Monday 30 April 2018

Visibility

Here's a rather interesting analysis of the Tiger's commander's cupola by British tankers. It's no secret that the British weren't huge fans of German observation devices, but here is a pretty thorough list of its deficiencies, backed by a handy diagram.



As you can see, the Tiger has a pretty sizeable dead zone (30.5 to 36.5 meters) to the right and rear-right due to the position of the commander's cupola, which the British comment on as being an effective approach for infantry with anti-tank weapons. 

Let's compare this cupola to that of the KV-1S tank


Despite having a cupola in roughly the same place, the dead zone to the right and rear-right is only 11-14 meters, less than half as much as the Tiger. The KV-1S also sees slightly better to the left and rear-left, with a dead zone of 9-11 meters to the Tiger's 12-15. The KV-1S has worse vision forward though, a dead zone of 28 meters compared to the Tiger's 18. The field of view is also obscured by the gunner's periscope, which the Tiger does not have. On the flip-side, the Tiger's gunner is restricted to the narrow field of view of his gun scope. 

19 comments:

  1. "Here's a rather interesting analysis of the Tiger's commander's cupola by British tankers. It's no secret that the British weren't huge fans of German observation devices..."

    Apart from the usual obscuring attempts and cherry-pickings; the British examiners did like the German observation devices on the Panzer III and IV and called them "outstandingly good" - compared to "contemporary Allied vehicles." You also don't mention that this "analysis" whilst a preliminary report, was based on the Tiger H, while the Tiger E saw a re-design of the cupola in July 1943 with much improved observation. I don't know if you did that on purpose or simply having an axe to grind, but here's the missing excerpt you deliberately cut off:

    "In the Pz Kpfw III and IV commander's vision was outstandingly good (especially when compared with contemporary Allied vehicles), particularly in that he could see near ground all round the vehicle. The distance between the vision device and the edge of the turret, the slope of the turret roof and the height of the device above the general level of the turret roof, are the main factors determining whether or not ground will be seen near the vehicle in any given direction. These various factors were all well balanced in the Pz Kpfw III and IV. The cupola was centrally placed at the rear and narrowest part of the turret and allowed good vision to the rear and sides of the vehicle. Vision forwards was less good because the whole length of the turret was in front of the cupola, but this was mitigated to some extent by sloping the roof downwards from the cupola and further by raising the cupola
    above the roof. Compared with vision in other directions, commander's near vision forwards is not so important, as vision in this direction is also covered by the driver and hull gunner. In contemporary Allied vehicles the commander's vision device was placed to one side of a square flat-topped turret. This meant that on the whole vision was good in one direction (over the nearest turret edge) and liable to be bad in other directions, because of the distance between vision device and turret edge. The blind zone in the commander's field on the Churcrhill extended to within 120 feet of the right hand side of the turret, Also, because of the lowness of the periscopes on the turret roof, visual fields were badly obstructed by fixtures such as fans which projected above the general roof level."

    On the next page about the new Tiger E cupola and observation:
    "It would, however, appear from recent photographs that re- design of the cupola to improve observation of the ground near the vehicle has been necessary. It is interesting to note that the new design, as far as can be seen from the photographs, involves the use of eight high Episcopes in place of the direct vision blocks. Episcopes have not been used in cupola design by the Germans since the Pz Kpfw II."

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    1. The point of this article was to compare the vision of the Tiger and the KV-1S. Since the cupola of the Tiger E was not analyzed in the British source, I couldn't use the diagram for it. I don't know why you think this is a conspiracy on my part, perhaps if you go back in time and tell the British to include their analysis of the Tiger E cupola in the same document, I could use it as well.

      As for the PzIII, I was going to save that for a separate article, but you can have a quick peek at what the British write about that. From a description of the all-round vision cupola used in the Cromwell:

      "Rotation of the head through 68 degrees allows a view with the with the right eye which continues from the direction at which the previous field ended (line d parallel to line c) and by such head rotations the field is extended to about 180 degrees (line e as limit).

      These requirements are not realized either in the five block all-round vision device of the German Pz.Kw.III and IV or in the five periscope devices used in the Pz.Kw.II. In all these the units are equally spaced round a cupola with a small hatch allowing exit with difficulty, and in the Pz.Kw.III and IV the cupola projects considerably. Only about 70 degrees field is simultaneously visible."

      Diagram in question: https://i.imgur.com/4Sn29ty.png

      As you can see, the British had plenty of criticism even for these cupolas, and found them not up to their own standards.

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    2. Perhaps because of the bold statements?

      "Special Report on German observation ports and optical devices, Oct. 1942" compared German episcopes on the the Pz III and Pz IV to the observation devices on the Crusader III, Matilda II and Churchill II. Conclusion, "far superior all-around vision". Naturally, a report compiled in what, 1944(?) is going to rebalance those previous viewpoints.

