07-14-2014, 01:08 PM | #21 |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
It never came up, to be honest. For one PC peeking out and observing the fires of another PC's mortar, there was no need – there were two people involved (one with Forward Observer, one with Artillery) and they interacted directly. For PCs calling in off-map fires, it was irrelevant . . . the entire apparatus from "the other end of this radio call" to "shells falling over there" was a black box.
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07-14-2014, 01:11 PM | #22 | |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
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07-14-2014, 01:13 PM | #23 | |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
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07-14-2014, 01:25 PM | #24 | |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
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07-14-2014, 04:42 PM | #25 |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
I found some years ago some WW II US military manuals on line which included some on artillery gunnery. I'm no expert but, IIRC, this is what I remember for mortars . . .
You have a marker, an "aiming stake," set up some distance from the mortar tube. This is a reference for azimuth change. In c. 1941 the US Army had its sights measured in "infantry mils". One infantry mil is 1/6400 of a full circle; there are c. 17.8 such mils to a degree. A displacement of one mil of azimuth will be about 1/1000th of the range. (Actually, for an infantry mil it's 1.01 thousandth -- but that error will be lost in the normal error of the shell's flight.) So if you're firing at 800 yards, and you're dropping rounds at the right range and 50 yards left, you use the sight and come right about 50 yards divided by point-8 mils ({800 yards divided by 1000} mils, or c. 62.5 mils). It's complex, and requires some mental gymnastics in combat, but long training usually produces adequate results. For range, most mortarmen have a pretty good idea of how much a change in elevation of a few mils will alter the point of impact at what range. For more precise work, every set of mortar shells will have a range card, showing this information at various ranges & elevations. You have to correct, of course, for differences in elevation between yourself & the target, wind, humidity, and, if at enough range, the rotation of the earth. Example -- the observer says "Left fifty yards, down sixty." Mr. Mortarman says to himself (in those days, always himself) "At eight hundred yards that's 62.5 mils. So he adjusts the dial sight on the mortar tube 62.5 mils to the right (which moves the barrel to the left). He then turns the traversing crank and re-aligns the sight on the aiming stake. Now he's fixed for azimuth. "Range -- to drop about sixty yards with this weapon & this charge at this range I need to raise [for mortars, to shorten range you increase elevation] the tube about (figure out of my [deleted]) 75 mils." Add 75 mils to the bubble sight on the tube. Crank, crank on the elevating handle until the bubble comes level again. Then either tell the observer "Round on the way!" or simply drop-shoot the round and assume Joe Observer knows the sound of a round departing the tube. I'd expect that a good mortarman would accomplish all this in a fraction of the time it takes me to tell it. [If I'm in error I invite editorial correction.] This is why for most of the last 150 odd years the artillery tries to get smart officers & NCOs to do all this under fire. |
07-14-2014, 08:55 PM | #26 | |||||||||||||||
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
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It's also very difficult (and physically demanding) to be the Gunner or A-Gunner on a mortar. It would be nearly impossible to do either job and the FDC's job at the same time and provide fires in a timely manner. There's a reason these are not just different jobs, they are considered two of the three separate elements of indirect fire (the third is the observer). Last edited by sir_pudding; 07-17-2014 at 08:26 PM. |
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07-15-2014, 08:38 AM | #27 |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
There has to be some middle ground. Extremely light mortars such as this one are meant to be deployed and fired almost on the run. Rheinmetall, the current manufacturer, had videos online a while back that illustrated it in use. A man appeared to run up, plonk the thing on the ground, pop a bunch of rounds at targets 300 to 600 meters away, and correct fire entirely on feedback from another guy. That might be manufacturer hype . . . I really don't know. But that's the only kind of mortar fire I've ever used in my campaigns, since any mortar heavy enough not to be a personal weapon in a really light squad of irregulars isn't on the menu for the sorts of adventures I run.
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07-15-2014, 09:00 AM | #28 |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
If the observer, gun, and target are approximately colinear, then the Cartesian to polar problem is pretty much as simple as fredtheobviouspseudonym suggested. Normally that can't be assumed, of course, but if the mortar is a squad (or adventuring party)-level asset it might be used that way.
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07-15-2014, 09:22 AM | #29 | |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
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X --O-- M Where X is the target, O is the observer, the dashes indicate a ridgeline, and M is the mortarman. The observer is still needed because the mortarman wants to remain in defilade to avoid having his head blown off, and can't easily operate a mortar while prone and unmoving. The prone, stationary, camouflaged observer effectively serves as an aiming periscope, but since the mortarman is relying on relayed targeting information, the skill is still Artillery, not Gunner. I have no idea how common that arrangement is, but it doesn't seem unrealistic, and it's also consistent with how a tiny team of irregulars might operate.
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07-15-2014, 10:19 AM | #30 |
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Re: [Basic] Skill of the week: Artillery (and Forward Observer)
If it helps, the old British 2" mortar was pretty much aimed by dead reckoning - you lined it up at the target, judged the distance and set the angle of the barrel by a combination of judgement and guesswork. You then fired a bomb and adjusted for fall of shot - but then you only had a range of about 500 yards and weren't likely to be using much in the way of forward observation.
Added historical trivia: First account of observed indirect fire that I can find occurs during the defence of Hougoumont in the Battle of Waterloo where a battery of the Royal Horse Artillery fired an indirect Shrapnel barrage against advancing French troops using corrections given by the commander of an adjacent battery with a direct line of sight. Also, IIRC, Naval gunnery observation was quite a big deal in WW2 (as per occurences upthread) - the USN and RN were pioneers in developing fire control shore parties and thus accquired capabilites above and beyond those of other nations. |
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artillery, basic, forward observer, skill, skill of the week |
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