mortars

[andhen2003]

I was recently reading an account that in WW2 the Americans had both light and heavy mortar shells for the same launcher. The heavies supposedly had the blast of a 105mm howitzer shell, while the lights could of course go much farther. I assume that CMAK models the "light" mortar shell since the blast doesn't look anything like a 105mm. I'm not sure what size mortar shell the article discussed but it looked like an 80mm. Did other armies have similar differented shells for their mortars? Am I correct in assuming CM models the standard light shell? On a related matter, is it worthwhile firing 80+mm mortars at troops in light buildings? I've certainly seen drmatizations of it occuring (Band of Brothers for example) when they fire at the sniper in the farmhouse, but it doesn't seem practical in CM.

[PiggDogg]

Please provide the citation and link for this above noted information. Such would be illuminating and informative.

Cheers, Richard

[ April 21, 2005, 09:38 AM: Message edited by: PiggDogg ]

[andhen2003]

Actually Im pretty sure I read it in an Osprey book that I was looking through while in the bookstore. Unfortunately didn't end up buying but picked up a book on the US Civil War instead!

[Michael Emrys]

Ack! What a waste!

Michael

[PiggDogg]

Generally, in CM, if one has a number (at least 3 or 4) of on-map 81/82 mortars and they fire at enemy infantry in a small wooden building, the building will probably be toast within one minute. If these mortars do the same against an enemy in a small heavy/stone building, the building will possibly become toast after one minute.

In all cases, even those described hereinafter, the objective is to toast the building within one minute so that the enemy in the building can't easily escape the building before it collapses. If the infantry is in any building when the building collapses, the infantry will suffer substantial casualties and possible elimination, especially if they are on upper floors during the collapse.

If two or more 81/82 FOs (the more the better) target a small wooden building and the barrages start at the beginning of a minute turn, the small wooden building is probably toast within one minute. Regarding a small stone/heavey building in the same situation, the small stone/heavy building will probably last through one minute, but will be substantially damaged.

Of course, while under barrage from two or more 81/82 FOs, infantry attempting escape from buildings or any terrain will suffer from the barrage while escaping.

Regarding large wooden and large stone/heavy buildings, they take much more damage than their smaller counterparts.

In order for these large buildings to be destroyed within one turn by 81/82 mortars, more than 3 or 4 on-map 81/82s and more than 2 81/82 FOs will be required.

Generally, unless a large building is already substantially damaged, I would not waste 81/82 mortars (on-map or FOs) on large buildings. They are too hard to kill with such weak HE. Six to eight (preferably 8 or more) direct fire 75/76 HE throwers will toast even a large stone/heavy building within one turn.

If there are direct fire, enemy vehicle HE thowers around, I generally don't set up on second floors of buildings. The risk is too great for death within one turn due to collapsing building parts.

Regarding the attack on Foy in the fine series Band Of Brothers, it seemed that those US 60mm mortars targeted that building overly quickly and the explosions (if I remember correctly and if I am correct) seemed like 105 sized explosions.

A bit earlier in that series, when E Company was under barrage in the forest outside Foy, the replication of that barrage seemed to be a superb and seemingly accurate representation of an 81 mm mortar barrage into woods. Those scenes (amongst a plethora of other seeming most accurate battle scenes in BOB) seemed to be some of the most accurate and most infrequently viewed battle scenes in war movies.

Cheers, Richard

[ April 21, 2005, 11:59 AM: Message edited by: PiggDogg ]

[John D Salt]

Originally posted by andhen2003:

I was recently reading an account that in WW2 the Americans had both light and heavy mortar shells for the same launcher. The heavies supposedly had the blast of a 105mm howitzer shell, while the lights could of course go much farther. I assume that CMAK models the "light" mortar shell since the blast doesn't look anything like a 105mm. I'm not sure what size mortar shell the article discussed but it looked like an 80mm.

You're right. Ian Hogg's "Encyclopedia of Infantry Weapons of World War II" says that the US 81mm mortar M1 originally issued with the light M43 bomb and heavy M45 bomb. The latter had super-calibre fins which were held under tension by soft rivets and sprung out when the bomb was fired. While this provided good stability, unfortunately the fins lost their tension in storage, so this bomb was withdrawn in March 1940, and replaced by the M36 (or possibly M56, but I think this is a typo). According to Hogg the M43 weighs 6.87lb and ranges to 3290 yds, the M36, 10.62lb and 3290 yds.

