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240mm artillery very slow - bug?


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YankeeDog,

Destruction of a tough pillbox or bunker would typically be done using a single howitzer for precision fire. Where a 100 meter bracket was good enough for FFE for field artillery, this was a matter of progressively walking the shells onto the target, with the goal of demolishing it, or at least crippling it with Fuze, Delay shells.

Regards,

John Kettler

Hi there,

I know that this particular post was a while ago but I thought that I might make a comment....

Picture13_zps936b0b95.png

Here is some data that I gained from a US manual...... at a range of 18000 yds the PE for a 240mm howitzer firing this particular ammo (HE...) is 36yds x8yds.....

What this means is that a single wepaon firing a given (say 100 rounds for theory sake) mission that is perfectly laid will have a beaten zone that is 8 x 36 = 288yds deep and 8 x8yds = 64 Yds wide.....

Just wanted to respond to the "precision fire" comment above. Now maybe it was intended in the above comment that these point targets were to be engaged using direct fire,.....

Anyway, my figures would be smaller if the range was shorter...... but certainly not able to hit a bunker without a hell of a lot of ammo......

Rob

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Hi Rob,

What this means is that a single weapon firing a given mission that is perfectly laid will have a beaten zone that is 8 x 36 = 288yds deep and 8 x 8 = 64yds wide.

Just wanted to respond to the "precision fire" comment above.

Nice post.

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Anyway, my figures would be smaller if the range was shorter...... but certainly not able to hit a bunker without a hell of a lot of ammo......

Well... yes and no. 240mm howitzers were definitely used knock out point targets like bunkers and fortified buildings; I've read multiple accounts of them being used this way so the tactic must have worked somehow.

Either they had plenty of shells and were simply willing to spend the time and shells to get that lucky direct hit, or the weapon was more effective than the raw accuracy figures would seem to suggest. I suspect it's actually a little bit of both.

Directly hitting a bunker in the sense of having the shell fall right onto the roof would indeed require a lot of attempts (on average) since bunkers usually have a pretty small footprint. But an absolute direct hit probably isn't required, and in fact isn't even necessarily the most desirable hit -- some heavy concrete bunkers like some of the ones on the Westwall had very thick reinforced concrete roofs that were designed to withstand direct hits from very large ordnance like aerial bombs and very heavy artillery.

What will often work better is near miss by a large shell or bomb set on HE delay, close enough that the shockwave created by the shell (detonating several meters under the earth) is enough to stave in one side of the bunker, or otherwise compromise it structurally. This gives something really big like a 240mm shell a somewhat a somewhat larger "likely KO" target area on a bunker.

I don't know exactly what the "likely kill" area would be for a 240mm shell on a typical bunker, and I imagine it would probably vary considerably depending on factors like soil type and condition, bunker construction etc. I do have a U.S. Army publication which shows expected effects of aerial bombs dropped with an HE delay fuse. Based on this publication, it looks to me like a large HE delay shell like a 240mm would probably only need to come within a few tens of meters to stand a good chance of damaging a bunker.

If you only need to drop a 240mm shell within, say, a 30m radius circle to have a good chance of rendering the bunker combat ineffective, then this reduces the average number of shells it would take to achieve an effective hit considerably. Still something that might take a couple of dozen attempts, but if the other option were direct frontal assault, this might be worth the time and resources.

18,000 yd. range is also long for this type of work -- this is probably a pretty typical range for "normal" fire missions by big guns, but not for this type of work -- AIUI, big howitzers would typically be brought quite a bit closer to the front line for this type of point target work. Of course, this could lead to greater risk of counterbattery fire, but that's another topic...

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There are not many good locations on the map from which to observe Le Ham. However, you do have a couple of lovely TRPs ;)

Yes, and I took a long time planning out this mission. In one version of my plan, I placed the TRPs to cover key points of Le Val, but in the end I decided to leave them be at the fortified line. The reasoning being that I assumed there would be some concrete bunkers (info given in the briefing), and I wanted to make sure I could direct fire against those targets with greater flexibility.

Now, as we know, there are no concrete bunkers, and I sorely missed my TRPs later in the mission, but I suppose that's how war is - intel is rarely completely certain.

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MikeyD,

And the powder's the easy part!

