IS-2: performance, variants, cost, units.

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Art
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Re: IS-2: performance, variants, cost, units.

Post by Art » 07 Jan 2019 12:02

Art wrote:
21 Nov 2017 16:50
In a report submitted on 7 July 1944 technical officer of the 5 GTA noted that the army had to make marches on marshy and forested terrain, partly with sandy soil. "On those difficult roads heavy tanks and self-propelled guns of the 14 Guards Tank Regiment and 376 Guards Self-Propelled Regiment completely expended their maintenance resource and 70-80% of self-propelled guns and KV-2 (sic!) tanks are now in need of medium repair".
https://pamyat-naroda.ru/documents/view/?id=154006035
Some factory defects were discovered such as a flywheel having a faulty binding to a crankshaft or planetary steering mechanism's tendency to break down due to dust and sand. Special commissions from the Red Army's Tank Directorate and Commissariat for Tank Industry were called to investigate them.
Another document indicating that IS reliability problems were not an isolated incident:
https://pamyat-naroda.ru/documents/view/?id=153108937
An order of the Marshall Fedorenko from 27 July 1944 stated that in the first half of July the 1 Baltic Front had 46 heavy tanks and SP gun broken down due to technical factors. The reasons were said to be faulty maintenance and operations of vehicles: the air filters were not correctly assembled and installed and were not cleaned with sufficient periodicity, nonstandard oil was used for lubrication. It was also said that some unit commanders ignored recommendations of technical officers and didn't allocate sufficient time for tank maintenance.
The same place and time generally where the 5 Guards Tank Army was operating.

Art
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Re: IS-2: performance, variants, cost, units.

Post by Art » 19 Sep 2020 12:46

Losses (write-offs) of heavy Soviet tank and SP guns in 1944:

IS losses 44.png
From:
https://yuripasholok.livejournal.com/12740401.html
(the primary source is said to be the annual report of command of RA's tank and mechanized forces).

According to the same source there were 102 IS tanks on strength on 1.01.44 (compare with 67 IS-1 and 35 IS-2 produced in 1943) and 1914 (including 1266 on the front) on 1.01.1945. The production during 1944 was equal to 40 IS-1 and 2210 IS-2 (total 2250). That gives a balance of 102+2250-1914 = 438 or 13 tanks larger than reported losses. Probably that accounts for tanks given to the Polish Army.
The number of KV tanks on strength on 1.01.44 was 1067 (555 on the front) and on 1.01.45 - 581 (180 on the front), a decrease by 486 or 65 larger than reported losses.
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Stiltzkin
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Re: IS-2: performance, variants, cost, units.

Post by Stiltzkin » 20 Sep 2020 18:54

The author of the article makes the following mistakes (aside from the impertinent insults and hate pointed towards his readers and commentators apparently):
(i) The assumption that all AFVs were combat casualties. The German irrecoverable rate was usually set at 0.15, the Soviet at 0.4, this of course changes if battlefield control cannot be established, material losses are confined to the side that is frequently repelled, hence the irrecoverable rate rises.
(ii) The assumption that all AFVs were engaged by the listed weapon types.
(iii)The assumption that all featured AFVs were lost on the EF (the ratio for 1944 was 0.64, in line with overall troop allocations). The author underpins his contention by stating that the "WAllies possessed no heavy tanks". Interestingly, the AT capability of the Western Allied forces seemed to have been superior to the Soviet ability to impose combat attrition on the German tank forces, but capturing abandoned vehicles can have the same effect, I guess.
(iv) No accounting for battlefield control (salvage and repair) and punishment factors. Granted the German documents rarely include these figures, but the AFVs sent to the zone of interior never made up a large share of the entire park.
(v) A general misunderstanding of the terms at hand ("irrecoverable"/"Totalausfall"/"burned"/"evacuated") and hence their juxtapose.

However if we actually go down that path, then we can conclude that Soviet monthly combat losses of heavy AFVs were in the range of German heavy breakthrough tanks quarterly losses (and that would be still optimistic).
TsAMO f38 on11371 d16 l11,13 lists Soviet combat losses of KV and JS variants as 2,784 in 1944. 932 repaired and reinstated vehicles of the Josef Stalin type.
Looking at the table above, this would indicate an irrecoverable rate of at least 0.55. Either Soviet Heavy AFVs (in this case: IS+KV+ISU-152+ISU-122+SU-152) were prone to breakdowns and suffered from technical difficulties during their offensives (this actually has some merit), or had to endure sever punishment.
Cleaning the German loss figures and adjusting them for battlefield control and respective front we would arrive at a loss figure of ~700-800, i.e.those AFVs that were destroyed and damaged as a consequence of enemy fire (including vehicles that were left on the battlefield but were still potentially damaged). Compare Soviet and German personnel losses for 1944 (killed, wounded and missing), they correlate well with material losses. Local engagements on the tactical level hardly differed from the experiences at Kursk.

Of course a better picture could only be established with a recreation of the engagements via unit records.

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Re: IS-2: performance, variants, cost, units.

Post by Art » 21 Sep 2020 19:47

Also from Pasholok - the number of ISU-152 available on 1.01.45 was 974, losses in 1944 - 369:
https://yuripasholok.livejournal.com/13009901.html
Production in 1943-45 was 1375, the numbers don't fully add up.

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