[Basic] Skill of the week: Artillery (and Forward Observer)

[Ulzgoroth]

Originally Posted by johndallman

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.

Of course the RAW model for artillery is no good. I really think we knew that.

That doesn't make Curmudgeon's statements about "Forward Observer skill as written in GURPS" remotely supportable. Forward Observer's writeup is entirely about calling and/or marking targets. There should be a skill for fire direction, but FO isn't it.

Originally Posted by johndallman

There's also a line in G:WWII which contradicts this RAW:

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.

Not sure which RAW you're saying this contradicts. But I wouldn't expect every front-line soldier to be any better at Observation than at Forward Observer.

[Curmudgeon]

Originally Posted by Ulzgoroth

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.

As background, let me point out that I was employed as an artilleryman in the Canadian Forces for thirty years, eight in the militia and twenty-two in the regular forces. I spent five years on the guns, including one year as a detachment commander, twenty years as a CP technician, one year as an OP tech and four years in cross-training as Driver (wheeled), driver (tracked), communicator and combat storesman. I am not talking through my hat, I've actually done it and I am saying that GURPS Observation skill is a better fit for what a real life observer for the artillery does than Forward Observer is. Now, I'll allow that a familiarity to apply Observation to the artillery is reasonable but as I said earlier eight to sixteen hours familiarization is sufficient.

Originally Posted by Ulzgoroth

That doesn't make Curmudgeon's statements about "Forward Observer skill as written in GURPS" remotely supportable. Forward Observer's writeup is entirely about calling and/or marking targets. There should be a skill for fire direction, but FO isn't it.

The only thing I said about "Forward Observer as written in GURPS" is that it doesn't match up with what the observer does as Observation does and I explained with examples why that's so.

I will grant that Forward Observer as written doesn't match up with what the FDC/CP does but, particularly given the reluctance expressed by Kromm to create a separate skill for the FDC, I think rewriting the Forward Observer skill to be the skill of the FDC/CP makes a lot of sense, and is what I was advocating (unclearly), since it:
a) doesn't result in skill bloat;
b) solves the problem of some artillery needing the FDC/CP data in an essential way, while others work perfectly well with "shift your fire to there" by eyeballing it;
and c) gets rid of an unneeded extra skill for non-artillery personnel who need support from the official* artillery.

*There really isn't a good term for the guns/howitzers as direct/general support as opposed to the mortars integral to the infantry or the support of naval guns to marines (or other troops in amphibious operations), which are artillery but not Artillery artillery.

Originally Posted by Ulzgoroth

But I wouldn't expect every front-line soldier to be any better at Observation than at Forward Observer.

Neither would I, but most front-line soldiers are likely to have Observation because it's a generally useful skill on the front line, while most front-line soldiers don't have Forward Observer skill!

[Ulzgoroth]

Originally Posted by Curmudgeon

As background, let me point out that I was employed as an artilleryman in the Canadian Forces for thirty years, eight in the militia and twenty-two in the regular forces. I spent five years on the guns, including one year as a detachment commander, twenty years as a CP technician, one year as an OP tech and four years in cross-training as Driver (wheeled), driver (tracked), communicator and combat storesman. I am not talking through my hat, I've actually done it and I am saying that GURPS Observation skill is a better fit for what a real life observer for the artillery does than Forward Observer is. Now, I'll allow that a familiarity to apply Observation to the artillery is reasonable but as I said earlier eight to sixteen hours familiarization is sufficient.

Forward Observer is by definition "the skill of being a “spotter” for artillery". That is the very first sentence of the skill's description. Unless you are saying that real life observers do not spot for artillery, it makes no sense to assert that that skill is not what they do.

(They might, of course, do more than one thing. Most adventure-like jobs involve more than one skill.)

Originally Posted by Curmudgeon

The only thing I said about "Forward Observer as written in GURPS" is that it doesn't match up with what the observer does as Observation does and I explained with examples why that's so.

