Steve (BTS): ROF of ISU-152

[Andrew H.]

I do think that the ROF for vehicle mounted 152 mm guns should be lower than the ROF for field pieces, simply because no matter how capacious the superstructure, it will be more cramped than the area around a field gun. Also, on at least some occasions the vehicle will be moving or turning, which would also slow things down.

But, assuming a relatively capacious superstructure, the ROF shouldn't slow dramatically. If 3-4 is what a field gun gets, 2-3 should probably be the ROF for a vehicle, with greens probably having about a 2, and reg/vets having a 3. Perhaps crack/elite can approach the ROF of a field gun.

There are other factors that could slow this rate down. If a vehicle is particularly cramped, for example, the ROF would be lower. Also, if the gun was particularly troublesome to lay, the ROF should maybe go down, at least if some of the laying delay would be on top of the loading delay.

I'm interested in how the proposed "fitness level" for CM2 would fit into this calculus. It must be the case that after firing dozens of 100 lb shells, the ROF would drop due to loader exhaustion.

I don't know if there is a need to model this directly in CM2, as there aren't many occasions where I've had one unit fire 25-35 shells consecutively, with no pause. But it might add a certain amount of realism, for some tanks with larger shells, if ROF dropped after a certain number of shots in a specific time frame.

On the other hand, I'm not aware of any battles in which loader fatigue directly played a role, so perhaps this would best be not kept track of individually, but left to scenario designers. That is, a scenario could start with certain heavy tanks in poor physical condition to simulate having just fought an all out battle (when they are counterattacked or whatever).

[Skipper]

Jason,

I dont disagree with what you say, but every rule has exceptions. Out of 21 Ferdinands KO'd and abandoned around Ponyri (Kursk salient), 1 was destroyed by a direct hit of 203mm HE round in the roof. I think, it must be this one:

[Freak]

One thing about them Russian supporters: they sure like to show off their kills

(in jest)

[Skipper]

I am russian, not "supporter".

I posted this picture to see if anyone would argue that it was a mobility kill.

[Roksovkiy]

That picture of an Elephant has been blown by its crew, from an internal explosion outwards. Many Elephant were immobilised at Kursk and subsequently blown by the crew. The same pictures exist of a Tiger II with the turret of blown by its crew during budapest, and even the Maus with its turret blown by its crew after it broke down from Kummersdorf on its way to fight the Russians. A 155mm Artillery was pictured only slightly denting the front of an Elephant. 203mm Artillery would not have this catastrophic result.

[K_Tiger]

Whats up with re-targeting?? could be possible that the crew must do it after the shooting.

And the smoke the 155mm gun produce we must implement into the ROF discussion.

Sure, its a nice toy, but not really against tanks maybe in ambush situations.

[JasonC]

Yes, an 8" KOed one of the elephants at Kursk. But it did so because it scored a direct hit on the commander's hatch. So says the Russian breakdown of causes of Elephant kills. Another one was destroyed by a direct hit from an aircraft bomb, though - so there are two possible sources of that photo. Aircraft bombs can carry an order of magnitude more HE charge than artillery shells.

[Skipper]

Out of those 21 Ferdinands in the report, only one is listed as "set on fire by the crew" and another four as "set on fire" without mentioning by whom.

That 203 mm shell has actually hit TC hatch. 100 kg of HE going off inside the combat compartment - may well be the one in the photo.

[JasonC]

On the ROF of vehicles vs. field guns, I would not expect any difference from cramped space if the vehicle has a sensible arrangement. And the ISU-152 does from the interior shots I've looked at. Your muscles do not move any slower inside a vehicle than out. And field guns generally keep the ammo well away from the piece itself, which is not possible inside an AFV. The trip from stack to breech is actually shorter, not longer.

The only exception might be single gunner vehicles, rather than a pair to work it. That could indeed lower the ROF - although e.g. in an M-109, essentially all the loading is done by one man. (The assistant gunner is the 5th crewmember. He operates the elevating hydraulics - as opposed to the gunner's traverse - and can help with the breech if something goes wrong, etc).

As for the issue of crew fatigue firing 100 lb shells, yeah your hams and delts get a bit sore. Your arms sometimes shake. But understand, the period lifting the shell is a fraction of the time operating the gun, and most of the other tasks - while rapid - are light work. In the case of the ISU-152, the loader only has to open the breech and load the actual shell, while the second loader does most of the other things one guy does in the M-109. He is thus resting for ~10-15 seconds between "lifts".

Anybody who lifts weights can tell you that lifting 100 lbs and then having breaks between will give you a nice workout, but it hardly gets undoable in a period of 20-30 minutes. You can do 100 reps, which is more ammo than a gun carries and much larger than realistic fire missions. In practice, you get called upon to do it 6-12 times in one engagement period and then there is a break. It is work, but you don't have to be Conan. I've seen men who weigh 145 lbs do it rapidly.

