"Effect of a large caliber HE hit on those inside a bunker?" Topic

Something I've heard various vague mentions to is about the effects of a non-penetrating large caliber (105mm, 155mm+) non-penetrating HE hit on a concrete bunker on the crew inside it. (Or I suppose a very near miss by 5" to 8"+ naval shells) I suspect it's in the "not good" category?
Thanks.

Non-penetrating shouldn't be too bad or the army wouldn't shell their own people in bunkers to give them some experience of what to expect.

Obviously, non-penetrating is what every occupant is counting on, but depending on the circumstances (shell size, quality of the bunker, etc), the greatest effect might range from psychological to concussion.

The former might keep occupants from coming out in a timely manner (and generally add to the burden of combat as long term effects), and the latter might render them hors de combat in for a longer term.

The countless cases of men going mad under prolonged bombardment, even if theoretically safe from direct hits on their cover, clearly suggest that mere physical survival is not necessarily enough to declare a such as "ineffective."

Twin Farthings,

TVAG

I would think the overpressure effect inside a bunker would be minimal as it would be dispersed outside of the structure. Noise and vibration could be considerable though IMO.

The effects can be classified as "not good"! Ask any veteran who has endured this.

I have been in a 'Bombard OP Bunker' with solid steel doors and armoured windows used to give troops the experience of being under fire. Even though the calibre of artillery used and the angle the shells came in at guaranteed safety, the level of nervousness amongst the personnel was palpable. Having also actually been caught in the open by enemy artillery, I can witness that, to some extent, the anticipation in the bunker was almost worse for morale. Either way, that latter aspect seemed to be the most important.

A really well constructed bunker with blast proof doors ought to be more scary than dangerous.
Less well constructed ones are more likely to fall in the not good category.
Blast next to any sort of opening is going to be really unfun.

I remember reading a story in a book about the Vietnamese Independance war : some French soldiers were in a bunker, about to be stormed by a numerically crushing Vietnamese force. They were still in contact with the rear, since the Vietminh had failed to locate and cut the telephone link. They requested a ToT mission as the Vietminhs were swarminfg the roof of thye bunker. It was a slaughter, the Vietnamese were butchered, and the French had no losses in side the bunker. So, I'll say, you can take some hits inside a bunker, even a less solid one, as what you had then in Indochina was not Maginot line standards…

My father was during the German occupation (in 1943) called up for the "Arbeidseinsatz" (young males in the occupied territories were forced to work in Germany). He was a housepainter. He told me later that he was painting various cable pipelines (each a different colour) in the cellar of a brand new hospital when the sirens for another airraid went off. Since he already was in a cellar and had not finished the painting he stayed there but others passed him to the airraid shelter deeper in the building. When "all clear" sounded, those who had been going to the end of the shelter were all dead though the blast. When he left the shelter the hospital was completely gone.

So, perhaps the shelter was not really well constructed ? I don't remember him telling about blast doors.

You know, if someone told me "you have the word of the United States Army that what you're about to experience is perfectly safe" I think I could about guarantee that I would show the symptoms of severe stress.

But I concur. Brief and non-penetrating should be OK. Prolonged is why they used to call it shell shock. Also worth remembering that not all contractors build to specifications, conscript labor can't be trusted to have your interests at heart and there are always freak shots impacting where you'd swear they couldn't reach.

Agree that while it would likely protect the occupants, likely is not a guarantee and a prolonged bombardment would have some effects that were not purely physical

I read that they used M12's (155mm Howitzers) in direct fire mode on bunkers in the Siegfried Line during WW2. One hit rung their bell so bad the enemy were physically incapable of fighting.

I think that in the end there are so many variables that it is difficult to come up with hard and fast rules. What is the quality of the garrison and its experiences? Who built the fortification? (Remember in WW2, Resistance workers put sugar in the concrete for Atlantic Wall fortifications weakening it substantially.) What is being used to attack the fortification? An M12 or a Panzerfaust? and so on.