I will grant that Forward Observer as written doesn't match up with what the FDC/CP does but, particularly given the reluctance expressed by Kromm to create a separate skill for the FDC, I think rewriting the Forward Observer skill to be the skill of the FDC/CP makes a lot of sense, and is what I was advocating (unclearly), since it:
a) doesn't result in skill bloat;
b) solves the problem of some artillery needing the FDC/CP data in an essential way, while others work perfectly well with "shift your fire to there" by eyeballing it;
and c) gets rid of an unneeded extra skill for non-artillery personnel who need support from the official* artillery.

*There really isn't a good term for the guns/howitzers as direct/general support as opposed to the mortars integral to the infantry or the support of naval guns to marines (or other troops in amphibious operations), which are artillery but not Artillery artillery.

I don't really think that throwing out the entire definition of Forward Observer as written and stuffing the missing fire-direction skill under it's inappropriate name is improving the structure of the skill list...

I'm not sure how this is supposed to help with (b), or what specific contexts you have in mind. The example of direct fire against tanks you mentioned in a previous post is, by the rules, actually done with Gunner (Cannon) and the standard ranged combat rules.

And for (c), it gets rid of a skill that has military specialties defined around it.

Originally Posted by Curmudgeon

Neither would I, but most front-line soldiers are likely to have Observation because it's a generally useful skill on the front line, while most front-line soldiers don't have Forward Observer skill!

You agree, except you think the exact opposite?

[johndallman]

How about we step back and look at the tasks a bit?

The spotter needs to know where he is, where the target is, and to tell the FDC where rounds are falling relative to the target.

The FDC takes that information, the position of the guns, the wind, and all the other artillery factors into account and calculates the settings for the guns.

The gunners make those settings on the guns, feed them shells and fire them.

What have I missed?

[Eukie]

Can't Forward Observer be used for Forward Air Control purposes too?

High Tech mentions Predicted Indirect Fire, which is done by a gunner who fires onto a location identified on a map. This is basically how all indirect fire from an artillery piece works; all the artillery spotter can do is tell the FDC/Battery Command Post where on the map to fire, and call for corrections to fire.

Anyone who can report a location on a map, a bearing, and a range, can do the first part of this. The FDC/BCP asks them where they are, the bearing to the target, and the range to the target. This tells the FDC/BCP where on the map they should fire. The second part can also be done by basically anyone capable of elementary mapping/survey tasks; they report report whether the round hit on the far or near side to the target relative to themselves, and whether it hit too much to the left or right relative to the line between themselves and the target.

The skill of an artillery observer, beyond that is, to make a long story short, basically a combination of knowing how the artillery pieces can be used, how they should be used, and the military procedures for using them. This is more Strategy (Artillery), Expert Skill (Military Science), and a narrow specialization of Soldier.

An artillery Forward Observer is a trained task, but I don't think it's the kind of trained task that it makes sense to describe as a GURPS-Skill; it's more Navigation + Strategy + Soldier. Much like, say, Sniper is a task in the military, but GURPS doesn't have a Sniper skill, since it's more adequately Guns (Rifle) + Camouflage + Stealth.

In short:

Artillery spotter: Navigation. (Optional: Soldier, Strategy, Surveying)

FDC/BCP: Navigation, Artillery. (Optional: Soldier, Cartography)

Artillery gunner: Gunner (Cannon) and/or Artillery. (Optional: all skills of an FDC/BCP)

Where Artillery is the navigation-based skill of calculating where to fire based on one or more map references. Artillery can then also include the operation of the guns (much like how Guns is both the skill of firing a gun and reloading it), or that can fall to Gunner (Cannon), since Gunner (Cannon) is the skill of adjusting and reloading a cannon (and also firing it as LOS targets).

[Curmudgeon]

Sorry for the delay in replying but my response turned out to be longer than anticipated, this will be a multi-post response.

Originally Posted by johndallman

How about we step back and look at the tasks a bit?

The spotter needs to know where he is, where the target is, and to tell the FDC where rounds are falling relative to the target.

The FDC takes that information, the position of the guns, the wind, and all the other artillery factors into account and calculates the settings for the guns.

The gunners make those settings on the guns, feed them shells and fire them.

What have I missed?

Originally Posted by Eukie

Can't Forward Observer be used for Forward Air Control purposes too?

