Any elevation offset for DF gunnery in heat shimmer?

[John Kettler]

I know the new game has additional negative gunnery modifiers for really hot weather, and as someone who spent seven years in Arizona, quite a bit out in the desert and mountains in the summer (as hot as 120 degrees F.), I recall that an observer on an eminence can see much better into heat shimmer than can someone looking across the desert floor. Not only is the disturbed optical path length less than that when viewing across the desert floor, but it seems to me that on any sort of hill or eminence at all, it would be cooler as well, making for a better optical environment in and near the gun.

Theoretically, then, an AT gun firing down into a valley or similar on hot weather modified days should be able to see better for much of its LOS to the target than even an unbuttoned tank could see while on the burning, shimmering desert floor and seeking to engage either targets also on that floor or the aforementioned AT gun on the hill or other eminence. Does CMAK even attempt to model this?

Also, is the 88 in CMAK treated as being rangefinder equipped? It seems to me that that might help explain what happened at places like Halfaya Pass and why the 88 developed such a murderous rep in the Western Desert. On the other hand, if we take WW II ordnance expert Col. G.B. Jarrett (founder of APG Ordnance Museum and the man who personally reworked German 75mm AP shells to give the Grants an effective AP shell) at his word, the on mount, quick focusing 48 inch telescopic sight allowed kills at 4500 yard range (80 tank kills from 5 x 88s) at Halfaya Pass, and yielded a weapon of such deadliness that he says "The Afrika Korps was defeated because the Allies could commit more tanks to the 88's sights than the guns could possibly shoot." The information and quotes in this paragraph are taken from Jarrett's book WEST OF ALAMEIN, in the curiously unnumbered section "88 Anti Tank Guns." Fortunately, Rommel never had all that many 88s.

Col. Jarrett also says when the 88 was dug in or concealed by a rocky outcrop, "only the barrel protruded, usually only six to eight inches above the ground. In the shimmering desert heat haze, it was impossible to see and since the 88 could easily score a devastating hit at 4,500 yards with its special quick focusing scope, it could not be spotted until it was too late."

To put it mildly, this does not seem to suggest that heat shimmer was much of an impediment to the 88 at least, especially given that Jarrett goes on to remark, "sights were so accurate, gunner could decide which side of the bow plate he wished to hit at 4,500 yards."

I welcome feedback on these matters from BFC, the grogs, and from those with experience in scorching desert environments. Would love to know the distribution of Matilda kills at Halfaya Pass as a function of range. Would also love to know the rounds per kill for those 4500 yard kills, particularly since those 88s were firing "tungsten

carbide shots" (relatively scarce PzGr40 or "T" in game parlance). Can anyone produce the relevant German AAR?

Regards,

John Kettler

[ January 21, 2004, 03:49 PM: Message edited by: John Kettler ]

[John Kettler]

Bumping this in hopes of getting real answers to serious questions.

Regards,

John Kettler

[Soddball]

John Kettler is a weatherman, and so is Michael Fish!

[Moon]

Heat haze isn't simulated in great detail, no. It's basically a negative to-hit and spotting multiplier under IIRC very hot conditions, and applies to all units equally regardless of height.

As for the 4,500 years... I find it hard to believe that any kind of optical system, rangefinder or not, would be able to offset the effects of heat haze and allow anybody to see anything, let along fire, at such distances. Optical systems can improve contrast, light gathering and all that, but they cannot undo heat haze. Therefore I think that the 4,500 yard hits would not really have taken place during mid-day.

Martin

[Thermopylae]

Hell, the Abrams with its super keen nifty sights can only hit things out to around 3 klicks, so I imagine some WWII telescopic sight would have a much harder time.

[John Kettler]

Soddball,

Good to see you're not humor impaired. Who is Mike Fish?

Moon,

Were just anyone to make the 4,500 yard claim, I'd certainly challenge it, but Col. Jarrett occupies a truly unique niche, in that he was there, in theater, as an ordnance expert; he handled the equipment, and indeed not only organized the systematic retrieval and shipping back to the U.S. for test and technical exploitation of all sorts of Axis weaponry, but was decorated for his hands-on contributions, at real risk to life and limb--machining down driving bands on a spin-armed AT shells. With credentials like his, I'm in no rush to dismiss his statements out of hand. That's why I'm looking for as much detail as possible on the engagement, particularly AARs. Someone, somewhere must have the detailed info I seek. I daresay the British AARs make disturbing reading. Thanks for describing how CMAK treats/doesn't treat heat shimmer.