I have seen troops out in the open suffer 155mm artillery fire with no casualties while a lucky strike from a 81mm mortar has taken out a well constructed bunker.

It's the opposite of large caliber, but once had a battalion fire direction center set up in a concrete bunker at OP13 at Bragg, overlooking an impact area where infantry were supposed to maneuver with supporting fires (60mm/81mm//105mm/155mm and helo support). We were there to coordinate and oversee the fire support portion of the operation, and at one point, with a 105/155mm prep in full swing on the "objective," went up on the bunker roof with my boss to get a better view of the fall of shot. As the infantry started to maneuver, we lifted and shifted the heavier stuff back, and put 81mm/60mm fire onto the objective. After a couple of minutes, went back up onto the roof, and to our surprise, found a small, smoking crater and some 60mm spall. Nobody saw, heard, or felt the impact- including people in the vehicles parked on the back side of the bunker, a couple of hundred yards back.

I remember reading somewhere that the Germans had erected impromptu fortifications in a German city in 1945. They had done a very good job, and all efforts to root them out had failed.

The US commander had a Long Tom brought up to fire down a long avenue at a particularly stout building.

After 1 shot,the white bed sheets started flying. The town commander observed that, if the US was prepared to use 155s in direct fire mode, it was time to start thinking about another line of work.

Big Bunkers may have has blast walls internally.You have to laugh at some of the little brick 'Pillboxes', we Brits put up… mainly for LDV. Would not have lasted long!

Those pillboxes near where I live are concrete. It's not exactly obvious now why they were built there at all.

In those dark days of 1940, I guess something quick looked a lot better than running the risk it was still a building site when those Jerry paratroopers arrived.

As I recall reading, the US assault on the Siegfried Line involved bring up some REALLY BIG corps level self-propelled artillery to engage German bunkers by direct fire.

B

Very few survivors were mainly concrete. There were more, when young. Not many left. Most Tank obstacles have also gone. To be honest… can only think of One Pillbox… rural…and why built there? Not a landing ground!

Stop lines, Heedless. If I remember correctly there were three or four between Kentish beaches and London. If you put everything in one line--well, you're trusting the other guy not be break through anywhere. I suspect they had (or would have had) psychological value for the defenders, too. You really would be, as the old joke has it, "redeploying to a previously prepared position." It tells the troops exactly where to stop, and does the same for reinforcements and resupply.

As noted, while a huge shell may not kill everyone in the bunker, they ain't happy!

I have a friend that was in Ukraine holed up in a large factory with 12-16 inch thick reinforced concrete walls. A 152mm hit was barely noticed but he could feel the heat of the explosion coming through the concrete. They were taking indirect fire with random hits, not direct fire into the same spot.

Most of the time they were hunkered down in the basement being completely protected.

This is from a US Army Terminal Ballistics test as to how many hits are needed to penetrate:

Wolfhag

There are stop lines north of London too and many of the boxes can still be seen. There are lots of them still there in an east-west line near Watford, for example. There is one under Bushey railway arches disguised as an arch, another disguised as part of a school (https://edob.mattaldred.com/map/S0000549), and more further east on the banks of the Colne, in farmers' fields.

I used to play in one of the latter as a kid – this one

link

It was keyhole shaped in plan view with an entrance in the upright. Inside you could walk around the round bit and there was hatchway access into the middle enclosure, where there stood an empty pintle. It would have mounted a Lewis gun or Blacker Bombard probably.

I used to hang out there with my dog (RIP, Angus, my good friend) on dull rainy days in the school holidays. There's a steel plate blocking the entrance now, so you can no longer get in. AIUI farmers were given £5.00 GBP after the war towards the cost of knocking them down, but if they weren't really creating any problems (because you used the field for grazing for example), the farmer often spent the money on something else and left the pillbox there.

They were often brick-faced but concrete inside, so while looking innocent they'd probably stop a bullet – if not a lot more.