High Tech mentions Predicted Indirect Fire, which is done by a gunner who fires onto a location identified on a map. This is basically how all indirect fire from an artillery piece works; all the artillery spotter can do is tell the FDC/Battery Command Post where on the map to fire, and call for corrections to fire.

Anyone who can report a location on a map, a bearing, and a range, can do the first part of this. The FDC/BCP asks them where they are, the bearing to the target, and the range to the target. This tells the FDC/BCP where on the map they should fire. The second part can also be done by basically anyone capable of elementary mapping/survey tasks; they report report whether the round hit on the far or near side to the target relative to themselves, and whether it hit too much to the left or right relative to the line between themselves and the target.

The skill of an artillery observer, beyond that is, to make a long story short, basically a combination of knowing how the artillery pieces can be used, how they should be used, and the military procedures for using them. This is more Strategy (Artillery), Expert Skill (Military Science), and a narrow specialization of Soldier.

An artillery Forward Observer is a trained task, but I don't think it's the kind of trained task that it makes sense to describe as a GURPS-Skill; it's more Navigation + Strategy + Soldier. Much like, say, Sniper is a task in the military, but GURPS doesn't have a Sniper skill, since it's more adequately Guns (Rifle) + Camouflage + Stealth.
URPS
In short:

Artillery spotter: Navigation. (Optional: Soldier, Strategy, Surveying)

FDC/BCP: Navigation, Artillery. (Optional: Soldier, Cartography)

Artillery gunner: Gunner (Cannon) and/or Artillery. (Optional: all skills of an FDC/BCP)

Where Artillery is the navigation-based skill of calculating where to fire based on one or more map references. Artillery can then also include the operation of the guns (much like how Guns is both the skill of firing a gun and reloading it), or that can fall to Gunner (Cannon), since Gunner (Cannon) is the skill of adjusting and reloading a cannon (and also firing it as LOS targets).

First, thanks for the link, Eukie. I don’t have 4th edition High Tech but it helps to know what they think happens with Artillery fire. While the mechanics roughly simulate the effects/results they want to model, the reality is very different. In part this is because the information provided in the link is indicative of a problem in GURPS understanding of the situation. Generally speaking, the information in the link is a mixture of bang-on facts, sort-of-true if you look at it in a slightly skewed way, and outright just-plain-NO-it’s-not-even-close-to-being-true, so some sorting is needed.

I think johndallman’s suggestion of stepping back and looking at the tasks is a good one but I’m going to start by describing what happens in a very stripped down, generic way and distinguish between what could be done in theory and what happens in reality and why and how the two differ. I’m also going to be noting some historical variations and what happens when you leave our very simple stripped down case. Then I’ll try to construct a closer-to-reality procedure.

The very simplest case would be a single gun observing and correcting its own fall of shot. The gun is obviously crewed using Gunner (Cannon) skill and by definition, since the gun can see its target it isn’t using indirect fire and thus Forward Observer skill isn’t needed and Observation (possibly with a familiarity for Artillery or Cannons) is the other skill being used.

The next simplest case is one using smallest sub-unit available, either a four-gun troop or a six-gun battery depending on the time-period. [I was around during the most recent transition from troop-to-battery back in the 1970s, so I’ve seen both.] In this case you have the guns with their detachments [crews for Americans], the TSM [troop sergeant major], one or more CPs (command posts [FDCs for Americans]), one or more OPs (observation posts), and some integral support functions (quartermaster, transport, signals, medical, but aside from the cooks and medical assistant, these are all cross-trained artilleryman rather than other tradesmen). Local defense (eg., machine guns, rocket launchers, etc.) are crewed by the troops as a secondary function rather than having dedicated support from the infantry.

This is the point where indirect fire starts to be commonly employed. The observer may be attached to an infantry or armoured unit to provide artillery support or he may be deployed independently to provide general support for a whole formation (brigade, brigade group or division, depending on the particular organization).

