TOT arty fires

[John D Salt]

Originally posted by jtcm:

John D Salt:

I'd never paused to reflect that the "not the scratch upon them" stories might be wistful tall tales rather than real anecdotes. Paul Fussell writes that he did see a German squad dead in their positions; that they might have been killed by a TOT is his speculation.

I thought pressure waves from HE blasts killed by rupturing internal organs; but freely, and thankfully, admit that I know little on the subject.

You are quite right in thinking that the principle direct injury-causing mechanism of blast is damage to internal organs -- ears first, then lungs and intestines. Such wounding mechanisms may be evident in the cases of large explosive charges with great blast effects and relatively little fragmentation.

However, to give an idea of how relatively tough human targets are against blast damage, here are a couple of tables (which should not be taken as gospel, given that peak overpressure is by no means a perfect indicator of effect) showing the likely effects of different levels of blast:

Overpressure (mbar) Damage

1-3___________Minimum damage to glass panels

10-15_________Typical window glass breakage

15-25_________Overpressure at limit for debris and missile damage

35-75_________Windows shattered, plaster cracked, minor damage to some buildings

70-100________Personnel knocked down

75-125________Panels of sheet metal buckled

75-150________Failure of wooded asbestos panels for conventional homes

125-200_______Failure of walls constructed of concrete blocks or cinder blocks

200-300_______Self-framing paneled buildings collapse

200-300_______Oil storage tanks ruptured

300-500_______Utility poles broken off

300-500_______Serious damage to buildings with structural steel framework

350-1000______Eardrum rupture

400-600_______Reinforced concrete structures severely damaged

400-600_______Railroad cars overturned

700-800_______Probable total destruction of most buildings

2000-5000_____Lung damage

7000-15000____Lethality

20000-30000___Crater formation in average soil

Source: Andrew C. Victor, "Warhead performance calculations for threat hazard assessment",

1996 DDESB Explosives Safety Seminar, Las Vegas, Nevada, 20-22 Aug 1996, available at

http://members.aol.com/Andrewvict/WRHDPRFM.pdf

Overpressure (p.s.i) Damage

5_____________Possible tympanic membrane rupture

15____________50% incidence of tympanic membrane rupture

30____________Possible lung injury

40____________Concrete shatters

75____________50% incidence of lung injury

100___________Possible fatal injuries

200___________Death more likely than not

Source: Nick Colovos, "Blast Injuries", available at

http://mediccom.org/public/tadmat/training/NDMS/Blast_Document.pdf

The difference between the overpressures required to produce missile damage (15-25 mbar, and down to 10 mbar for flying glass) and the minimum to burst eardrums (350 mbar) should make it quite clear how much more hazardous fragements are than blast.

Even for a pure-blast detonation of bulk explosive, secondary fragmentation (concrete buildings collapsing at 125-200 mbar) is obviously going to be a much greater hazard than the direct effects of blast (7000 mbar the lower limit for lethality). If, as is invariably the case with field artillery, the explosive is surrounded by a fragmenting steel shell, the difference will be greater still. An OR textbook I have containing a problem on the assessment of artillery shell effectiveness considers fragmentation only, and completely neglects blast effects.

Basically, if you are close enough to the bang for blast to worry you, it's a knocking bet that the fragments will already have killed you quite badly.

[Edited to add some example distances]

Reading by eye from a table in Victor's paper, the scale distances for peak overpressures (recalling the caution that this alone is not an ideal dmaage predictor) of 200 psi (death more likely than not) and 100 psi (possible fatal injuries) occur at 2 and 3 scale ft/lb^-3 respectively.

Therefore, killing distances of primary blast effects for different sizes of bulk TNT are (200 p.s.i. distance first, 100 p.s.i. distance second) would be something like:

1lb________2-3ft

8lb________4-6ft

27lb_______6-9ft

64lb_______8-12ft

125lb_____10-15ft

216lb_____12-18ft

343lb_____14-21ft

512lb_____16-24ft

729lb_____18-27ft

1000lb____20-30ft

Apologies for the eccentric units used, but they are what is used in the sources and I'm too lazy to convert them to SI units. Anyone with access to a calculator can extend the table as desired in whatever units they fancy.