Originally posted by andhen2003:

Did other armies have similar differented shells for their mortars?

The British 3-inch (81mm) mortar was issued with 10lb and 7.5 lb bombs, but I'm not aware what difference this made to range, and the effect of both types of bomb was similar, thanks to the improved fragmentation of the lighter bomb.

All the best,

John.

[Wartgamer]

The Germans also had a 81mm heavy

[JonS]

not a mtr, but the British 4.5-in (or was it the 5.5-in.?) had an 80lb and a 100lb round.

[flamingknives]

5.5", apparently.

[Wartgamer]

The German heavy 81mm round.

At 16.5 pounds, this probably had a much shorter range than the typical WGR39 round (7.7 pounds).

The US heavy round had very thin walls and was noted for its inferior fragmentation compared to teh standard US 81mm HE round. It was basically good for penetrating roofs on delay fuse settings.

The German 120mm round seemed to come in different HE weights also.

[ April 21, 2005, 04:09 PM: Message edited by: Wartgamer ]

[Wartgamer]

Regarding the attack on Foy in the fine series Band Of Brothers, it seemed that those US 60mm mortars targeted that building overly quickly and the explosions (if I remember correctly and if I am correct) seemed like 105 sized explosions.

A bit earlier in that series, when E Company was under barrage in the forest outside Foy, the replication of that barrage seemed to be a superb and seemingly accurate representation of an 81 mm mortar barrage into woods. Those scenes (amongst a plethora of other seeming most accurate battle scenes in BOB) seemed to be some of the most accurate and most infrequently viewed battle scenes in war movies.

It was a very good representation of indirect fire but certainly not light 81mm rounds. Trees were being knocked down left and right.

I just watched 'Windtalkers' (ugh) and its comical the way they use gasoline or other flammables to represent arty. In one scene a bazooka makes half a hill go up in flames.

The Germans were known to mix in all types of indirect fire. Accounts of Nebelwerfers, mortars and true artillery rounds being used together during a barrage is common.

[JasonC]

Yes they had two standard shell weights, for the 81mm. The light was more common, for range. The BoB weapons in the forest are 105s, not mortars. The US mortars that hit the MG in the building are company 60s, not 81s.

As for the comparison between mortar shells and tube arty shells, the first thing to understand is that mortar shells carry more HE as a portion of their weight, than tube arty shells. The shell body does not need to withstand such high forces, so the walls can be thinner. Mortar shells also typically impact more nearly vertically. Both of these things mean, for the same weight of shell, a mortar round produces more fragmentation than the same weight of tube arty shell.

The comparison of 81s with 105s is casualty radius, the range at which a man standing upright has a 50% chance of being hit by fragments. It is comparable for the two rounds. Inside that radius, the 105 is going to do more, since it carries more HE. Which matters if the targets are under cover, rather than upright - all hits need to be nearer to do something in that case. In practice, the standing man ranges only matter for the first few rounds, as everyone gets to ground. Which drops exposure by a factor of 10.

Are CM medium mortars underpowered in blast effect, compared to 105s? Yes. The 81s aren't as nasty in CM as they were in real life. The on map ones make up for it by putting about 1 out of 3 shells very close to the aim point, though. Which typically lets them pin or break anything they fire at for a full minute (-1 man and pinned is about the best the target can hope for, and -1 or -2 men and broken is quite common). But this refers to their use individually against a point target. In CM, that is what they do best - their barrage ability is minimal.

If you want a real mortar barrage, buy a medium module as an FO. 120s as Russians or Germans e.g. You should understand that CM has somewhat skew arty effectiveness compared to reality. The light calibers are underpowered when used indirect, the heaviest calibers are overpowered. 150mm plus arty is godlike in CM. Also, CMs way of calculating blast is overly sensitive to exact placement, which favors on map guns and especially the flat trajectory direct fire stuff.