A brief aside on command organization because it has an effect on how things are done in different armies. There are two ways to organize command of the artillery. One way is to put the commander in the observer slot. This is the method used by the UK, Canada and some other Commonwealth countries. The other way is to put the commander in the FDC slot, which is used by the U.S. and countries that were influenced by the U.S. Everyone will use one or the other but those are the only ones I’m specifically calling out. The major difference resulting from this is roughly as follows: observers as commanders make a Call for Fire and, barring intervention from higher up, he assigns the target and a weight of fire with the assurance that he’s going to get exactly what he asked for; in FDC as commander systems, the observer makes a Request for Fire, indicating the target and desired weight of fire. While he’ll usually get it, the FDC as commander may change the weight of fire or deny the use of the guns entirely at his discretion (usually based on needs indicated by a higher authority).

The observer doesn’t need to know the guns’ location at all in order to engage in indirect fire. All he needs to know are the answers to two questions: “Is the target within the guns range?” and “Are the guns going to be delayed because they need to shift about before firing?” He knows the answers to both questions because he either told the CP to pick a position that would let them reach a given minimum range and point the guns in this general direction, or the FDC told him that was what they had done.

He sort-of needs to know his location but the only location that he absolutely needs for indirect fire is the target’s. The target’s location is usually a map spot but it can be given as polar co-ordinates from a known point (not just the observer’s position but a registration point, witness point, recorded target or a map spot). The sort-of needing to know his location comes from how we get a map spot. We look at the feature on the ground and say that’s at two o’clock to me and about eight hundred metres from me, give or take. I think I’m here on the map, so two o’clock and about eight hundred metres would put it about here, and yes, that’s a tree in a loose group of trees on the map, too, so that’s it and the mapspot is GR (grid reference) 123456.

In theory, the CP doesn’t have to be located with the guns, it could be located as many miles from the guns as the observer is. It could even be located with the observer. It isn’t for a couple of reasons. While the guns and CP could be linked by radio and/or field telephone (and often are), these means of communication can be jammed or the lines cut. This is true of the observer as well, but you can’t do much about that. He has to be well forward and use long distance communications. For the CP, it’s handy to be able to just crack the door open and yell the information to the guns or send a runner. On the face of it, it wouldn’t seem to make a lot of difference if you put the CP with, or at least handy to, the observer. If the comms link goes down the CP and guns are effectively useless, so what difference does where they’re useless make? Putting the CP close to the Op means having a bigger, more observable footprint which in turn is more likely to reveal the observer’s position. Second, I did say earlier that even a troop may have more than one OP operational at once and cutting the comm link to one doesn’t necessarily cut the comms links to them all, so you don’t really want the CP up with the OP.

Post 1 of 5.

[Curmudgeon]

To turn the target’s location into something the guns can use, you would plot the location of the guns (here) and the location of the target (there) and then measure the bearing (being careful to go from the gun to the target and not the target to the gun) and find the distance (range). [Incidentally, this is why most target locations are sent as map spots rather than polar coordinates. With polar coordinates, you have to plot the known location, find and plot the target from that location and then find the bearing and range, so you’ve got an extra step with polar coordinates.] At its crudest, you could take a protractor (like the base of a Silva compass), put it over the guns’ location, run a string from the protractor to the target plot, read the angle, mark the string’s position over the target with your thumb and swing the string up and line it up against the map grid to get an estimation of the range. Even with something that crude, you ought to be able to get within 20₥ for bearing and 500m for range which is good enough for an initial round that’s going to be adjusted. You can get closer than that by using better equipment than a compass and string.

In theory, if you have something like an old twenty-five pounder, with its range cone, a bearing and range are good enough to fire off. You set your range and the charge on the cone and when you level the cone, the gun is laid at the proper elevation to reach that range without having to calculate an elevation.

From this, you might think that you could put a range cone on every gun, get rid of the CP entirely and just have the gun’s detachment commander figure out the bearing and range from his map and compass and save the expense of a CP. The reality is that it doesn’t actually save enough to be worthwhile since then every gun has to have a radio [and a range cone] (while that’s usually the case, not every nation does so, just as not every nation puts a radio in each and every tank) and it’s easier to have someone who doesn’t have to look after a multitude of other things make the calculation once for everybody in the troop.