As has already been pointed out, the HE content of field artillery shells is only a few pounds. There may be minor corrections to be made for fillings with more or less brisance than TNT, but the method is already so rough that these won't matter. However, the order of magnitude of the effects under discussion should be evident.

All the best,

John.

[ April 10, 2005, 04:04 AM: Message edited by: John D Salt ]

[Wartgamer]

Some reality first:

The US 105mm HE is 4.9 pounds. The 4.2" mortar had 8 pounds. The US 155mm HE is 15 pounds. The US 8 inch is 37 pounds.

These are probably the most common weapons that make up a US TOT but I have read that 240mm were also used. Obviously, they could not get into each shoot because of slow loading times.

The primary CW field piece is a 25 pounder with LESS than 2 pounds of HE. More than likely this was the reason the CW did not like to use TOT.

[ April 09, 2005, 05:18 PM: Message edited by: Wartgamer ]

[JonS]

Originally posted by Wartgamer:

Some reality first:

The US 105mm HE is 4.9 pounds. The 4.2" mortar had 8 pounds. The US 155mm HE is 15 pounds. The US 8 inch is 37 pounds.

Oh - good point. That raises FKs distance to 17mm for the 8-in. That'll make a difference

These are probably the most common weapons that make up a US TOT but I have read that 240mm were also used. Obviously, they could not get into each shoot because of slow loading times.

Roger Irrelevant.

[ April 10, 2005, 12:44 AM: Message edited by: JonS ]

[JonS]

Originally posted by Wartgamer:

The primary CW field piece is a 25 pounder with LESS than 2 pounds of HE. More than likely this was the reason the CW did not like to use TOT.

You dum fuk. I've already told you why the CW preferred not to use the TOT proceedure they had in place. Learn to read or stick your bull**** back where it belongs.

[Wartgamer]

Do facts generate profanity in CW wankers?

[Wartgamer]

Probable causative agent2 Head Neck Thorax Abdo-

men Upper extremity Lower extremity Upper half of body Lower half of body

Upper and lower halves of body

Pelvis Total

Casualties with single wounds

High explosive 61 1 31 6 3 7 4 5 9 2 129

According to this study of single cause KIA's, the head is the most likely area to be vulnerable to HE. Its about 50% followed by the Thorax at 25%.

Notice that the neck is not a large contributor.

Mr. Salt seems to think that all HE blast effects pale in comparison to fragmentation. This is usually just the case for troops in the open. When under cover, blast can kill/wound troops that can not be hit with fragmentation.

[JonS]

Originally posted by Wartgamer:

Do facts generate profanity in CW wankers?

No. Boneheaded, lazy thinking, sanctimonious, previously banned, trolls do.

[ April 09, 2005, 05:54 PM: Message edited by: JonS ]

[JonS]

Originally posted by Wartgamer:

This is usually just the case for troops in the open. When under cover, blast can kill/wound troops that can not be hit with fragmentation.

LOL. I was waiting for this fallacy to rear it's head. You are right that blast has more effect against troops in confined spaces. However, 'troops in confined spaces' and 'simultaneous, combinatory blast fronts from TOTs' are mutually exclusive.

Dolt. Why don't you climb back up inside that bull.

[ April 10, 2005, 12:42 AM: Message edited by: JonS ]

[Wartgamer]

Do you need to drink much to be this abusive?

[JonS]

Do you need to drink much to be this stupid Roger?

[John D Salt]

Originally posted by Wartgamer:

Probable causative agent2 Head Neck Thorax Abdo-

men Upper extremity Lower extremity Upper half of body Lower half of body

Upper and lower halves of body

Pelvis Total

Casualties with single wounds

High explosive 61 1 31 6 3 7 4 5 9 2 129

I believe that your appallingly bad habit of regurgitating googled material shorn of context and without citation has been commented on before.

The material you are quoting comes from

http://history.amedd.army.mil/booksdocs/wwii/woundblstcs/chapter6.htm

Had you bothered to read it, you would have seen that all the cases in the table you partially reproduce are due to penetrating injuries by small-arms or fragments.