[K_Tiger]

Jason..seems you see it to easily to lift a 100lbs bullet...the poor crewmens could not stand up inside or choose a "good" position like in a training-gym..

A other fact is, they could not lay down the bulletts in front of the breech or elswere (for a fast reload)...they must put it out of the storage-box and with other 4 men inside..puh..isnt really a dream to be a loader of a 155mm sp gun..

[kipanderson]

Dan Robertson, hi,

Yes, I agree with what you say about the British figures for the 122 gun. In fact British penetration figures do tend to be “generous”. I realise fully they are based on their own 17pdr ammunition.

The wargamer.org estimate of having to increase Russian figures by 5% to bring them up to the same basis as British figures I do not agree with. I believe the figure should be more like 20%. It will be very interesting to see what Charles goes for; after all he is the one that counts. He will not please everyone.

When it comes to greater variation of outcome I agree with you. One just has to be careful that this does not turn into an excuse to “lower” the average penetration figure.

And finally, yes, I have heard that Lorrin Bird is the guy for this stuff. I greatly look forward to his coming book.

All the best,

Kip.

[JasonC]

Um, KT, I am not making it up. There are crossed cannons on the class As hanging in my closet. I loaded 155mm SP (M-109) for my artillery training at Fort Sill OK, and tested on them regularly during my reserve service. My own unit used 8" self-propelled, the M-110, but all cannon-cockers trained first on the M-109 and had to check out on it regularly, since it is the most common piece used in the US Army today. The weight of shell for the M-109 is the same as the ISU-152, it is a cramped AFV interior, and the loading is done by one man instead of two. The shells for the M-110 weigh 200 lbs, and are lifted by two men in a cradle, then passed to the hydraulics on the gun itself. Ordinary teenagers and young twenty-somethings, in good shape after basic but in no way exceptional otherwise, had no difficulty doing it.

I don't know why this is so impossible for people to grok. Men designed these guns because they wanted something men could use. They are not Maus blackboard pipedreams, and equivalent pieces have been used ever since in every modern army in the world. The size of common field pieces tops out at 155mm because they can be run reasonably easily and give the greatest weight of shell possible for which that is still true. The implict idea behind the skepticism, that it is somehow an impossibly huge weapon to run, is simply poppycock from people who have no idea what they are talking about and have never been near, let alone used, a similar item.

Also, the shells in the ISU-152 were on ready-racks on the left side of the vehicle behind the gunner, which is the loader's position inside. The first two in each of the two racks are about level with his eyes, tips facing backward. He would face that wall, craddle the shell in his arms, then turn his whole body toward the back of the vehicle, then around another ninety degrees to facing the breech. In goes the shell, and then the assistant loader takes over for ramming, powder, closing the breech, etc.

In the M-109, the ready racks are at the back and a bit higher, but otherwise similar. Well, except you pull them out lengthwise toward you, which is harder to do than picking them up from their long side - but it lets them be stored more safely, seperated from each other in their little "silos". And often we'd jerk-lift the shells up off the floor, where the ammo-prep crew left them fused, after handing them in the back hatch from the ammo vehicle, in battery position. It just plain isn't that hard.

[ 06-05-2001: Message edited by: JasonC ]

[kipanderson]

Hi,

The British estimate of the rate of fire of the ISU 152 is clearly based on their estimate of what would be expected from a British crew. There is no reason to believe Soviet crews were any less capable.

Just to remind you, the British 1947 estimate was 2-3 rpm.

All the best,

Kip.

[Jeff Duquette]

Kip:

Are you by chance familiar with the Russian BIOS report pulled togeather in 1945-46. Generated from -- I think -- captured German documents detailing Russian equipment testing?

===========================

As to the rest I reckon I would have to strongly agree with Jason's points. I did a fair bit of loading in the cramped M48A5 with a 105mm shoehorned into a turret meant for a 90mm. Recoil was pretty much all the way to the back end of the turret. God help you if you were between the breech and the back of the turret when the gunner yelled "On the way".

The rounds weren't 100 lbs apiece but they were relatively heavy...one piece rounds. I guess I could easily load at a rate of 4 to 5 seconds per round. Assuming the rounds were coming from the ready rack on the turret floor next to me or behind me. Reported practical rate of fire for the M48A5 or M60 is somewhat lower than the above. No gunner is ever going to shot at 1 round per 4 seconds cause you couldn't hit **** if you tried at that speed.

I dont agree with Jasons techno-minutia comments, but the rest of his minutia seems pretty reasonable.

