1:20 am Post subject: Re: Sherman Firefly

Let me try this again (The computer ate my first attempt Sad

)

I got sloppy when I specified Bailey Bridges. The U.S> and British had established 'loading gauges' for their family of bridging equipment. This established a range of vehicle widths (including wheel or track withs) that could safely and effecively use the bridges. When the M26 came along it was wider than the existing gauge. Although it could use some of the bridging equipment the chance of damaging the bridge or the tank was increased. There were modification kits being produced that modified the bridges to handle wider vehicles. These kits were not available in enough volume or throughout the commands in time to be available for the campaign through France and Belguim. SO it was decided not to push up the employment of the M26 until most of the rivers had been crossed.

The Churchill while as heavy as the M26 was narrower (This was the reason it couldn't me modified with the 17pdr) so fit within the standard loading gauge.

As far as the dates for the Tiiger I don't see the Nov 42 date when they were sent to Tunisia as the important date. I think the date when it was first encountered by the western allies would be a better date to use. I think that was spring of 43. Also with teh development dates. I saw the dates for the 30-35 ton tank when i went back to check something else for this discussion. But I think a 30-35 ton tank doesn't fit the role of a heavy tank. The M3 Lee and the M4 Sherman were in that class. So I think when the requirement was changed to something in the 45 ton class would be more appropriate. But I will concede that both armies saw the need for a heavy tank and started development.

About the distancesI'm not sure the sea lanes across the Atlantic were any less attacked than the rail lines out of Germany in the 41-43 era when the plans were being developed. I think the distances involved put the American army in a different mindset than the Germans. When German tanks need major maintenance or overhaul they were returned to well established and equiped depots and factories in the German industrial base. The Americans planning for a widely deployed army figured that once teh tanks were shipped overseas they were not coming back home until the war was over (if at all) Soany maintenance, upgrading or repair would be done by field depots without the advantages of large heavy industrial faclities. This caused them to be more demanding in reliability and maintenance requirements. This meant that tanks were not 'standardised' (Made available for general issue) until they meat high reliability standards, had extensive spares kits developed and mobile repair shops capable of supporting them were ready for deployment. So the teething problems that Tigers and Panthers had early in their careers would not have been accepted in the U.S. Army. Tanks in the 45 tone and heavier categories were pushing the capabilities of engines and transmissions. That was he primary issue that held up the American Heavy tank program. German heavy tanks continued to have mantenance issues throughout their lives. This was accepted by the german army. The U.S. army was not willing to do that.

C_Sherman · ***Power User*** Offline Joined: Jan 24, 2006 Posts: 590

Gee, invoke the ghost of the old board and look what happens!

Seems like I'm not the only one who remembers the discussions, too. (And we even got someone to mention 'shatter gap'...just like old times.)

There were two other delaying factors that may have been mentioned glancingly but not explored further: Organizational and industrial inertia.

By organizational inertia I mean that there was a good deal of resistance, within the US Army in the US, to changing the doctrine that led to the M4 Sherman's development. That was the "infantry support" doctrine that emphasized the HE capabilities of the tank, instead of the AT capabilities. There was a strong cadre in the War Department that believed in the doctrine, and took considerable convincing to change their minds. The introduction of the M10 TDs was to some extent an effort to augment the AT force without compromising the basic "infantry support" doctrine. In the end, enough evidence was presented that North Africa, then Italy, then the ETO were not exceptions to the doctrine, but rather showed an need for new doctrine. But this did not happen until it had influenced arms production schedules until around 1943.

Industrial inertia is simply the inherent resistance that any industry has to changes in production methods, materials and processes. In the instance of heavy manufacturing industries this inertia is considerable, and moreso when it is imperative not to interrupt production before or after a change. Changing a heavy manufacturing operation is more than just re-arranging the machinery and changing the drawings. Every single part must be changed simultaneously, and each part has a trail that leads through engineering, production, and logistics back to the shovel digging the iron ore out of the mine it is found in. Machine operators may need to be re-trained to use new production techniques, or just to understand the drawings and assembly sequences. And all of these need to come together within a day or two of the previous production line being stopped (at least under wartime production). It's a huge undertaking that happened simultaneously with the urgently needed production already underway, and planned to the smallest detail. It's not hard to imagine why there was a good deal of caution about making major changes to any tank production without some very convincing reasons!

So, my additional $0.02. Probably worth more if it was Canadian, but it's all I have in my pocket at the moment.

Chuck

Michel_Krauss · Posted: Sun Mar 21, 2010 11:47 am Post subject: Re: Sherman Firefly

Hi folks,

I would like to make an general request first: would you all be so nice to
1) drop the abbreviations or;
2) at least to explane it once what it means, when planning to use it more often?

My native language in not English and I have to search them all
The ETO was easy to find, only 36 abbreviations options
ETO European Theater Of Operations

However for CAS I have found about 200 abbreviations options
CAS Close Air support

Thanks,

Michel

Michel_Krauss · Posted: Sun Mar 21, 2010 2:11 pm Post subject: Re: Sherman Firefly

Let's continue with the discusion

Well the point is correct that all nations kept on developing new weapons, except for the US army

- The Germans developed new tanks, the known Pz III and IV (short barreled) where followed by the Pz IV (long barreled) and the Pz V

- The Russians developed the 76mm T34 into the 85mm T34 and all the other stuff they kept developing (ISU-152 / IS-2 / KW-85 / ISU-122 / etc)

- The British changed to an different classification for their main tank and also changed its weapons

The US army main tanks changed from 75mm to 76mm and it was not even an approvement