Rob Deans,

Assuming your groggy data and math are correct, that translates, for the firing distance shown, as 1 AS wide x 8 AS long. Not big at all. Is this the 100% zone or what? Given the distance you cite, the 240mm is being fired from 71% of the maximum range, this per the Wiki. This corresponds to defensive siting, typically with the weapon positioned 2/3 of range behind the line of friendly forces. For offensive operations, the weapon is moved up, such that 2/3 of the range extends into hostile territory. this is done to extend the weapon's reach.

http://en.wikipedia.org/wiki/240_mm_howitzer_M1

The Wiki talks about the use of the weapon for dealing with very strong point targets.

"The weapon addressed the requirement for super heavy field artillery capable of attacking heavily reinforced targets like those likely to be found along the West Wall. It was designed together with the longer ranged 8 inch Gun M1 and they both shared a related carriage.[3]

The 240 mm howitzer M1 proved very valuable against difficult targets such as heavy concrete fortifications.

The first operational use of the super heavy 240 mm Howitzer was by the U.S. 5th Army at the Anzio Beachhead in Italy in September 1943.[5] Its debut was an instant success, along with the 8-inch (200 mm) gun (which was deployed later at Anzio in April 1944) – super heavy artillery was used as counter-battery fire against German guns in their class.[5] Their fire was accurate enough to not only knock enemy artillery out of action but also to destroy targets as small as German heavy tanks.[5] US super heavy artillery also played a role in countering the infamous Anzio Annie railway gun and putting it out of action.[5]"

Anzio Annie was 32 meters long x 3 meters wide, thus just over 4 AS long and just under half an AS wide. It's also, barrel horizontal, about 4 meters high. This figures into the danger zone discussion below.

"In Italy, the 240 mm Howitzer was highly valued for its capability to destroy key bridges at long range.[6] Army Ordnance officers credited the "devastating fire power and incredible accuracy" of the 240mm howitzer in playing a decisive role in the Italian Campaign.[1] During the Battle of Monte Cassino, the weapon was used in the final destruction of the monastery at Monte Cassino already damaged by air attacks.[6]"

Here's a quick overview of bringing the M1 240mm howitzer into position. Begins page 76 of the PopSci magazine.

http://books.google.com/books?id=PiEDAAAAMBAJ&pg=PA76&dq=popular+science+1945+%22Biggest+Gun+On+Wheels%22&hl=en&ei=_erMTJrSG4Gknwf_vIkn&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDMQ6AEwAA#v=onepage&q=popular%20science%201945%20%22Biggest%20Gun%20On%20Wheels%22&f=true

Returning to the hitting the point target problem, there's more to it than meets the eye, considerably more. There is something called danger space. It's a function of target height, target width and angle of projectile impact. Classically thought of in naval warfare terms, it's equally applicable here. The link describes and illustrates the concept.

http://www.kbismarck.org/forum/viewtopic.php?f=36&t=2631

For our purposes, target height may also be deemed to extend some distance into the soil. Likewise, not only are hits on the bunker proper good, but so too, and maybe even more so, as YankeeDog noted, are hits which "submarine," go under the bunker's foundation and detonate, rather in the manner of torpedoes which don't hit the ship's hull but instead detonate beneath the keel, breaking the ship's back. I have no idea whether West Wall bunkers and other such targets had reinforced concrete aprons to prevent this.

So, there's apparent target size and effective target size, and near misses in deflection further increase that effective target size. Further, things radically improve with a spotter plane in the loop, because overs or shorts, assuming line's right, can be rapidly corrected, rather than successive brackets having to be fired.

Shoots of this sort are generally done with one gun, the most accurate available, because it allows much greater control over the numerous variables in the gunnery calculations. Such a shoot is a gunner's dream, for it's all about the art and science of gunnery, rather than pumping out rounds as fast as possible upon a designated target. Think of the difference between making languorous love vs wham bam, and you'll begin to understand what I'm seeking to convey.

Regards,

John Kettler

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Assuming your groggy data and math are correct, that translates, for the firing distance shown, as 1 AS wide x 8 AS long.

You might want to check your calculator. Based on the figures given, the 100.0% zone is 8AS wide by 36AS long.

The first operational use of the super heavy 240 mm Howitzer was by the U.S. 5th Army at the Anzio Beachhead in Italy in September 1943.

I like Wikipedia and use it a lot, especially as an entrée or an aide mémoire. It is, however, always worth remembering that Wikipedia is a general purpose encyclopedia, with all the problems that general purpose encyclopedias have.

Hint: Operation SHINGLE had a D-Day of 22 January 1944.

things radically improve with a spotter plane in the loop, because overs or shorts, assuming line's right, can be rapidly corrected, rather than successive brackets having to be fired.