As for the guns proper, while gun drill covers the basics of laying the gun, (eg. bearing goes here, elevation goes there), it involves other things as well. In most nations’ artillery, it’s probably a fair statement that there’s at least as much of the gun drill devoted to error trapping as there is to actually laying the gun. For example: checking that the bearing the detachment commander heard is the same as the bearing the CP gave him, then checking that the bearing the layer heard from the detachment commander is the same as the bearing the detachment commander gave him and then checking that the bearing put on the sight is the same as the bearing he was given and then seeing that the gun is actually correctly laid on the aiming point at that bearing and going through pretty much that same procedure for ever part of laying the gun, the elevation, the type of projectile, the type of fuze, the fuze setting and so on, right down to the moment the order to fire is given.

Once the fired round arrives at the target, the observer sends a correction. This is a very simple idea, though it does require a little bit of calculation at the time. First, illuminating rounds aside, all adjustment is done with ground bursts, even if the final fire will be an airburst, so that the observer can see where the round is actually hitting. To make the correction, the observer has to tell the CP the bearing he’s looking at when he makes the correction, since the line to the target that he’s making the correction from and the line to the target that the gun needs to make the correction from are rarely the same. This lets the CP rotate the correction to the guns line.

As an example, if the observer is looking at 2200₥ and the guns are firing at 1600₥, the OP’s correction of R[ight]120, D[rop]800 becomes L[eft]600, A[dd]300 when applied to the guns and a new bearing and range have to be determined from the corrected plot. That is a point that may not necessarily be appreciated. The correction creates a new plot for the target’s location, it’s not a correction that can be applied directly to the guns’ firing data.

The actual corrections are very simple things. The first correction is always a correction to line (i.e., to the right or left of the target relative to the observer. If it’s also plainly long or short of the target of the target, it may include a range correction as well. After that first correction (which we’ll assume was for line only), range corrections are extremely simple. The observer picks a correction based on how close he thinks the round landed to the target (always a multiple of 2^n and whether the round was long (behind the target relative to him) or short (in front of the target relative to him) and then proceeds to bracket the target.

As an example of the pattern corrections take:
OP (first round): R[ight]120, D[rop]800. [round to the left and back of the target]
OP (second round): D400 [round still behind target]
OP (third round): A[dd]200 [round now in front of target]
OP (fourth round): A100 [round still in front of target]
OP (fifth round): MTSQ. [The observer could continue splitting the bracket down to 50, 25, and more rarely 12m, but in this case, the target is within the lethal radius of the shell and that’s going to be good enough that he’s switching to a time fuze and adjusting the airburst.]
OP (sixth round): D[ow]n20 [the round is bursting too high for optimum damage]
OP (seventh round) U[p]10, at my command, 4 rounds, 15 seconds, fire for effect! [The adjustment is complete and since he’s not going to split the bracket further for the airburst, the OP can go straight into firing the guns. In this instance, he’s holding the guns to fire together and he wants four rounds from each gun spaced 15 seconds apart [for each gun, if he wants the guns to fire an interval sequentially, there’s a different order for that]
CP: Ready! [all guns are now laid on the target and loaded]
OP: Fire! [the detachment commanders now order their guns to fire and the projectiles are on their way to the target.]

In theory, given a map spot of the target, no correction should be necessary as the bearing and range are a perfect mathematical construct derived from the information provided and the guns laying instruments are accurate enough to put the round within no more than a few tens of metres of the target, which for most projectiles is more than accurate enough to do some significant damage to the target.

Obviously, something happened somewhere to cause errors of the size we’re talking about in the example (and the values of the corrections in the example are fairly typical in reality), so what happened? Well, in our very simple example we haven’t made any allowance for variation from standard conditions. For example, our range and bearing made no allowance for weather condition, worn barrels, odd projectile weights, hotter or colder initial temperatures of the propellant and so on, but even if we were to factor those conditions out, we’d still end up with patterns very much like this (perhaps starting with a 100 or 200 metre range correction).

The primary source of error necessitating corrections is the difference between where people think things are and where they really are. When the OP sets up, the observer makes a map spot of where he thinks he is on the map and given a good eye for the terrain and a really good MK I eyeball, he may really be somewhere within 50m north or south and 50m east or west of that map spot. Likewise, when the CP sets up the guns, the officer makes a map spot of where he thinks he’s placed the guns and again, he may actually be somewhere close to that. So on average, given good map reading, the OP is probably somewhere within 75m of where he thinks he is and the guns are somewhere within 75m of where the CP thinks they are, but the two errors aren’t likely to cancel each other out and that’s the source that creates the need for corrections in the first place. GPS helps but because they give some deliberately false readings (so they’re less helpful to the enemy and the errors are even bigger if you don’t have the codes to get the military grade locations as opposed to the civilian ones) they treated as about as good as a very good (accurate to within 10m easting and 10m northing) map spot.