Concerning the artillery and the CAS
The artillery only has an change to knock-out an tank with an allmost direct hit
And because we are dicussing army doctrine at the moment, using artillery against tanks was also agianst army doctrine
The main job of the artillery was fire support, not shooting tanks
Shooting tanks was the job of the AT-folks, either towed or self propelled, who most of the time where not there when needed
In an matter of fact, the only ones who used artillery directly against tanks on an large scale where the Germans and the Russians

The CAS only had an change of knocking out tanks when it was fine weather
For example, the first day's of the Battle of the Bulge the CAS could not fly because of the bad weather
And if there was 1 moment in WW2 for the CAS, it was then

Concerning the Tiger tank, the first encounters where in Africa late 1942 and not mid 1943
The Britsh army started an crash production programm for the 17pdr AT in 1942 to have them send to Africa to stop the Tiger tanks there

Finally the Bailey bridge
The M26 was 3.5m width, the Bailey bridge road section width was 3.7m
What modifications where needed for the M26?
Also from what I understand about the gauges, it was more like "we have an piece of paper that say's it is not possible, so we cann't do it"

Michel

Kurt_Laughlin · ***Power User*** Offline Joined: Jan 24, 2006 Posts: 577

Regarding bridging and so forth, it was a real concern in the US Army.

The formal discussion and approval of Ordnance matters is documented in Ordnance Committee Meeting minutes (OCM). Many regarding tanks from 1944 on contain a non-concurrence from the Chief of the Corps of Engineers because of the effect that higher weights would have on the abilty of the Engineers to get the vehicles across streams with the equipment existing or in production.

For example, when the 76mm M4 was approved, the Engineers noted that previous agreements specified a 35 ton upper limit on tank weight. This was used to design the M2 treadway bridge: "The Chief of Engineers cannot design, test, and procure bridges to take care of these upward revisions in weight and get them immediately into the field for use. Though the steel treadway bridge M2 has just been standardized it is expected that they will not be available until the middle of this year." (10 Feb 44)

In the OCM regarding the M4A3E2 (2 Mar 44): "Inasmuch as the gross weight of the subject tank is 84,000 lbs., thus exceeding the maximum allowable weight of 35 tons by 14,000 lbs., the Chief of Engineers does not concur in the recommended action. " The same action also reiterated their concern with the recent authorization of 250 T26 tanks that weighed nearly the same as the M4A3E2 because "there is no f;oating bridge equipment available in the theaters to carry loads in excess of 35 tons . . . Furthermore, the new M2 steel treadway bridge when available, will have acapacity of only 40 tons in a 7 foot per second current."

As to having a "piece of paper" setting down limits; without any contrary evidence, that what you have to use to design things. You have to assume that everyone is working toward the same goals and that the requirements that are interchanged are real limits. You certainly don't want to be the guy who made something outside those paper limits when it is found that the limits are in fact correct when encountered in steel, stone, and brick!

It is not a simple matter to just bump weights up as needed. Everything that has been designed to or used with the previous limit has to be examined to find the weak link. If the design cannot handle it, it becomes an issue of determining what can be done to correct it. All designs have margins or safety factors built in, but they are there for a reason. The designer must account for things he suspects can happen doesn't know will happen. There may be limits (especially pre-computers) on what can be analyzed. There are inherent variabilities in construction and materials that must be considered. A very difficult and time consuming process.

Michel, have you read Armored Thunderbolt by Steve Zaloga? It has the most succint discussion of this whole issue.

KL

Michel_Krauss · Posted: Sun Mar 21, 2010 7:15 pm Post subject: Re: Sherman Firefly

- Kurt_Laughlin

Michel, have you read Armored Thunderbolt by Steve Zaloga

to be honest I did Mr. Green

And I'm an mechanical engineer for profession, so I know about the safety factor's Wink

The load bearing factor of the bridge is not the problem and has never been
The standard safety factor for steel construction is 1.5, however when used for the transport of or the protection of people it can be as high as 10

However discussion once in a while is also nice Twisted Evil

Michel

bsmart · Posted: Mon Mar 22, 2010 12:40 am Post subject: Re: Sherman Firefly

"The Germans developed new tanks, the known Pz III and IV (short barreled) where followed by the Pz IV (long barreled) and the Pz V"

I don't see much difference in the upgrading of the guns in the Pz III and Pz IV and the upgrading of the Sherman from the 75mm to the 76mm

"The Russians developed the 76mm T34 into the 85mm T34 and all the other stuff they kept developing (ISU-152 / IS-2 / KW-85 / ISU-122 / etc)"

And the difference with the M3-M4 Lee-Sherman which was used as the basis for the M7 (Priest), M10 GMC (Gun Motor Carriage), M12 GMC, M36 GMC, M40 GMC, M31, M32 and M74 Recovery Vehicles. And just for clarity the ISU-152, KV-85, IS-2, etc were out growths of the KV1 heavy tank developmant line not the T-34. But everyone used their basic vehicles as the basis for support vehicles

" The British changed to an different classification for their main tank and also changed its weapons"

This I don't understand. Towards the end of the war they did merge the Infantry and Cruiser tanks into a common 'Universal tank' But I don't see how this is seen as a complaint against the U.S. Army. The U.S. had standardised on on 'universal family of tanks much earlier. in The U.S. the M3/M5 light tank and the M4 medium tank was used both by Armored Divison units (where the British would have used cruiser tanks) and Independent tank battalions which were used to support Infantry units (Where the British would have used infantry tanks)

"The US army main tanks changed from 75mm to 76mm and it was not even an approvement"

I'll flat out disagree with this. As I mentioned above with the Pz III and Pz IV comparison. The upgrade from the 75mm to the 76mm was just as big of an improvement as the German upgrades or Soviet 76mm to 85mm upgrade. The Americans also upgraded the suspension. The U.S. had a very active development program. BUT they understood the need to maintain production while developing improved weapons. They also had to deal with competing priorities of several services and several theaters.

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