Flat trajectory 150mm stuff is way overmodeled. Part of the reason is, they track shell placement down to 2m, when "squads" aren't actually that small. You can't put a 150mm shell on top of a squad in reality - the squad is a dozen guys well spread, so wherever you put the shell you are on top of 1-2 men mebe, but not right on top of all 10. Of course it is not pleasant just being 15m from a 150. But the game rewards placing it at 2-4m rather than 15m, when the thing it is being placed next to is too big for that to really matter.

Some players ban on-map 150mm weapons as unrealistic etc. I recommend it. Some also restrict calibers larger than 155mm as off map guns. I recommend that too.

As for the mortars, just understand they will do their job against point targets. The undermodeling of small blast is made up for, by the overmodeling of exact shell placement. Woods foxhole MGs (because of treebursts, which are modeled and nasty) and anything in trenches (because few other things work on them, and exact placement works against them) and especially on-map guns, are their primary targets.

To deal with infantry in a building, direct fire HE is the best weapon. The effect differs dramatically based on whether the shell hits the building or lands outside. Flat trajectory stuff hits the building. Any 75mm weapon firing direct will clobber a unit in a building on one turn. The effect is roughly 3 times what a mortar will do in the same circumstances, because practically every shell hits.

As for US 60mm mortars, their main CM advantage is medium speed, which lets them keep up with ordinary infantry, using "move". They hit harder than Russian 50mm (which try to make up for a weak round with a large ammo load), not nearly as hard as the 81s. 2 of them firing at the same target for 1 minute will still pin it, and often KO a gun. Which is what you need from on map mortars in CM.

I hope this helps.

[Wartgamer]

One of the advantages of mortars fired indirect is the accuracy (range or length) compared to tube artillery.

Most people think of mortars as being inaccurate. They are susceptible to wind forces but are actually a much better support weapon for neutralizing (pinning) enemy forces.

In Normandy, tube artillery was just too 'loose' as far as getting the range down. This is because the large spread of rounds along the length of travel of the guns. If firing over your own troops heads, you would want them to be back at least 200 yards or so. In the bocage, troops were seperated by half that distance or less. Also, the artillery would not be able to use low angle fire since it must clear the hedgerow of your own troops.

German mortars were said to account for 70% of the casualties in the bocage. Part of this stat is that mortars can fire over the hedgerows and defeat the embankment cover that artillery could not.

I am not sure how CM models indirect fire spread or differentiates it for different weapon systems.

[Wartgamer]

Data on US mortar rounds from Korean War website...

General Data

Weight: 136 lbs assembled; tube 44.5 lbs; mount 46.5 lbs; base plate 45 lbs.

Overall Length: 3 ft 9.5 in.

Muzzle velocity (HE): 700 f.p.s.

Rate of Fire: 18 rounds/min norm; 30-35 rpm max

Maximum Range (HE): 3290 yds

Sight: M4

Ammunition:

M43A1 Light HE: 6.87 lbs; range min 200 yds; range max 3290; 80% frag radius 25 yds (comparing favorably with 75mm howitzer); fast detonating fuse (explode on surface).

M45, M45B1 Heavy HE: 10.62 lbs; range max 2558 yds; bursting radius comparable with 105mm howitzer; equipped with delay fuse so some penetration possible for demolition use.

M56 Heavy HE: 15.01 lbs; range max 1300 yards; adjustable fuse for quick or delay operation.

M57 WP (White Phosphorus): 10.74 lbs; range max 2470 yds; designed to lay down screening smoke, but had definite anti-personnel and incendiary applications.

M57 FS: 10.74 lbs, range max 2470 yds; laid down dense white smoke.

M301 Illuminating shell: range max 2200 yds; attached to parachute; burned brightly (275,000 candlepower) for about 60 seconds, illuminating an area of about 150 yards diameter; used M84 time fuse, adjustable from 5 to 25 seconds before priming charge detonated, releasing the illum and chute.

This website shows a crew firing 81mm and using heavy bombs.

http://www.olive-drab.com/od_infweapons_mortars_81mm.php

This website shows the very heavy M56 round for the US 81mm. Very close to the German Heavy 81mm mortar round in shape/weight

http://www.inert-ord.net/usa03a/usa5/6081/60mm.html

[ April 22, 2005, 11:07 AM: Message edited by: Wartgamer ]