One final point for our simple case and it’s important, the CP officer sites and sights the guns. Siting the guns has two considerations: not allowing more than two guns to form a straight line that enemy aircraft can exploit in making a bombing run, and spacing the guns far enough apart that an ammunition explosion on one gun won’t have any other gun within its lethal radius. Sighting the guns is the difference between all the guns are pointing at 2100₥, more or less, and all the guns are pointing at 2100₥ exactly. The technical term for it is putting the guns in parallel line and it’s important because it’s what allows the corrections for one gun to apply to them all. If the guns aren’t in parallel line, each gun needs correcting individually. The guns will gradually shift out of parallel line as they’re fired, so they’re checked periodically and brought back into parallel line before the error becomes noticeable.

Post 2 of 5

[johndallman]

Originally Posted by Curmudgeon

... get within 20₥ for bearing and 500m for range which is good enough for an initial round that’s going to be adjusted.

This notation - ₥ - is unfamiliar. I'm guessing it means "mils", probably NATO mils (6400 to a complete circle), but an explanation would help.

[Curmudgeon]

Now for some points about the High Tech link.

Yes, indirect is always “blind” from the gunner’s point of view. However, it’s not true that he doesn’t benefit from his gun’s Acc modifier. If anything laying the gun on target is easier in indirect fire because you’re laying on a static aiming point, not something like a tank that’s taking active measures to break your lay on him. The -10 modifier to skill is okay but the fluff really should indicate that the source of the -10 to skill comes from the observer’s inaccuracy in determining the target’s position.

Yes, predicted indirect fire is based on an uncorrected map spot but it’s not a hard limit that it can’t be corrected. The usual employment of predicted indirect fire comes up in two common cases. First, when doing a fire plan in support of an attack, the observer will often have fifteen or more targets that he wants to engage but the plan is needed ASAP, so he’ll choose which targets are considered critical and fire them as indirect observed fire and relegate the others to indirect predicted fire and hope that’s good enough. If he has the time and attention to spare, he could correct predicted indirect fire just like any other indirect fire. The other situation occurs when the observer picks out likely features in his zone of observation, either features the enemy is likely to try to occupy, or prominent features to adjust fire onto the enemy from. In either case, there may be twenty or more targets chosen and predicted indirect fire is “good enough” as the observer doesn’t want to waste ammunition correcting a target that may end up never being used and the first round data being figured in advance is advantage enough.

As for high-angle and low-angle missions, using high-angle missions to clear intervening obstacles is spot-on. However, the three thousand yard break between high-angle and low-angle missions is nonsense. You can fire a low-angle mission or a high-angle mission out to the full range of the piece (sort-of). The sort-of comes from the manufacturer often allowing the piece to be physically elevated past the point where it’s actually safe to fire it. As an aside, by definition, guns cannot fire high-angle. If a piece isn’t a mortar and can be elevated to fire high-angle, it’s a howitzer and not a gun, regardless of what the manufacturer chooses to call it.

The recoil of an artillery piece is fierce. Even with the recoil reduction system, the barrel will slide back in its cradle or sleigh until the breech is actually off the cradle or sleigh. Even in high-angle this isn’t usually a problem but once you get past about 80° elevation, the recoil will slam the breech into the ground (as a rough guide, near top of its elevation and at full propellant charge, the breech will bury itself about 18” deep). On a towed piece, you can dig to create clearance for the breech but on a SP piece, the breech is going to slam into and through the floorboards, possibly break one of the lines (coolant, transmission, etc. and then hit the actual armour of the chassis. Regardless of whether it damages the breech, the vehicle or both the result isn’t good.

3000 yards badly underestimates the range artillery is employed at. Artillery is usually deployed well back from your own front, two to three miles towards the rear. A light howitzer, like a 105mm, typically has a range of a bit more than seven miles or about 12,300 yards, letting it reach three or four miles deep in the enemy’s front.