Regards,

John Kettler

[MikeyD]

Dumb question:

When was that fight at Halfaya Pass you're talking about, August or January, noon or dawn, sunny or overcast? Just because its desert war doesn't necessarily mean baking heat (now I expect to be told the battle was high noon, mid-August )

[Moon]

John, just to clarify - I don't challenge Col. Jarrett claims, unless he's claiming that the 4,500 yard shots were taken in heat haze conditions. What I said was that I presume they weren't, I couldn't really tell from your quotes. Like MikeyD just said, just because it was in the desert doesn't mean that there was a lot of haze. In fact many (most?) desert battles took place in the morning, when there would be next to no haze effect (yet).

While I wasn't there I do know a thing or two about what optical systems can do to improve vision, and eliminating haze isn't one of them.

Martin

[John Kettler]

MikeyD and Moon,

I claim no particular familiarity with the Halfaya Pass engagement, and I deem that you both make excellent points. That's why I'm seeking full particulars on the fight from someone with a better stocked library than my own. I can say, though, that the engagement was part of Operation Battleaxe, which ran from June 15-17, 1941. Am willing to believe that at some points of the fray, temperatures did meet the extreme heat criteria (summer in the desert), but my sources do not give the hour the attack began or timing details thereafter. Would welcome both.

Regards,

John Kettler

P.S.

Forgot to mention that Jarrett's quote about the dug-in 88 being invisible in the heat shimmer yet able to accurately shoot, hit and kill out to 4500 yards certainly seems to show that we're not just talking about early morning engagements under relatively benign optical conditions.

[ January 21, 2004, 08:00 PM: Message edited by: John Kettler ]

[JonS]

Reading that quote, I get the feeling he is talking about two different (but related) events.

4500 yards is what? 2 1/2 miles, which is about 4km. That sounds suspiciously like the longest ever verified engagement by an 88 in the desert ending in a kill (and it took a bit of bracketting to get that kill).

The fighting at Halfaya Pass*, with the guns dug down, was not where this occured. Especially not in the haze - and especially not when the guns were right down near the surface where the haze effect is most marked.

What we end up with is

1) the 88mm could kill at long range under certain conditions, and

2) 88s were hard to kill when they were dug down, and were hidden in the haze.

A superficial analysis of that gives us "In any given engagement the 88 could always kill at long range, and was hard to kill because it was dug down and hidden in the haze."

* Incidentally, the fighting at Halfaya could have either been in Brevity, Battleaxe, or Crusader - it's not clear which is being talked about. The environmental conditions were different during each engagement.

[Michael Emrys]

Originally posted by Moon:

As for the 4,500 years... I find it hard to believe that any kind of optical system, rangefinder or not, would be able to offset the effects of heat haze and allow anybody to see anything, let along fire, at such distances.

Indeed, maintaining a shell in flight for 4,500 years must represent a technical triumph of the first order requiring a truly massive propellant charge. Messers Krupp are to be congratulated. What's more, target lead for such a long shot must have required considerable skill and facility with computation. Maybe those Germans really were Übermensch! But then, as we know, it was all to no avail. Clearly yet another instance of German over-engineering I fear.

Michael

[tar]

Indeed, maintaining a shell in flight for 4,500 years must represent a technical triumph of the first order requiring a truly massive propellant charge. Messers Krupp are to be congratulated. What's more, target lead for such a long shot must have required considerable skill and facility with computation. Maybe those Germans really were Übermensch! But then, as we know, it was all to no avail. Clearly yet another instance of German over-engineering I fear.

It may be a bit too early to tell for sure. Perhaps they'll win the war in another 4436 years? Although I guess I must concede some of the over-engineering complaint. Who needs a 4,500 year projectile for a 1,000 year Reich?

[Michael Emrys]

Besides, what if when the projectile reaches the point of aim it turns out the tank is not there? Maybe they stopped along the way to have a cuppa? Or had to fall out to do maintainence? I think the butterfly factor comes into play here, and the Germans were notoriously bad with that one. All the war movies I've seen prove that beyond doubting.

