Home Forums WWII A few odd snippets recently discovered serendipitously

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  • #138507
    John D Salt
    Participant

    While looking for something else entirely, I recently tripped over a (very messily reproduced) copy of “Operational Research in North West Europe”, a summary of the work of 2 ORS, at

    https://apps.dtic.mil/dtic/tr/fulltext/u2/a951850.pdf

    It does not seem to show up on a normal search of the DTIC site, which is a shame. A nicer copy is doubtless held by the National Archive at Kew, under piece number CAB 106/1017, and lots of the material will be familiar to anyone who has Read Terry Copp’s “Montgomery’s Scientists”. Several of the reports are material I have previously filleted, and the artillery weight-of-fire information is admirably summarised on Nigel Evans’ excellent Royal Artillery pages and in Dave Rowland’s “Stress of Battle”.

    Here, I present a few snippets I have chosen, simply because they were new to me, and I thought gave some useful indications about matters of interest to the WW2 tactical wargamer. The ballistics of air-launched rockets being all over the place like a mad badger’s breakfast is a familiar theme, but there are also bits that touch on the ineffectiveness of petards against pillboxes, likely detection range of anti-tank guns, the effect of cratering, recovery times from neutralisation, and the difficulty of telling one kind of bang from another.

    The four-level classification of morale effects I have already mentioned in the “rules of thumb” thread, but I couldn’t be bothered to take it out.

    All the best,

    John.

    – – – – – – – – – – – – – cut here – – – – – – – – – – –

    Op Goodwood:

    “In European terrains A/T guns, before they fire, can normally be so camouflaged as not to be seen by tanks; in these circumstances such guns usually hold their fire, even down to ranges of 200-300 yards, till they are certain of a hit.”

    “When using the tactics of fire and movement, where our supporting tanks are far away, say 2000 yards, it will take at least an average of 15 rounds HE before a direct hit on a dug-in A/T gun is scored; even when several tanks are firing this will take sufficient time for 4 or 5 of our attacking tanks to be hit. Where, however, supporting fire is at 800 yards or less, one of our supporting tanks should score a direct hit on their first round.”

    Neutralising effect of R.P. attacks:

    “To attain anything more than transitory neutralisation, R.P. attacks need to be repeated, perhaps as often as every 15 minutes, unless of course they are followed up on the ground.”

    Effectiveness of Petard mortar:

    “Petards fired from A.Vs.R.E. had little serious effect on the concrete of pillboxes, and out of more than 20 strikes obtained none had hit the front steel plate. Nevertheless, the enemy almost always surrendered. If however A.Vs.R.E. are to achieve any material effect and destroy determined defenders, they must get sufficiently close to hit this plate.”

    Accuracy of R.P. attacks:

    In the attack on Boulogne, 216 rockets produced 1 rangefinder destroyed and 1 gun possibly destroyed.

    “The figure for R.P. damage is good, when it is considered that in trials, 30 rockets are required to hit a tank, which presents a target perhaps 5 times larger in area, and where the attack is unopposed by Flak.”

    Effect of cratering:

    “A simple calculation shows that a density of bombs as low as 1 per 4 acres (a normal bombing attack gives a density of at least 5 per acre), a tank which cannot see and avoid a crater stands a 50% chance of falling into one in the course of a 1000 yds run. Alternatively, if the leading tank of a column can be employed as a pathfinder and, when it comes to grief, a second tank takes a new route and continues as leader, then, in a density of five craters per acre, 15 tanks will fall into craters before a safe path over 1000 yards has been found.”

    Rockets again:

    “…the chances of landing rockets inside gun pits are very small (not better than 1 in 700 for an emplacement 5 yds in diameter).”

    Artillery effects:

    “Against troops of the calibre of 183 Division (2nd grade infantry divisions) a bombardment of 1 1/2 tons per 100 yard square, carried on continuously for several hours, will have an overwhelming effect and paralyse all resistance. The effect will be less in built up areas or where other strong shelters are available. Concentrations of 1 ton per 100 yd square continued for only 20-40 minutes do not, however, produce at all the same mental and physical breakdown caused by prolonged bombardment with a weight not very much greater.

    Against the same troops, concentrations of 1/2 ton per 100 yds square and upwards, lasting for 20-40 minutes, will have a strong demoralising and disruptive effect, which may last for a short time afterwards and is apparently more than mere neutralisation.

    A weight of 1 ton per 100 yd square did not have a markedly greater effect than a weight of 1/2 ton; both were very effective and the greater weight is therefore possibly uneconomic.”

    “A density of 650-1300 Field and Medium shells per kilometre square succeeded in cutting all the line communications in the forward defences.

    A density of about 650 Field and Medium shells an hour per map square, or 1-2 shells every minute within 200 yards seems to have been enough to keep officers and everyone else firmly in their shelters.

    A density of about 2600 shells an hour per map square or about 6 a minute within 200 yards seems to have been enough to neutralise the quality of troops in these defences.