As a revised system for artillery, I’d suggest:

The observer makes an Observation roll at -10, and takes a further -4 penalty if he doesn’t have the (Artillery) familiarity. The Margin of Failure on Observation roll is applied as Scatter to the first round, as follows:

Scatter distance for a miss is equal to the square of the margin of failure times 10 yards. If the Scatter direction is 2, 3, 4 or 5 and the Margin of Failure is 5 or more, a line correction is required on the next round. If the Margin of Failure is 11 or more, the line correction cannot be coupled with a range correction, i.e. the first correction is for line only.

For the second and all later rounds, scatter is 1-3 long and 4-6 short with no further line corrections required.

The initial range correction is determined by the Margin of Failure as follows:

Margin of Failure	Initial Correction*	Additional corrections required
1	                Target round	        0**
2	                  50	                0***
3 or 4	                 100	                0***
5	                 200	                1***
6	                 400	                2***
7 or 8	                 800	                3***
9+	                1600	                4***

* Initial Correction was determined by multiplying the distance by the sine of 60°.
** (the actual error is less than 12 yards, so no further split is possible)
***unless a closer split than 100 yards is required, add 1 for each additional split required.

Post 3 of 5

[Curmudgeon]

An artillery piece [i]cannot[i] use indirect fire without a CP/FDC present. The CP uses Artillery skill with the following rules:

Unless the observer requests a pattern of fire other than the fall of shot dropping about the target, (eg. all rounds on the exact same spot, all rounds strung out in a line, etc.) the Margin of Failure/Margin of Success applies as penalty/bonus in seconds to the time it takes to calculate the fire with a base time of 60 seconds for an initial round and 30 seconds for a correction. (eg., a margin of success of 5 will let the guns fire in 55 seconds and a margin of failure of 10 will take 70 seconds for a first round.)

If a special pattern is requested, the Margin of Failure adds a penalty of half the margin of failure (rounded up) additional corrections. (eg. The observer had a margin of failure of 8 and requires 4 corrections to hit the target in a line. The CP had a margin of failure of 5 on their Artillery roll, so the observer must make 3 additional corrections for seven total to bring the fire on target.)

At the artillery piece, Gunner skill is used for indirect fire* and any non-critical failure adds the margin of failure as a cumulative time penalty to fire. (e.g. If the Gunner skill had a margin of failure of five it would add a further 5 second penalty and in the previous example would either bring the time back up to 60 seconds, essentially squandering the bonus from the CP or bring the time up to 75 seconds.)

A critical failure is rerolled and on anything but a verified critical failure, results in the gun being out of action for a period of 2d6 times 10 seconds and may represent anything from clearing a misfire to equipment failure to a laying error that results in the adjustment being passed to another gun.

On a verified critical failure, there is an ammunition accident. This doesn’t necessarily take place at the gun, it includes muzzle detonations (the fuze went off prematurely within 200 m of the gun [resolve damage normally]) and firing the wrong charge (usually meaning that fewer charge bags were removed than should have been). For a wrong charge, roll 1d6 times five hundred yards and the round landed that much further long, distance is capped at the maximum range of the gun.

* Artillery actually trains in indirect fire as a primary skill and direct fire as a secondary, but the differences between direct fire and indirect fire amount to two different familiarities of the Gunner skill and are broadly applicable across different pieces, i.e. someone trained for direct and indirect fire on a towed 105mm howitzer will need less than a minute to be able to lay a 155mm SP howitzer for direct and indirect fire without a skill penalty and less than 5 minutes to figure out using a range cone on a 25 pounder.

For Eukie: Re: Forward Observer and Forward Air Controller.
They are broadly similar and I’ve known FOOs (Forward Observation Officers) who were also FACs (Forward Air Controllers) but it’s not universally the case. OTOH, much like teaching a non-artillery person to act as a Forward Observer, FAC can be taught in as little as two days, and doesn’t require knowing Forward Observer, arguing that they’re both really familiarities of Observation, rather than separate skills.

Post 4 of 4

The post about less simple cases will be coming later.