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Old 07-28-2014, 05:58 PM   #91
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Default Re: Polite disagreement with Sir Pudding

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Originally Posted by fredtheobviouspseudonym View Post
So it was possible, although any FDC control would work better.
How often do you have the situation of a forward observer and no FDC? A lot of infantry mortar use appears to be along the lines of "the enemy is somewhere thataway", and you don't really need a FDC to randomly shell a city.
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Old 07-28-2014, 07:43 PM   #92
sir_pudding
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Default Re: Polite disagreement with Sir Pudding

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Originally Posted by fredtheobviouspseudonym View Post
However, in WWII 60 & 81 mm mortars (US) were infantry weapons.
They still are.
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I'm pretty familiar with the US WWII infantry battalion TO&E and there were no people assigned to an FDC.
This shows USMC 81mm Mortar platoons with either 56 or 74 Marines, 4 guns and 6 man gun teams. That leaves 24 and 50 enlisted Marines unaccounted for respectively.

I've seen the WII era plotting boards (M1) in museum displays. They are nearly the same as the current M16 Plotting Board.

Besides, what you are saying just isn't possible. Geometry hasn't changed since the 1940s.

The site I linked to above shows aiming stakes and the M4 sight (which is also not significantly different from the M64). Mortars were used in WII for indirect fire.

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In a static position with dug-in weapons, of course, the infantry mortars might well be subordinated (& wisely so) to a superior organization's FDC. However, in moving, the infantry mortars were pretty much on their own.
I really don't think that works. Maybe you aren't understanding that the FO can't give gun dope directly to the gunner? The FO is out there someplace with binoculars, a map, a compass and a radio. The gunner and a-gunner can't possibly operate the radio and the gun at the same time. Somebody in that platoon was using a radio, and somebody (probably at least two somebodies) were operating M1 plotting boards.

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In E.B. Sledge's book, "With the Old Breed," the author was in a USMC 60 mm mortar unit. He has at least one narrative of indirect mortar fire controlled by the squad and without the intervention of an FDC.
I read that book years ago, so I don't exactly remember the details.

EDIT: I've just reviewed the sections in the book when he discusses fire missions. He actually gives very little details about fire commands, and the word "deflection" doesn't appear to be in the book at all. Mostly he talks about the effect of the weapons on the enemy, and on the physical experience of firing a mortar.

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Old 07-31-2014, 02:25 AM   #93
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Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Just for kicks, are there existing rules for using machine guns in indirect fire? Is that gunner(it doesn't seem likely, since they seem to use aiming stakes/posts) or Artillery? And it would require FDC, too, wouldn't it?
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Old 07-31-2014, 08:38 AM   #94
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Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Serious question for sir_pudding, then:

How would you handle an extremely light (52mm) mortar – no bipod, just a strap, and no sight better than a spirit bubble – in the hands of a six-man "split A" where just two are qualified on the weapon, and one of these is observing over a ridge two meters ahead of the other, who is below the ridgeline to avoid having his head shot off? The gunner has no LoS; his mate does. The other four men are providing security or otherwise occupied, and there's no platoon or even full squad, just what amounts to a glorified fireteam – operating independently – firing a fancy grenade launcher in a high arc to clear a hill. To me, that doesn't sound like what GURPS calls Gunner, but if you disagree, then fair enough.

The answer is of interest because in most RPGs, there is no platoon and there aren't 20-70 other people around for backup. There are four to six PCs winning the war by themselves, like in an action movie. But just as many action movies go for small-scale realism against a backdrop of large-scale ridiculousness, many action campaigns go for roll-by-roll and item-by-item detail against a backdrop of hand-waving. I think this case is far more interesting than the purely realistic one to the typical gamer, which is why I'm curious to hear the opinion of someone trained on a mortar.
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Old 07-31-2014, 10:47 AM   #95
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Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

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Serious question for sir_pudding, then:

How would you handle an extremely light (52mm) mortar – no bipod, just a strap, and no sight better than a spirit bubble – in the hands of a six-man "split A" where just two are qualified on the weapon, and one of these is observing over a ridge two meters ahead of the other, who is below the ridgeline to avoid having his head shot off? The gunner has no LoS; his mate does. The other four men are providing security or otherwise occupied, and there's no platoon or even full squad, just what amounts to a glorified fireteam – operating independently – firing a fancy grenade launcher in a high arc to clear a hill. To me, that doesn't sound like what GURPS calls Gunner, but if you disagree, then fair enough.
I'm inclined at this point to call all fires from high-angle fire cannon Artillery. This makes the Low-Tech weapons consistent with everything else. At any rate in this situation, they are no better than pre-TL5 guns with no bipod, sight and aiming stakes. So they are shooting Blind for the -10 and an equipment penalty too, I suppose they are using something to reference where the tube is pointed, so -5 for improvised equipment. Presumably they get the +4 for targeting an area with a lobbed shell, though. I'm not exactly clear on that.

The "observer" probably doesn't even need to provide a grid or polar call for fire, as there's no way to actually use them in this situation anyway, but rather is probably just pointing or giving a compass bearing and a range estimate. His corrections don't need to be very precise either, as there's no way to use them with any precision.