[ 06-05-2001: Message edited by: Jeff Duquette ]

[Michael Dorosh]

Jeff and Jason - tell me - if loading a 100 pound shell is such "light work" - what about the mere act of staying upright in a moving tank moving at speed? Was a loader not required to scramble all over the interior, pulling shells out etc., while the tank was on the move. I have ridden in armoured vehicles, and it is certainly not a bus trip. Compared to the driver or gunner who remains seated, the loader must have had a hell of a time - including just about all his muscle groups - just staying upright.

[ 06-05-2001: Message edited by: Michael Dorosh ]

[ 06-05-2001: Message edited by: Michael Dorosh ]

[Triumvir]

Jason,

I thought you were a gunner! By the way, I've seen people weighing 55 kgs -- almost the same damn weight as the round they were carrying -- help resupply a battery from trucks parked down the road. There was about 50 metres between the gun and the trucks, and about 10 shells per person.

Carrying rounds is surprisingly easy, especially once you balance them on the shoulder. I don't see that loading is that hard on the loader; we used to throw rounds onto the loading tray because of the loading tray's design.

[Jeff Duquette]

<BLOCKQUOTE>quote:</font><HR>Mike Said: Jeff and Jason - tell me - if loading a 100 pound shell is such "light work" - what about the mere act of staying upright in a moving tank moving at speed? Was a loader not required to scramble all over the interior, pulling shells out etc., while the tank was on the move. I have ridden in armoured vehicles, and it is certainly not a bus trip. Compared to the driver or gunner who remains seated, the loader must have had a hell of a time - including just about all his muscle groups - just staying upright.<HR></BLOCKQUOTE>

Who said it was “light work”? All I said was I could load faster than any gunner could practically aim and fire…assuming the rounds were in convenient ready racks.

In the M48 we didn’t do a lot of movement while firing. Contrary to the war movies you may have seen There were moving firing ranges (cant recall what they were called). But you basically moved from point to point…halted at each engagement point, fired your engagement than moved to the next point and did it again. Maybe they do firing while moving in the M1A1’s?

As far as the gunner being in some comfortable spot, I reckon if you’ve ever been cooped up in a gunners position on a long road march, with noting to do but look through a periscope that is none to steady, you might think differently about how cushy that position was….unless you’re a big fan of being catatonic for long periods of time, and not susceptible to claustrophobia.

Best spot on a tank is the driver’s position IMHO (unless you’re the gung-ho leader type). It’s fun driving a tank. In addition when you have to make quick halts you don’t get whip-lashed ala the TC and loader.

Loader wasn’t a bad position. You had your own hatch and you typically had your head up out of the turret during long road marches…air watch for make believe aircraft.

[Michael Dorosh]

No, I can't imagine the gunner was comfy, either...(!) and I do realize tanks didn't fire on the move - but they moved and fired! Meaning the poor loader is bouncing all over - hell, the way most of our 2-1/2 ton truck drivers go, being an infantryman in the back of one in the field is a workout too (had a sergeant once threaten to kill me for the way I was driving - on a hardened road, no less...)

Your points are well taken, as with anything, human beings have many variables - what about adrenaline? Surely this would help our erstwhile gunner with a 100 lb shell in times of crisis, etc. I think the point is that you can get really silly discussing things like ROF - and no one can proclaim to be the authority, or that they are right to the exclusion of anyone else.

Edit for characteristically stupid off the cuff comment that was completely historically untrue.

[ 06-05-2001: Message edited by: Michael Dorosh ]

[offtaskagain]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jeff Duquette:

.

Best spot on a tank is the driver’s position IMHO (unless you’re the gung-ho leader type). It’s fun driving a tank. In addition when you have to make quick halts you don’t get whip-lashed ala the TC and loader.

<HR></BLOCKQUOTE>

That's probably very true for the M1s. The driver is almost laid flat on his back. I've heard rumors that drivers occasionally fall asleep.

[ASL Veteran]

Here is some information about Tiger I vs Stalin tanks, again taken from “Panzertruppen Vol 2”:

<BLOCKQUOTE>quote:</font><HR> The September 1944 issue of the Nachrichtenblatt der Panzertruppen included a report from a Tiger – Kompanie that knocked out numerous Josef Stalin tanks in a short period:

(large snip)

The Kompanie commander made the following observations that were derived from their experience in fighting Josef Stalin tanks:

1. When a Tiger appears, most Josef Stalin tanks turn away and attempt to avoid a firefight.

2. In many cases, the Josef Stalin tanks let themselves engage in a firefight only at long range (over 2000 meters) and also only when they themselves are in favorable positions on the edge of a woods, village, or ridgeline.

3. The enemy crews lean toward evacuating their tank immediately after the first shot is fired at them.

4. In all cases the Russians strived to prevent a Josef Stalin tank from falling into our hands and with all means available attempted to tow the tank away or to blow it up.