Originally posted by Wartgamer:

Mr. Salt seems to think that all HE blast effects pale in comparison to fragmentation.

And with excellent reason.

As can be readily ascertained by anyone who refers to the link given above and who is not too idle or incompetent to actually read the document, the table you allude to is based on a sample of 1,000 USA battle dead. Of these, 107 are attributed to small arms, and 876 to fragmentation injuries of various kinds. 4 are attributed to cremation in a tank, and 13 to blast injury.

That's 13 blast deaths to 876 caused by fragmentation, a ratio of better than 60 to 1. "Pale in comparison" seems a wholly accurate description of such a state of affairs, don't you think, Roger?

John.

[Wartgamer]

Ok, so let's see if a bit of linear scaling isn't worth a shot (I would go and get my notes for shockwave modelling, but can't be bothered right now)

A reasonably large city is 20km from centre to edge, so that's 20,000m with 20,000,000kg of TNT each. If we scale back to field artillery sizes (let's be generous and say 2 kg) the distance goes down to 2 mm. Of course, it might not be simple and linear but it gives an idea of the problems of applying a principal (even if it is correct) to a problem on a radically different scale.

This is absolute rubbish. It has nothing to do with the effect.

The basic effect is this. The effect was that 8 evenly spaced 20 kton nukes arranged around a target can achieve better blast effects than 1 megaton bomb. In other words, 160kton can make the same blast effects as a bomb 6.25 times its size.

Why you go off on some bad math calc is beyond me.

[flamingknives]

I appled the scaling to transfer the effect observed with atomic weapons down to sizes associated with field artillery. It's definately a quick and nasty calc, but an interesting one, IMHO.

The point is that, assuming blast magnitude is proportional to mass of TNT, being at a distance of 20km of a 20kT weapon will have the same blast effect as being at a distance of 2mm from a field artillery shell. Roughly.

Even with big shells and this combining effect, you still need shells landing within a half metre radius. In any case, I suspect that the blast of a 20kT weapon at 20km will not be fatal.

[Wartgamer]

Holy Cripes.

Why does it need to be fatal? I have already said numerous times that artillery is largely a wounding agent. Hence the low death rates associated with it. Everyone should appreciate that and do not need Mr. Salt to act like its a amazing discovery.

Artillery wounds mostly through fragmentation and blast effects. The blast itself or the secondary or tertiary effects of blast.

The blast can be directly additive for shells that explode simultaneously or near simultaneously. For those that explode in rapid succesion (blast waves do not interact but the soldier is thrown about by one after the other), the physical effects are like being in the center of several large brutes who 'bounce' you between them in a very short time span. Well within human reaction time (0.4 seconds).

For 10-20 battalion shoots, some shells in a converged artillery TOT strike WILL be additive in thier blast effects. The rapid assault on the eardrums (multiple fluctuations in a short span of time) are much more debilitating than one loud noise.

[flamingknives]

Fatal, significantly wounding, same same.

Will the amount of shells falling sufficiently close together to create a superposition of overpressure actually be significant as opposed to a regular barrage?

[Wartgamer]

My opinion is that if the shells can all be coincided such that they all fall within 0.4 secs (or very close to that time span), they are significantly a better payoff. They do not all have to physically combine waves. Human reaction time, being what it is, would not allow someone to take any cover. Its very much like being under a mortar barrage.

In a typical artillery barrage, the shells (unless directly coming at you) give some warning and protective measures acan be taken. Even if just laying flat on the ground. A TOT saturates the area and if you are within it, you will be within its effects before you can do anything.

[flamingknives]

Unfortunately, having an opinion on something doesn't make it so.

The surprise factor of a TOT shoot has been noted before and agreed upon. you've just got to wait 2 or 3 minutes more before you can hit what might be a fleeting target.

[John D Salt]

Originally posted by Wartgamer:

Holy Cripes.

Why does it need to be fatal?

Presumably you should know the answer to this, since it was you yourself, nobody else, who chose to use the figures from a survey 1000 battle fatalities. Don't whine at me because the figures you picked clearly show that you are talking total drivel.

Originally posted by Wartgamer:

I have already said numerous times that artillery is largely a wounding agent.