Michael

[JasonC]

The Germans did not massacre 80 Matildas at 4500 yards at Halfaya pass. They destroyed a dozen or so, at ranges down to a km.

In Brevity the Germans weren't holding the position yet. Only Italian gunners were there. The Brits achieved surprise with armor - not Matildas, just cruisers - and overran the position for the loss of 7 tanks. This was in May, only a month before. The operation failed farther on and the Germans recaptured the position, and installed 88s there.

The 88 positions have been described as "sandbagged" by the Germans, and as "stone sangars" by the Brits. They evidently were both, with low walls of piled stone supplimenting sandbags. The ground was hard, solid rock being hit not far below the surface, making it impossible to sink deep positions. But the emplacements covered the guns up to a few inches below the gun, allowing full traverse.

A big part of the problem was clearly that cooperation with artillery was badly wanting. When the Brits eventually took the position (in November, in Crusader), arty helped, and photos of the aftermatch clearly show some 88s knocked out by artillery fire (blackened, recoil tube dismounted, walls collapsed by blast, etc).

In Battleaxe, the Brits fielded 135 Matildas all told. They had significant problems with mechanical breakdowns. Total losses in the entire operation - which was far larger than the fight at the pass - were 91 tanks, of which 58 were Matildas, 29 were Cruisers, and the rest were old lights. Reduction in operational "runners" was larger than total write offs, by about a factor of 2. Some of those are damaged but recovered, many of them are the breakdowns.

The unit that controlled the Matildas was the 4th armoured brigade. It was cooperating with an Indian infantry division. That division attacking in three columns, right center and left. Only the right column was directed at the pass. The bulk of the formation was deployed inland, on the higher ground above the escarpment, conducting a right wheel behind the pass.

The ease with which the pass itself had fallen in Brevity a month earlier undoubtedly encouraged the Brits to try again. The point of the pass prong was to open the coast road. The bulk of the division avoided the pass, and was to take objectives behind it - notably Fort Capuzzo (of which more below). The road prong was supposed to link up with them, and allow easier trucking up to the positions they had reached, in place of a long trek through the desert south of the escarpment.

The armor that supported the coastal prong was the 4th RTR. The specific unit engaged at the pass was C squadron, 4 RTR, which had a few old light tanks as command vehicles, and Matildas in the line platoons. This is a *company* sized unit. One Matilda and one light tank survived the engagement. The "slaughter" at Halfaya pass in Battleaxe consisted of the loss of a single company of Matildas - a dozen or so tanks.

While it was happening, the other prongs captured Fort Capuzzo beyond the pass, for a loss of 5 tanks. Then the Germans sent their armor and counterattacked. They fought a running battle with the different, cruiser and crusader equipped 7th armoured, which they knocked about handily. 15th Panzer retook Fort Capuzzo. 5th Light aka 21st Panzer flanked the Brits on the southern, desert side, away from the escarpment. The elements of 4th armoured with the Indians west of the pass, acted as a rearguard for the retreating Brits. Essentially the Germans ran rings around the main body of Matildas while smacking the cruisers. The main body then had to withdraw.

In addition to German 88s, throughout this fighting the Germans enjoyed the support of Italian guns, field and AA, and their own PAK, including 50mm with APCR. Plus 100 tanks. The whole force managed to kill 91 British tanks over several days. Not 80 by the 88s alone in one engagement. Clearly the 88s closed the door at the pass, which had been "open" a month earlier. They killed a tank company, not a tank brigade.

In November the Brits attacked again. Part of the attack included an assault on the same position at Halfaya pass. This fight was known as the battle of the Omars, after Sidi Omar and Omar Novi, two positions adjacent to the pass proper, on its inland flank - 5 (Novi) and 10 (Sidi) miles away from the pass. Another position involved was point 207, which is like an inland "bastion" defending the immediate upper side of the pass, between it and Sidi Novi but farther south than a straight line between them.