5. The Josef Stalin can also be knocked out, even if a penetration of the frontal armor can’t be achieved at long range. (A different Tiger-Abteilung reported that the front of a Josef Stalin can be penetrated by a Tiger only at ranges less than 500 meters)

6. An attempt should be made to gain the flank or the rear of the Josef Stalin tank and destroy him with concentrated fire.

7. In addition, a firefight with Josef Stalin tanks should not be undertaken in less than Zug strength. Employment of single Tigers means their loss.

8. It has proven to be useful, after the first hits are registered, to blind the Josef Stalin by firing Sprenggranaten (high explosive shells)

Remarks by the Generalinspekteur der Panzertruppen:

1. These experiences agree with those of other Tiger units and are correct.

2. In regard to point 4 – it would be desireable for the opponent to have observed the same attempt by all of our Tiger crews. “An undestroyed Tiger may never fall into enemy hands!” This principle must be achieved by every crew member by exemplary operational readiness.

3. In regard to points 5 and 6 – At a time when there are 12.2 cm tank guns and 5.7 cm anti – tank guns on the Eastern Front just like the 9.2 cm anti – tank/aircraft guns on the Western Front and it Italy, the Tiger can no longer disregard the tactical principles that apply to the other type of Panzers.

Also, just like other Panzers, a few Tigers can’t drive up on a ridgeline to observe the terrain. In just such a situation, three Tigers received direct hits and were destroyed by 12.2 cm shells resulting in all but two of the crew members being killed.

The principles of Panzer tactics, that Panzers should only cross a ridgeline together, rapidly (leap – frogging by bounds) and under covering fire, or else the Panzers must drive around the height – were definitely not unknown in this Tiger Abteilung. Statements like “thick fur”, “impregnable”, and the “security” of the crews in the Tigers, which have become established phrases by other units and also partially within the Panzertruppe, must be wiped out and invalidated.

Instead, it is especially important for Tiger units to pay direct attention to the general combat principles applicable for tank versus tank combat.

4. In regard to Point 7 – This statement is correct; however, three Tigers should not flee from five Josef Stalin tanks only because they can’t start the firefight at full Zug strength. Cases will occur in which an entire Zug isn’t always available. Many times tank versus tank combat will be directly decided, not by the number of tanks, but much more by the superior combat tactics. Nothing is change in the statement that “a single Panzer is lost”.

5. In regard to Point 8 – In connection with this it may be stated that the Josef Stalin tanks can not only be penetrated from the flanks and rear by Tigers and Panthers but also by the PzKpfw IV and the Sturmgeschutz.

<HR></BLOCKQUOTE>

[Stalin's Organ]

An interesting post, but full of so many self-contradictions as to make it very confusing!

For example Stalin's turn and run at the sight of a tiger, or their crews bale out when first fired upon - so what is ist htat will kill the single Tiger that comes across them??

I wonder if "Stalin" tank includes some less-than-stalin types, much as all German SPGs weer "Ferdinands" or all Panzers were "Tigers"? Perhaps a few KV-85's and IS-1's are included here? Even early T-34/85's?

And perhaps those crews abandoning their vehicles were doing so because there weer the lighter tanks and had actually been knocked out at range?

[kipanderson]

Jeff Duquette, hi,

No, never heard of the BIOS report.

All my information, or the most interesting bits anyway, comes from the archives of the Tank Museum in Bovington, England.

The full title of the 700+ page report I keep going on about is,

Record of Foreign Weapons and Equipment,

Volume 1, USSR. 1947.

It makes clear that its sources are, equipment in British hands, German sources and the Soviets themselves.

It’s in the library at the Tank Museum.

I am always keen to know of any other such reports hiding somewhere out there.

All the best,

Kip.

[Skipper]

It is difficult to believe that such a mundane matter could give birth to a 5 pages thread

[ASL Veteran]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Stalin's Organ:

An interesting post, but full of so many self-contradictions as to make it very confusing!

For example Stalin's turn and run at the sight of a tiger, or their crews bale out when first fired upon - so what is ist htat will kill the single Tiger that comes across them??

I wonder if "Stalin" tank includes some less-than-stalin types, much as all German SPGs weer "Ferdinands" or all Panzers were "Tigers"? Perhaps a few KV-85's and IS-1's are included here? Even early T-34/85's?

And perhaps those crews abandoning their vehicles were doing so because there weer the lighter tanks and had actually been knocked out at range?<HR></BLOCKQUOTE>

I have to admit that I have trouble with the bailing out part too.

[Username]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Skipper:

It is difficult to believe that such a mundane matter could give birth to a 5 pages thread <HR></BLOCKQUOTE>

I believe that Steve's remark about the Elephants abilities and the SU's atributes started this.

Also, I think that CM2 fever is starting.

Lewis