"Mortar rounds into rubble - how much cover?" Topic

I was wondering how much cover rubble provides from mortar fire, following a recent game of BA.. By "rubble" I mean concrete, stones and heavy brickwork.

My hazy memory of Monte Cassino is that rubble provides pretty good protection. BuT other people were arguing about air bursts and whatnot, with rubble having no good overhead protection. Were air bursts a 'thing' in WW2?

Yes, airbursts were a "thing" in WW2, but only for artillery rounds if I'm not mistaken. I don't think mortar shells had that capability.

Airbursts were also used extensively with heavier anti-aircraft artillery.

Jim

Only the US Army had artillery using the proximity fuse and only late in the war. The technology of the time did not allow the fuse to be used in a round as small as a mortar.

The Pentagon refused to allow the Allied field artillery use of the fuzes in 1944, although the United States Navy fired proximity-fuzed anti-aircraft shells during the July 1943 invasion of Sicily. After General Dwight D. Eisenhower demanded he be allowed to use the fuzes, 200,000 shells with VT fuzes or (code named "POZIT" were used in the Battle of the Bulge in December 1944. They made the Allied heavy artillery far more devastating, as all the shells now exploded just before hitting the ground.[36] The Germans felt safe from timed fire because they thought that the bad weather would prevent accurate observation. The effectiveness of the new VT fuzed shells exploding in mid-air, on exposed personnel, caused a minor mutiny when German soldiers started refusing orders to move out of their bunkers during an artillery attack. U.S. General George S. Patton said that the introduction of the proximity fuze required a full revision of the tactics of land warfare.

See Rick Atkinson (2013). The Guns at Last Light: The War in Western Europe, 1944-1945. pp. 460–62, 763–64

To be clear, you can have airburst without the proximity fuse: it's just a lot easier and more reliable with. But I'm with Col Campbell: I never heard of it from Mortars. You want proper artillery.

The germans had a "bouncing" mortar round which gave a sort of air burst. Not very common though.

Isn't there American Army or Marine manuals that have figured out how much cover is need for artillery?

Ruin rubble would have less overhead protection – collapased roofs and upper floors missing – but cellars would still exist (assuming apetures aren't blocked)and there are often small pockets of cover such as a section of roof lying intact at an angle. An artillery round or mortar coming in would be much the same – hitting rubble and sending a fair lot of it around the place, adding to the splinters (and adding a lot of dust). Instead of smacking into roofs they'd be inpacting at ground level so would have much the same effect as a normal ground impact for troops behind a field wall boundary, for instance.

The prox-fused ammo was allowed for naval AA since the rounds ended up in the sea if they failed and could not be recovered. On land they were very keen to retain the secret, as mentioned above. One wonders what effect VT shells might have had in the Bocage, at Metz and so on…

Some Nebelwerfer rounds had long snouts, I believe, to detonate a couple of feet above ground. Ditto some Ju87 bombs later on.

I have heard the 'rubble gives even better cover' thing too..but never any explanation.

I hypothesize the following.

1] Collapsed buildings don't collapse again.

2] It is harder to spot defenders in rubble as there are unlimited places to hide.

3] There are numerous foxhole like nooks and crannies to hide in.

4] Attackers cannot advance thru rubble easily and combined arms is much harder to coordinate.

That's all for now. Anybody got any input or comments on this? Sorry it's slightly off topic.

BuT other people were arguing about air bursts and whatnot, with rubble having no good overhead protection

For gaming purposes rubble still will give you a cover bonus of some sort. As it does in the RW. As others pointed out here. It is better than being in the open when receiving incoming fire of any type. Regardless of airbursts, etc. Yes, e.g. in WWII, the Germans at Monte Cassino, as pointed out …

So IMO short answer … "those other people" are "misinformed" … See what Blutarski, Wolfhag, badger22, etc., have posted here … TMP link

to detonate a couple of feet above ground. Ditto some Ju87 bombs later on.

Yes they had a long "probe" at the top of the bomb/shell, etc. so it blew up above ground.

See WO 291/138 Influence of ground cover on performance of HE projectiles.

Rubble (and strewn boulders) have a cover factor of V, the best. This reduces the lethal area of 25pdr rounds by a factor of ten and 3" mortar rounds by a factor of four.

No idea why it affects artillery more, I wasn't there when they conducted the firing trials. It means rubble has a similar protective value to slit trenches.

There was reference in another study to 3" 'jumping' mortar bombs, so maybe the British had those types of fuses too. I wouldn't overestimate the effectiveness of airbursts. Very hard to range in.

One of the first things you learn as an Infantryman. If to Try to get something solid between you and all the flying objects on a battlefield.
E.g. yes, a slit trench is better than nothing …

I wouldn't overestimate the effectiveness of airbursts.