This time they coordinated better with artillery, and infantry took the positions. The supporting tanks were, however, badly handled again and basically wiped out. Specifically, the first attacks had the support of 32 infantry tanks. 11 were knocked out by mines before reaching the Axis positions. The rest then fought with the Axis guns, with only 9 surviving the fight - so14 were taken out by the guns. A reserve squadron was then added, 16 more, bringing the total back up to 25. This fought for the next position. 3 more were lost to mines, and guns got 19 more, leaving only 3 runners. Infantry nevertheless took the position. The Germans managed to get armor there to counterattack, but 25 pdrs brought up in the meantime successfully stop it, KOing 12 German tanks.

Thus, in the Crusader fight for the pass and the Omars in November, the Brits lost another 45 infantry tanks. 14 of them to mines, 31 to artillery. Some of these were probably repaired, as this is a tactical report of declines in runners, not a armor HQ tanks on strength or in repair type report. There is no question, though, that lots of I tanks were again KOed by guns. But not 80. (Someone might have been misled by the total number of wrecks on the field after it was finally taken in November. That would include tanks lost in all three fights).

The guns that inflicted this damage in the Omars fight - those 31 - were rather more numerous that just the German 88s. There were 4 88s, plus 8 Italian 75s, 8 German 105s, 4 Italian 65s, and "some" Italian 47 ATGs. The smaller guns were probably ineffective, but even the Italian 75s were useful. Moreover, the 88s were at the first of the two fights, and were KOed. They weren't part of the arty force that got 19 more in the second part of the fight (which included the 8 105s). Meaning they probably got 1-3 each - while being taken - not 80 with 5 or 16 apiece, without being hurt.

Why the dramatic difference compared to Battleaxe? The attackers have twice as much armor initially. But after running through the mines, only about a third more. The main difference would seem to be better coordination with the arty, which undoubtedly helped suppress the guns, and blind with dust those that weren't taking cover. The attackers still lost most of the tanks that made it far enough to engaged the guns - 57% of them. That did not however stop the attack this time.

I submit that if the picture of infallible kills at 4km ranges ("pick which half of the bow plate") were true, none of these engagements make any sense. None of the attacking tanks would have survived. 4 88s can fire 21 rounds in less than a single minute. If they could even kill a tank per minute they would have destroyed the mine survivors in 5 minutes, even discounting help from 8 Italian 75s. Evidently they could not. Probably because visibility (from arty dust) did not allow it.

In Battleaxe, in contrast, they reduced a squadron to 2 tanks. Which means each 88 got about 3 kills. 3 kills beyond range of reply was simply enough to make the tactical position unassailable. Since they had stacks of shells, they only needed 5% to 10% accuracy to do this. Firing opportunities are not scarce if visibility is clear. Ammo is not scarce. Enemies are scarce. It does not take high per shot accuracy to deal with all the enemy can afford to send.

For what it is worth.

[ January 22, 2004, 03:54 PM: Message edited by: JasonC ]

[JasonC]

Incidentally, what does he probably mean by the comment about which half of the bow plate? I think he is talking about the precision of the optics as to the aim point. Half a mil at 4500 yards is half of 4.5 yards, is about 7 feet. He was probably dramatizing what that 7 feet meant, as "from one side of the front of the tank, to the other".

On a sight calibrated to the mil, a good gunner can typical "split" the nearest mil setting, and so get about half mil accuracy - in the *point of aim*. That doesn't mean the round is going to go there. It means a straight light ray from the gunner to the target will be within 7 feet of where the gunner is pointing the sight, if he adjusts that sight perfectly.

The actual round suffers dispersion from shot to shot, a lot more than half a mil. Not to mention the error in the "quadrant" (elevation of the tube), from range estimation. And shot to shot variation in the range from the ballistics of the gun, besides ranging error. The gun is not going to shoot within seven feet of any spot you select on every shot, at 4500 yards. It is not a laser cannon.

[John Kettler]

JasonC,

Thank you for your customarily rich in detail reply, thanks to which I am now considerably less ignorant concerning the topic under discussion. I knew the Italians were at Halfaya Pass, but the details were dim. I remember reading about them years ago in whatever Paul Carell book covered North Africa, and I clearly recall that the Italian gunners were praised for their skill, bravery, and professionalism, being cited as examples of what the Italian soldier could be when properly cared for and led.

Regards,

John Kettler