I reviewed the rules on GURPS High-Tech p. 138 and I can't find the part that Icelander was talking about. By RAW, there doesn't appear to any penalty for not having any fire control at all. Obviously, the observer isn't getting any bonus for fire control, and is rolling at the normal penalties (assuming he at least has basic equipment: binoculars and compass).

The thing the observer probably ought to do is just call for immediate suppression and not bother with corrections, anyway. Destroying a mobile enemy unit with corrected fire from a single gun is probably futile anyway. Just get as many rounds down on them as quick as possible!

On the other hand the Scatter rules (B414) are very generous and it's actually nearly impossible to miss with mortars (within 25m is considered a hit) in GURPS (without a critical failure). Your 52mm shells are going to be on target if they fail by no more than 25, be within the blast radius if the roll fails by no more than 16 and can possibly hit with shrapnel if the roll fails by 10 or less! As subsequent shot will scatter randomly, spreading the effect over the target area, the observer is probably best off just calling for an immediate suppression in the first place.

If I were to write an expansion for the rules in this area, I'd want to make some rules for fire control, and I'd want to make a change to the Scatter rules that applies to very long range fire that allows for scatter of hundreds of yards.

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Old 07-31-2014, 06:04 PM   #96
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Default FDC in infantry mortar units --

I'll have to go back and re-read my US Army Field Manual (WW II era) on mortar gunnery but IIRC most of the extra guys in the Army heavy-weapons company were carrying ammo for the 81s.

Remember that in theory the infantry company was supposed to carry everything on their backs but the field kitchen. So, since 81 mm mortar rounds are heavy (IIRC about 8 pounds + for the normal rounds, including projectile, propellant, and case) and some 12 pounds for the heavy projectile) you'll need about 50 guys to carry c. 200 rounds for the four tubes.

It's quite possible that a heavy weapons company had a few guys who could & did use a plotting board. I've tended to think of an FDC as a large operation with multiple charts, boards, and a fair number of guys to handle all the math.

Also it's not at all impossible for some FOs to be able to approximate angled corrections. Let's say the FO knows his line of sight to the target is about 30 degrees right, as measured from the target, from the line of fire. Mortarman fires and drops a shell about 300 yards short and about 60 degrees (from the target) to the right of the FO's line of sight. FO does some fast calculation (possibly with the assistance of a map and a triangle and figures "OK, that's almost exactly 90 degrees to the right of the line of fire. So he says "Maintain the range (or whatever the military term for it is) and shift 300 yards left."

Now of course he's likely to be off -- the next round won't land on target -- but by a series of these he will eventually get rounds on target. An FDC will always get rounds on target quicker -- but it's not impossible to eventually get mortar rounds on target without one, even in indirect fire.
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Old 07-31-2014, 06:18 PM   #97
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Default Re: FDC in infantry mortar units --

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Originally Posted by fredtheobviouspseudonym View Post
I'll have to go back and re-read my US Army Field Manual (WW II era) on mortar gunnery but IIRC most of the extra guys in the Army heavy
In the Marine TO&E I linked to the ammo-men were not only accounted for, but they were exactly the same as they are now.
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Remember that in theory the infantry company was supposed to carry everything on their backs but the field kitchen. So, since 81 mm mortar rounds are heavy (IIRC about 8 pounds + for the normal rounds, including projectile, propellant, and case) and some 12 pounds for the heavy projectile) you'll need about 50 guys to carry c. 200 rounds for the four tubes.
Nothing has changed. Medium mortar TO&Es from WWII include jeeps and trailers for the guns. Just like they now get HMMVs. However that never stopped them from making us hump with the guns (and SL-3 gear, and shells, and the FDC gear...) even here in the future.
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It's quite possible that a heavy weapons company had a few guys who could & did use a plotting board. I've tended to think of an FDC as a large operation with multiple charts, boards, and a fair number of guys to handle all the math.
I've done fire missions with nothing but myself (USMC Cpl., FDC Chief, 1 ea.), an M16 Plotting Board, a AN/PRC-119 SINCGARS radio, a couple of dry erase pens, a pen, my binder of Record Sheets, and half an MRE. It's not recommended (really you want at least two plotters to double check, and I did it this way (two man) many many times; the other Marine on a Plotting Board and radio, and me on a Plotting Board, filling out those all important Record Sheets, and commanding the gunline at the same time).