This grossly misunderstands the role of aerial OPs. Overs and shorts can be rapidly corrected by a ground based observer - assuming he has visibility of the target area. Visibility of the target area is the main advantage the aerial OP offers.

Observation doesn't remove the basic requirement for bracketting. In fact, observed fire in WWII - regardless of platform - practically always required bracketting to get rounds on to the designated point of aim. Unobserved firing doesn't require bracketting; there's no point applying a correction when you don't know where the first round landed.

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JonS,

When he listed the PE, he said. "at a range of 18000 yds the PE for a 240mm howitzer firing this particular ammo (HE...) is 36yds x8yds....." I did my AS math from that.

(goes off for a bit)

Aha! He wasn't clear in explaining how he got that other set of numbers. If he indeed multiplied the PE figures by the figures in the table, then we have a different problem altogether. Also, his math is off. Considerably.

If the total error in range is 36 PE, that's 36 x 36 yards or 1296 yards x 8 PE in deflection or 64 yards. Multiplying the two figures, we wind up with the 100% zone you calculated and not his 8 x 36 for 288 yards in range and 8 x 8 or 64 yards in deflection.

The previously cited heavy artillery study states, on Pages 6,7, the 240mm Howitzer M1 entered combat on January 28, 1944. Thus, it was not available from D-Day of Operation Shingle. The 240 was late to the party for want of an approved tractor.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA510939

The leverage of aerial observation in getting fire on the target may be seen in the statement in Eyes of Artillery: the Origins of Modern U.S. Army Aviation in World War II,by Raines, that it took the Royal Artillery an hour and 15 minutes to get the divisional guns all on target during the invasion of Syria, something done in "a few minutes" by aerial observers at Larkhill, England.

http://books.google.com/books?id=n4H3B7zGwZwC&pg=PA31&lpg=PA31&dq=aerial+observation+for+artillery&source=bl&ots=qioaEg2_Qg&sig=OY0bruIuDHeZnei_iv304gui3KU&hl=en&sa=X&ei=srLHUf3ZGuzJ0AHd7IDoCQ&ved=0CDoQ6AEwBDgK#v=onepage&q=aerial%20observation%20for%20artillery&f=false

This is a book I think you'd love--groggy, well-documented, engrossing and readable.

Regards,

John Kettler

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Your calculator is still broken. The figures in the table (36yds and 8yds) are one standard deviation for PEr and PEd. Multiple those by 8 (or four std deviations either side of the point of aim) to get the 100.0% zone.

This is a book I think you'd love--groggy, well-documented, engrossing and readable.

Broken clock analogies aside, I somehow doubt that any book you recommend so glowingly would hold much novelty or interest, even if it were the slightest bit on topic.

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JonS,

I'll have to revisit the math later. As for the book, if you reject so much as looking at it because I recommended it, that's your loss. I read 20+ pages; you've read zero. Who is likely to be better informed in consequence? I invite others in this thread to take a look for themselves and report back. That way maybe you'll be able to get past your rather pronounced bias against me.

Regards,

John Kettler

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JonS,

Correction. Should've read

...if you reject it without so much as looking it...

Bulletpoint,

Cracked me up! And did you notice the auxiliary elevation control device (that window thing)? Never seen that before. Great footage of a moose of a howitzer and in high res. Terrific find.

Regards,

John Kettler

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Well... yes and no. 240mm howitzers were definitely used knock out point targets like bunkers and fortified buildings; I've read multiple accounts of them being used this way so the tactic must have worked somehow.

Either they had plenty of shells and were simply willing to spend the time and shells to get that lucky direct hit, or the weapon was more effective than the raw accuracy figures would seem to suggest. I suspect it's actually a little bit of both.

I was under the impression, possibly mistaken, that the truly heavy pieces like the 240mm howitzer were under the control of artillery groups built specifically for this sort of mission, with specialized survey and geolocation units to enhance their accuracy.

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JonS,

Yes you are correct..... The 100% zone (or in layman's terms, the beaten zone, the area where all the rounds land) at that range, with that ammunition, is as stated....8 x PEr by 8 x PEd. You and I were both invovled in a conversation last year about this very topic... The weapon system was the mortar but the theory behind what we are talking about here is the same... Just the PEs change.....

John Kettler,

Yes, please do assume that the groggy math is correct...... Are you a gunner?