No ****, Sherlock. This astounding insight is on a par with the revelation you have just made in another thread that people who have just fired a bolt-action rifle need to operate the bolt before firing again. Truly, it's a remarkable mind you have there.

Originally posted by Wartgamer:

Hence the low death rates associated with it. Everyone should appreciate that and do not need Mr. Salt to act like its a amazing discovery.

You are the one who chose to look at figures for fatalities. If you wish to present any figures for non-fatal injuries, go right ahead -- and give an accurate citation to your source this time. Will you be able to find any source showing a high proportion of blast injuries due to field artillery? No, you won't because you are talking bull****.

As for my "acting like its a amazing discovery", the point would carry a tad more rhetorical force if I had ever done any such thing. As it is, I'm afraid it just makes you look like a lying twat.

Originally posted by Wartgamer:

Artillery wounds mostly through fragmentation and blast effects. The blast itself or the secondary or tertiary effects of blast.

HE rounds from field artillery wound mostly through fragmentation. Blast, flash burn and the inhalation of noxious fumes are all possible causes of injury, but they hardly matter by comparison with fragmentation.

I have on my desk a copy of FM 6-40, the US Department of the Army Field Manual on Field Artillery Gunnery, published January 1950.

Chapter 4, "Artillery Ammunition", goes into a good deal of detail on the fragmentation patterns of shells. The only mention of blast I can find is in paragragh 24, section c, part 4, which says in part:

"When penetration occurs and the shell is in the earth at the instant of detonation, the fragmentation effect above ground is very small. Penetration into a bunker or dugout will produce casualties by blast effect, suffocating gases, and fragmentation."

Apart from this special case, the effects of blast seem to be entirely neglected.

Chapter 19, "Miscellaneous Missions", contains a paragraph on TOT fire missions. The first section of this says, in part:

"Time-on-target (TOT) is a special technique of firing the pieces of several units so that the projectiles of all the units firing arrive at the target area at the same time. This technique results in placing a maximum number of rounds on a critical area in a minimum interval of time, thereby utilizing the full value of the element of surprise."

No mention is made anywhere of TOT shoots producing greater casualties by blast. What do you think the reason for this omission might be? Is it likely to be because you know more about field gunnery than the officers who prepared this manual?

Originally posted by Wartgamer:

The blast can be directly additive for shells that explode simultaneously or near simultaneously. For those that explode in rapid succesion (blast waves do not interact but the soldier is thrown about by one after the other), the physical effects are like being in the center of several large brutes who 'bounce' you between them in a very short time span. Well within human reaction time (0.4 seconds).

For 10-20 battalion shoots, some shells in a converged artillery TOT strike WILL be additive in thier blast effects. The rapid assault on the eardrums (multiple fluctuations in a short span of time) are much more debilitating than one loud noise.

Sheer and unadulterated bull**** of the most nostril-twitching pungency.

Instead of flapping your gums and repeating the same gormless drivel over and again, post a source that supports your remarkable assertions. Blast waves like being punched about by three bouncers, my old Aunt Fanny's philtrum.

Free clue: The reason you are experiencing such difficulty in finding supporting sources is because you are talking utter tommyrot.

Bull**** over, bull**** out.

John.

[flamingknives]

My God, John's gone nuts

[Wartgamer]

A foul mouthed nut also.

[flamingknives]

I'd say exasperated.

[Wartgamer]

Another effect is that shells landing in very close succesion may acually trigger a PD fuse off. So a round that lands/detonates may actually trigger another one still in the air through its blast/fragments/ejecta.

[JonS]

So, Roger, you'd know: how is the market for red herrings these days?

[Michael Dorosh]

So after Jon S, Andreas, Jason C, and John D. Salt abandon attempts at discussion with him, umm, how many grogs does he have to go through before he just goes away?

If it isn't obvious by now that he's

a) making this stuff up just to aggravate, or,

even more frighteningly, honestly convinced of what he's saying...

when will it be?

[Wartgamer]

Oh, before I forget, the very weak 25 pounder switched to a more powerful explosive late in the war in an attempt to increase its output to something more effective.