    There is an indication that our own casualties do not fall much with weights of fire of over 100 tons per kilometre map square put on the enemy.

    There is an indication that numbers of shells are more important than sheer weight of shell, and that pepperpots are therefore a most valuable way of increasing fire effect without much increase in weight of ammunition.”

    “All PW, including a number of signallers, confirmed that line communications were cut throughout the preliminary bombardment area within 1-2 hours of the start of the shelling. This gives a figure of 650-1300 shells (25pr and 5.5″) per kilometre map square to effect complete line cutting in areas of fairly elaborate earthwork defences. As far as could be seen, line was laid on the ground, or supported on trees and was not dug in.

    Four degrees of severity of morale effect can be distinguished; they are:

    (i) to stop movement,
    (ii) to stop firing — neutralisation,
    (iii) to produce some sort of longer term neutralisation which persists for a time when firing has ceased,
    (iv) to produce a complete collapse.”

    “Although in fact many different targets were engaged and re-engaged at different times, PW all seem to have been under the impression that they were shelled incessantly.”

    “Of all the 76 PW interrogated by us, none appear to have noticed either the Artillery Rockets or the Radio Proximity Airburst shells. Even an Artillery O.P., one L/Cpl. Hendig, who occupied a commanding position on the edge of the Reichswald and who was observing all the time, failed to notice anything unusual. It appeared that in the midst of the general unpleasantness caused by this bombardment, the particular properties of special weapons did not make any special impression.”

    “The great importance of keeping close to barrage or concentrations has always been realised. There is an indication in these reports that falling half an hour or so behind is equivalent to cutting down the weight of the bombardment four or five times, and perhaps more.

    How much it matters falling say 5 or 10 minutes behind cannot be told, but at least it can be said that keeping within a minute or two of the barrage instead of within 5 or 10 minutes must be worth quite a lot of extra fire power. Unfortunately with the huge predicted concentrations on a timed programme so often employed nowadays, it is our impression that the infantry are of necessity 5 or 10 minutes and often more behind and the value of such huge weights is therefore in considerable measure wasted.”

    #138510
    Tony S
    Participant

    Very interesting stuff. Primary sources, whether WW2 or earlier, are always fascinating, especially when they are actually analyses by professionals who were there.

    As an aside, I find it a shame that I didn’t realize how many really good books Terry Copp had written when I had him as my prof in school until long after I graduated. He was a great teacher though.

    #138511
    Steve Johnson
    Participant

    Fascinating stuff.

    #138512
    Albert of Winterpig
    Participant

    The petard has to be counterbalanced by the POW impression, that a none penetrating hit on a concrete position, reverberated through the structure and would feel to those inside as if it was about to collapse, even if it wasn’t.

    What is the quote, ‘Morale is to the physical as 3 is to 1.’

    I suspect the same can be said of rockets.

    #138528
    deephorse
    Participant

    Thanks for that information John.

    #138570
    MartinR
    Participant

    In John Foleys Memoir where he remembers bunker busting on the Westwall, he said that generally recalcitrant bunkers surrendered after being hit by an AVRE. If they didn’t, they’d bring up a Crocodile and hose it down with that, after which there wasn’t anyone left to surrender.

     

    "Mistakes in the initial deployment cannot be rectified" - Helmuth von Moltke

    #138755
    Nick Riggs
    Participant

    Good find, John!

    #138939
    John D Salt
    Participant

    The petard has to be counterbalanced by the POW impression, that a none penetrating hit on a concrete position, reverberated through the structure and would feel to those inside as if it was about to collapse, even if it wasn’t.

    What is the quote, ‘Morale is to the physical as 3 is to 1.’

    I suspect the same can be said of rockets.

    Indeed the OR folks themselves mention this on numerous occasions. Not only does rocket attack have a strong intimidating effect on the enemy, it is a considerable encouragement to friendly troops who witness it. It may not be entirely clear from my necessarily abbreviated account in https://www.thewargameswebsite.com/forums/topic/75-years-ago-today/ but when X Troop, 47 (RM) Commando attacked the weapon pits south of Port-en-Bessin with fixed bayonets after a Typhoon rocket attack, they successfully captured the obective — consisting of concrete emplacements — apparently without loss on either side, and without the defenders even opening fire, despite being plentifully supplied with ammunition.

    Generally, I reckon low-level air attack, multiple rockets, and the use of flame weapons have effects on morale greater than their destructive power would otherwise warrant. Very heavy HE may have a similar effect; Gunner Milligan mentions the impression the heavy rounds of his regiment’s 7.2-inchers was reported to have on the Germans, and a Petard mortar bomb, despite being lighter, holds the same amount of HE.

    All the best,

    John.

    #138994
    deephorse
    Participant

    I recall reading somewhere (and I think I know where, but I can’t find that book right now to confirm it) that even the threat of attack by Typhoons etc. was often enough to force German tank crews to abandon their vehicles.  This, despite the fact that they would probably have been safer staying inside the tank.

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