What's important to understand is that the PEs for range and bearing (deflection) are the BEST consistancy (the tightest pattern on the ground) that can be achieved vs the best accuracy (are the rounds on target) that can be achieved. The PEs are influenced by range, the trajectory and the ammunition fired. They are fact and the way to interperet the PEs is as I have shown... Whether there is an air OP or the FOO has xray vision matters only in placing the 100% zone (though in practice it is the 50% or the 82% zone) centred on the target. After that the inherent ability of that weapon to shoot consistantly will put the rounds on the ground according to the PE or larger but not smaller....

If there needs to be more explanation I still have all the diagrams and the like to demonstrate..... They look like this,....

dispersion.jpg

Cheers,

Rob

Rob

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Rob,

Going back to your original figures, at 18,000 yards, 1 PE = 8 yds in deflection and 36 yds in range. Referring to your gunnery table excerpt, the figures given there show the errors (note plural) eD and eR at that range to be 8 PEd x 36 PEr. That gives 64 yds in deflection and 1296 in range. Thus 64 x 1296 = 82,944 square yards. That's the 100% zone for the gun. I think.

By contrast, in your # 28, you said

"Here is some data that I gained from a US manual...... at a range of 18000 yds the PE for a 240mm howitzer firing this particular ammo (HE...) is 36yds x8yds.....

What this means is that a single weapon firing a given (say 100 rounds for theory sake) mission that is perfectly laid will have a beaten zone that is 8 x 36 = 288yds deep and 8 x8yds = 64 Yds wide....."

Either I'm not properly interpreting the gunnery table, or your figures are off because you misinterpreted the table. Which is it?

I understand what you're saying about accuracy vs consistency, also the difference between the DMPI and the MPI. Further, I understand the object of the game is to get the MPI on the DMPI.

The key question for this part of the discussion is: "Whose interpretation of the gunnery table is correct? The difference is considerable.

Turning now to the intended target issue, I believe it safe to assert the targets wasn't a pillbox holding a squad, but a fortress like Katzenkopf, an altogether different matter entirely.

http://www.westwallmuseum-irrel.de/en/the-history.html

http://translate.google.com/translate?hl=en&sl=de&u=http://www.deutschesatlantikwallarchiv.de/westwall/b_werke/b_werke.htm&prev=/search%3Fq%3Dkatzenkopf%2Bb-werke%26client%3Dsafari%26rls%3Den

Am still looking for overall dimensions, but this, with 44 rooms and three floors, strikes me as the kind of target super heavy artillery is needed to smash, rather like what "Big Bertha" did to the Belgian forts at Liege.

Some plan and elevation dimensions here on Axis History Forum. Now that I can see Katzenkopf in cutaway from the side, it's clear super heavy artillery is the only viable tube artillery solution. Of course, when the 240 was being designed, neither the Tall Boy nor the Grand Slam existed, so it was effectively immune to most air attacks!

http://forum.axishistory.com/viewtopic.php?f=70&t=195768

Wicky,

How sad that yet again you have nothing to use but argumentum ad hominem against me. Nice of you to publicly announce the weakness of your position!

Regards,

John Kettler

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Either I'm not properly interpreting the gunnery table, or your figures are off because you misinterpreted the table. Which is it?

The key question for this part of the discussion is: "Whose interpretation of the gunnery table is correct? The difference is considerable.

The best rule of thumb to use in such discussions is "not Kettler" ;)

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Search for John Kettler and Panzers on Mars, nazi UFOs with underslung panther turrets, and V2 rockets from silos smaller than the missile itself and other kettlerian hokum completely lacking veracity that he has inflicted on the forum...

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There are a certain few who seem to feel driving Kettler from these forums is a worthwhile endeavour. However the majority of what he adds to these forums is actually of value and very few other people research as exhaustively. You of course, as with any posters contribution here, feel that somethings should be taken with a pinch of salt.*

So there you go. Enjoy the forums there is loads of info. And do not forget the search function for the archives as a lot of historic info was first discussed in the CMx1 forums.

* if you are non-native English "a pinch of salt" means evaluate as to true worth/treat with caution. It helps sometimes to know where people are from so you avoid the error of believing colloquial English will be understood. JonS is incidentally nowhere near Venus but actually in New Zealand.

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Wicky,

I think you're being abusive in that you know full well Steve's asked me not to bring up such matters, and I haven't. You, though, insist on doing so, and I'm quite tired of it. Please take your churlish behavior elsewhere, for it's most assuredly not needed here! The rest of us will go back to discussing the 240mm Howitzer M1.

Bulletpoint,

If you'd like to know what he's on about, with proper context and sans preemptive character assassination, please PM me.

Regards,

John Kettler

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