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Also it's not at all impossible for some FOs to be able to approximate angled corrections. Let's say the FO knows his line of sight to the target is about 30 degrees right, as measured from the target, from the line of fire. Mortarman fires and drops a shell about 300 yards short and about 60 degrees (from the target) to the right of the FO's line of sight. FO does some fast calculation (possibly with the assistance of a map and a triangle and figures "OK, that's almost exactly 90 degrees to the right of the line of fire. So he says "Maintain the range (or whatever the military term for it is) and shift 300 yards left."
Right or Left corrections don't mean anything to the gunline! They put deflection (in mils) on the sight (and this is as true for the M4 as it is for the M64) and then get back up on the stakes. Even if you are right and there was no dedicated fire direction in a WWII gun section, then somebody was still doing fire direction. Otherwise the A-gunner wouldn't know what to put on the sight, because there's not way to put "Right 300" on the sight. It's just nonsensical. Like telling you to tie your shoes in the key of G and 3/4 time.
Quote:
Now of course he's likely to be off -- the next round won't land on target -- but by a series of these he will eventually get rounds on target. An FDC will always get rounds on target quicker -- but it's not impossible to eventually get mortar rounds on target without one, even in indirect fire.
It is impossible to use the mortar sight (which they did) without deflection "dope", and it is impossible to get deflection without doing what the FDC does.

EDIT: I know, Greatest Generation and everything, but which is more likely: that every infantry company just happened to get a couple of (enlisted; probably graduated high school) guys that are way better at math then people who are really good at math today, good enough to keep a polar plot in their heads while manhandling the mortar tube or b) they had somebody with an M1 plotting board and firing tables?

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Old 05-28-2016, 01:34 PM   #98
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Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

The question of the Gunner (Artillery) and Forward Observer skills and their application to observers, FDCs and guns in real life just clarified for me in the Skill of the week: Observation thread. I'm posting my thoughts on it here, so they'll be found more readily by those interested.

Forward Observer skill as written in GURPS is not the skill used by the observer (whether the observer is an OP [Observation Post) Officer (artillery), FOO (Forward Observation Officer (non-artillery), or the gunner observing and correcting his own fall of shot with a light 60mm mortar)), the observer actually uses the Observation skill. All he is doing is saying the target is here. It involves a little more information than that in reality. For example, the target covers this area or is in a line in this direction with this spacing, I'm looking at it from here, the target is (bicycle troops in woods), I need an airburst, the enemy is dug in, etc. Observation skill is particularly appropriate because the observer becomes a target if he's spotted and he doesn't really want to be spotted. One of my OP Officers once told me that our life expectancy in battle was about fifteen seconds if we were spotted.

Forward Observer is then the skill of the FDC/CP (Fire Direction Centre/Command Post) to convert the information the observer sends into something actually usable at the gun and is only needed by those pieces that require it (or when they require it, as some pieces can lay directly in some roles but need data to lay in other roles, eq. in Canada, the guns can lay themselves for defence against tanks without requiring FDC information but would need FDC data to lay on those same tanks in indirect fire).

Artillery skill is then used by the gunners to lay the actual gun.
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Old 05-28-2016, 07:31 PM   #99
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Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

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Originally Posted by Curmudgeon View Post
The question of the Gunner (Artillery) and Forward Observer skills and their application to observers, FDCs and guns in real life just clarified for me in the Skill of the week: Observation thread. I'm posting my thoughts on it here, so they'll be found more readily by those interested.

Forward Observer skill as written in GURPS is not the skill used by the observer (whether the observer is an OP [Observation Post) Officer (artillery), FOO (Forward Observation Officer (non-artillery), or the gunner observing and correcting his own fall of shot with a light 60mm mortar)), the observer actually uses the Observation skill. All he is doing is saying the target is here. It involves a little more information than that in reality. For example, the target covers this area or is in a line in this direction with this spacing, I'm looking at it from here, the target is (bicycle troops in woods), I need an airburst, the enemy is dug in, etc. Observation skill is particularly appropriate because the observer becomes a target if he's spotted and he doesn't really want to be spotted. One of my OP Officers once told me that our life expectancy in battle was about fifteen seconds if we were spotted.

Forward Observer is then the skill of the FDC/CP (Fire Direction Centre/Command Post) to convert the information the observer sends into something actually usable at the gun and is only needed by those pieces that require it (or when they require it, as some pieces can lay directly in some roles but need data to lay in other roles, eq. in Canada, the guns can lay themselves for defence against tanks without requiring FDC information but would need FDC data to lay on those same tanks in indirect fire).

Artillery skill is then used by the gunners to lay the actual gun.
I don't think there's the slightest hint of a chance that this is the rules as intended.

I also really don't think your claiming Observation as the skill for a forward observer is actually any good. Observation is for gathering a detailed determination of what's there, ideally (though this part's a bit of a mess) without giving away that you're doing it. Being the observer for artillery is foremost about figuring out where the target (and if you're calling corrections, the fall of shot) is. They're both about looking at things, but that's really most of the commonality.
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Old 05-31-2016, 11:29 AM   #100
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Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

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I don't think there's the slightest hint of a chance that this is the rules as intended.
No, it isn't. But the RAW also doesn't match the way artillery spotting and correction is actually done: Sir Pudding did that as his primary job in the USMC, so can speak with some authority. There's also a line in G:WWII which contradicts this RAW:
Quote:
Originally Posted by G:WWII p44
Any front-line U.S. soldier with a good map and radio could be walked through calling in an artillery strike, if the need was urgent.
This doesn't seem to have been a difference between US practice and all other nations: checking a Canadian WWII artillery officer's memoirs matches the other evidence from history, and he was using British methods and equipment. I'm going to do some more research.
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