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    3. The backbone Panzers had good, indeed excellent, vision arrangements *by early-war standards*. At least for the TC; German designers in general seem to have been rather allergic to giving the rest of the turret crew much in the way of vision devices.
      Hazarding a guess the Sherman already *at least* caught up, and the Brits started getting those in late '42...

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    4. Cromwell development started a hell of a lot earlier than 1944. And yes, like Kellomies says, the Matilda and Crusader were hardly pinnacle of tank design by 1942.

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    5. Kellomies, the British examiner of the Tiger H concluded in November 1944, that the "Pz Kpfw III and IV commander's vision" were still regarded as "outstandingly good", "especially when compared with contemporary Allied vehicles".

      https://imgur.com/a/o1IdiyR

      The Cromwell might just be an exception that got these previous design shortcomings fixed.

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    6. Note emphasis on "commander"; looking through a few photographs suggests he was the only fellow in the turret who saw much anything at all, as in what seems to have been the standard German practice the turret appears quite devoid of vision devices of any kind for the others. (I don't think the slits on the sides really count, plus about everyone had those in some form anyway.)

      One is inclined to suspect the other armies' habit of giving more or less everyone something to peer out of more than made up the difference, and as discussed in the article linked below the gunner having a wider field of view than the magnifying sight alone provides is a matter of some real consequence.

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    7. Yes, the full text of the report goes on to complain that the rest of the turret crew are rather blind, and the loader, even though he has a vision slit, can't actually fully use it since the ammo bin prevents him from turning his head.

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    8. I'd also point out that the word "contemporary" has two meanings; *present time period* and *same NOT present time period*, as in eg. "contemporary accounts of [some past war]"...

      The report repeatedly uses past tense when discussing the Pz III and IV cupola and the only Allied tank specifically named in comparison is the Churchill, for which the description "-- placed to one side of a square flat-topped turret" is certainly apt.

      No mention at all of the Sherman, which had a cupola generously provided with vision blocks plus a liberal allocation of periscopes for the turret crew. Though in all fairness the report seems to be specifically concerned with the commander's visibility rather than that of the crew in general; am I interpreting the cover page correctly that this was an addendum to a more comprehensive analysis of the Tiger?

      This rather leads one to conclude the comparison is made to *early-war* Allied tanks and parsing through some photographs of the things weren't winning any prizes for great visibility.

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  2. No gunner's periscope on the Tiger? Wonder if that caused "target hand-off" difficulties similar to those noted on the Panther:
    https://worldoftanks.com/en/news/chieftain/chieftains-hatch-french-panthers/

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  3. Interesting article, thanks.

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  4. "not centrally behind, but to the side of the gun" The commander needs the gun in his lap? Rubbish.

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    1. It's an explanation of why the Tiger cupola had poor visibility to one side. Why would you leave that out of a report on visibility? It's not a handbook on how to design tanks.

      The Pz III and IV did have the commander centrally located behind the gun, so it's not impossible. Even when the Pz IV went to the very long-barrelled guns, the commander remained behind the gun, in the central location.

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  5. No doubt the British observation was based on Tiger 131 which they captured in North Africa after a Sherman shell wedged between the turret and hull jamming it's traverse. World of Tanks with Richard Cutland gives a decent videos of what it was like in each of the crew positions and I agree in no place were there adequate vision devices. Indeed the poor driver only had one thin slit to look through and could not raise his hatch to look out because the hatch was offset. Which is ironic because over all the positions in the tank looked comfortable, there just didn't seem to be enough holes to look through. Which is strange because older German tanks and Panthers had fantastic turret cupola's with vision slits with moveable armor covers. My guess in this for this tank to operate the Commander would need to have his head exposed during combat. Perhaps the Germans just assumed the Tiger was invulnerable and would destroy all the enemy tanks before they got into close range.

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  6. Only very late Shermans had cupolas with multiple vision blocks - those with the T23 turret and those with very late 75mm gun turrets produced in the last year or so of the war.

    Most Shermans had a commander's cupola with a single Gerlach-type periscope that rotated through 360 degrees.

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    1. Ah, I stand corrected then. Admittedly I wasn't exactly doing any deep digging and just went with the first photos that gave a decent view of the turret roof.

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  7. How to reliably generate comments: include the word "German" or "Tiger" anywhere in the post. 10+ comments guaranteed :)

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    1. You could probably get pretty far with just "Tiger tank: discuss", yeah.

      Charismatic megafauna indeed.

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  8. by the way, Shermans had nothing to do with the capture of Tiger I 131 on Tunis. It was a unit of Churchill tanks (48 RTR) with 6 pounder guns...

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