Agreed … Again everything comes down to terrain and situation …

Artillery impact at an acute angle…so lethal area is not circular unlike a mortars which is almost so. It obviously would depend on the range and type of gun, howitzers having higher trajectory etc.

This means, if some rubble is between you and the impact it will give protection while for mortars less so. This is how I can rationalise the lesser reduction of a mortar's lethal range. There is more chance of the mortar coming down at nearly 90 degrees and landing near enough to kill.

Sorry if I'm not explaining this clearly – I need a diagram really!

Yes, but regardless … getting in/behind something solid increases your survivability. No matter what is being fired at you. Unless it's a direct hit and a big enough round/shell. Or a Nuc of course …

Wow, I can't believe no one has posted to play CoC instead.

I've read quite a few accounts of mortar rounds dropping into foxholes, so while rubble might offer some protection against misses, it's just as likely one could come right down into the nook you're hiding in…

Mortars are incredibly lethal weapons.

The rate of fire can be very high [ammo supply if portaged being the main limit on this]. If you have the ammo and have zeroed in the target a crew can put 10-15 bombs in the air before the first lands then have the tube disassembled and relocated before return fire arrives. [modern radar guided counter battery fire has changed this however].

The high trajectory allows them to get over obstacles and into trenches and gun pits.

They are relatively silent – so you get no warning of incoming rounds.

The shell/bomb walls can be thinner so you get more 'bang' for the same calibre/weight.

Many rules just give them a factor based on calibre and leave it at that. I believe the 25 pounder had a claibre of 88mm and the 3" mortar 81mm [not 75mm as 3" would be]. They should however have significantly different effects in game terms – IMO anyway.

Yes I like details. Not all details are equal and artillery is often abstracted in games to leave time for more tank details. At the end of the day it's up to the designers and players to make their own choices.

I've read quite a few accounts of mortar rounds dropping into foxholes, so while rubble might offer some protection against misses, it's just as likely one could come right down into the nook you're hiding in…

A direct hit on any position or even some AFVs would do damage. But it always does not occur, obviously. Even if you fire directly[i.e. you can see the target] using "open sights" IIRC it was called for a mortar.

Mortars are incredibly lethal weapons.
The rate of fire can be very high [ammo supply if portaged being the main limit on this]. If you have the ammo and have zeroed in the target a crew can put 10-15 bombs in the air before the first lands then have the tube disassembled and relocated before return fire arrives. [modern radar guided counter battery fire has changed this however].
The high trajectory allows them to get over obstacles and into trenches and gun pits.
They are relatively silent – so you get no warning of incoming rounds.
The shell/bomb walls can be thinner so you get more 'bang' for the same calibre/weight.

All true … I was an 81mm Mortar PL in the 101 for a bit in the early '80s. They could get pretty accurate with them. But generally mortars and FA are area affect weapons. Of course it's better to have some cover than be in the open. But there are no guarantees … you just are "Padding your Bets" … trying to get any type of cover between you and the incoming …

I would still opt for rubble – as any shot not directly on target is likely to be at least partially shielded by the rubble

Yep ! That is basically what I was saying … Better than no cover !

I have heard the 'rubble gives even better cover' thing too..but never any explanation.

I hypothesize the following.

1] Collapsed buildings don't collapse again.

2] It is harder to spot defenders in rubble as there are unlimited places to hide.

3] There are numerous foxhole like nooks and crannies to hide in.

4] Attackers cannot advance thru rubble easily and combined arms is much harder to coordinate.

That's all for now. Anybody got any input or comments on this? Sorry it's slightly off topic.

I've read more or less similar things from some memoirs or from Roland Bartetzko and others various veterans over on Quora.

Urban rubble/ruins (especially modern steel & reinforced concrete buildings) create myriad locations of useful cover and concealment for defenders, create open fields of fire on what open avenues of approach remain, and provide ready-made obstacles for attackers.

Intact buildings require preparation (if time allows) to be more useful as a fighting position, or so I've read.

To be clear, you can have airburst without the proximity fuse: it's just a lot easier and more reliable with.

Yep, just need a time fuze and a precisely-known time-of-flight.

Say, a large-caliber AA gun.

Urban rubble/ruins (especially modern steel & reinforced concrete buildings) create myriad locations of useful cover and concealment for defenders, create open fields of fire on what open avenues of approach remain, and provide ready-made obstacles for attackers.

Yes very much so. Again e.g. the Germans at Monte Cassino …

Intact buildings require preparation (if time allows) to be more useful as a fighting position, or so I've read.

Yes and having the time is a big factor.

Again note: e.g. a .50cal will chew thru bricks like me and box of peanut brittle ..