Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 07-15-2014, 11:45 AM   #31
sir_pudding
Wielder of Smart Pants
 
sir_pudding's Avatar
 
Join Date: Aug 2004
Location: Ventura CA
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by Kromm View Post
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.
Quote:
Originally Posted by Ulzgoroth View Post
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.
Quote:
Originally Posted by The Colonel View Post
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.
Yes, you can fire mortars like this and many light mortars are designed to make this very easy (like the M224 with it's assault plate, firing trigger and spirit level). However this is called "direct lay" and you aim in on the target itself rather than an aiming stake. In GURPS according to the Basic Set, and confirmed by you Sean, this uses Guns (Grenade Launcher) rather than Artillery (Cannon).


Quote:
Originally Posted by Kromm View Post
I've never run an adventure where that wasn't the case for a 51mm to 60mm infantry mortar. As I said, the observer is just ahead of the mortarman; he might be prone at the summit with the mortar set up literally at his heels on the reverse slope, like this:
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.
In real life, you don't do indirect fire without an FDC even with closely colocated observers. I'm not sure how the situation you describe even works though because without aiming stakes or visibility on the target what is the gun crew aiming at?
sir_pudding is offline   Reply With Quote
Old 07-15-2014, 11:51 AM   #32
Ulzgoroth
 
Join Date: Jul 2008
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by sir_pudding View Post
Yes, you can fire mortars like this and many light mortars are designed to make this very easy (like the M224 with it's assault plate, firing trigger and spirit level). However this is called "direct lay" and you aim in on the target itself rather than an aiming stake. In GURPS according to the Basic Set, and confirmed by you Sean, this uses Guns (Grenade Launcher) rather than Artillery (Cannon).
Except for The Colonel, I don't think we're talking about the gunner having line of sight to the target.
Quote:
Originally Posted by sir_pudding View Post
In real life, you don't do indirect fire without an FDC even with closely colocated observers. I'm not sure how the situation you describe even works though because without aiming stakes or visibility on the target what is the gun crew aiming at?
What would stop them from having a stake if they need one?
__________________
I don't know any 3e, so there is no chance that I am talking about 3e rules by accident.
Ulzgoroth is offline   Reply With Quote
Old 07-15-2014, 11:59 AM   #33
sir_pudding
Wielder of Smart Pants
 
sir_pudding's Avatar
 
Join Date: Aug 2004
Location: Ventura CA
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by Ulzgoroth View Post
Except for The Colonel, I don't think we're talking about the gunner having line of sight to the target.
The demonstration of a light mortar being fired that Kromm describes sounds exactly like a direct lay. Which makes sense, light mortars are sold based on their ease of use in direct lay, nowadays.

Quote:
What would stop them from having a stake if they need one?
The situation that Kromm describes seems to be missing it. If they have time (and cover) to lay in stakes, they have time to set up fire direction.

I can tell you that the average mortarman (required ASVAB in the US is like 56 or something, IIRC) couldn't do the math that's required here. That's not Artillery skill, that's FO (FDC) or whatever we want to call the skill that the FDC uses, which if somebody has and is using on the gun, they effectively do have an FDC in this scenario. Although, I'd think that if he has to do it in his head, he ought to get -5 for improvised equipment. Of course GURPS doesn't appear to care if makes his roll anyway, so maybe it's moot.

Last edited by sir_pudding; 07-15-2014 at 12:02 PM.
sir_pudding is offline   Reply With Quote
Old 07-15-2014, 01:00 PM   #34
johndallman
 
Join Date: Oct 2010
Location: Cambridge, UK
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by sir_pudding View Post
TThe situation that Kromm describes seems to be missing it. If they have time (and cover) to lay in stakes, they have time to set up fire direction.
To make sure I'm on the right page here, the reason for the stake - or some other reference for pointing the mortar - is that it doesn't stay on target when you fire it? It jumps enough that you have to put it back on the right direction and distance after each shot?
johndallman is offline   Reply With Quote
Old 07-15-2014, 01:06 PM   #35
sir_pudding
Wielder of Smart Pants
 
sir_pudding's Avatar
 
Join Date: Aug 2004
Location: Ventura CA
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by johndallman View Post
To make sure I'm on the right page here, the reason for the stake - or some other reference for pointing the mortar - is that it doesn't stay on target when you fire it? It jumps enough that you have to put it back on the right direction and distance after each shot?
That's the reason that you have multiple stakes. You need stakes (or a visible target for a direct lay) in order to have something to aim at, at all. The sight is a very precise optical instrument, but it's completely useless if you don't have something to align it with.

The weapon does shift a lot after you fire (especially after you fire the first round which "settles" the baseplate by driving it into the ground).
sir_pudding is offline   Reply With Quote
Old 07-15-2014, 02:29 PM   #36
Kromm
GURPS Line Editor
 
Kromm's Avatar
 
Join Date: Jul 2004
Location: Montréal, Québec
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

All I'm saying is that if you're using a very light (60mm or smaller) mortar – the sort that often has a strap instead of a bipod and no sights better than a line of paint on the tube – for what amounts to direct lay but you're relying on somebody else to observe the rounds falling and speak the very same corrections he would make by hand if he were the gunner, I'd treat that as a Forward Observer-Artillery task, not as a Gunner task. The downside would be having two rolls to fail; the upside would be the possibility of keeping your head down.

As for "What are you aiming at?", I find it hard to believe that an experienced mortarman couldn't dead-reckon a guess at the first shot and correct from there, alone or with a friend. The whole point here is to emulate irregulars (not artillerymen with grids and computers and fancy sights) conducting unplanned fire as a hasty ambush or assassination attempt. The mortarman blasts something in the general area of a target he peeked at earlier, his pal tells him what the results were, and they improvise from there. It probably isn't the Proper Military Way, but it seems a lot closer to what guerrillas or assassins would do.
__________________
Sean "Dr. Kromm" Punch <kromm@sjgames.com>
GURPS Line Editor, Steve Jackson Games
My LiveJournal [Just GURPS News][Just The Company]
Kromm is offline   Reply With Quote
Old 07-15-2014, 02:42 PM   #37
Ulzgoroth
 
Join Date: Jul 2008
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by sir_pudding View Post
The situation that Kromm describes seems to be missing it. If they have time (and cover) to lay in stakes, they have time to set up fire direction.
What would it constitute to 'set up fire direction'? Particularly, what would it involve other than additional division of labor that the group doesn't necessarily have the composition to support?
Quote:
Originally Posted by sir_pudding View Post
I can tell you that the average mortarman (required ASVAB in the US is like 56 or something, IIRC) couldn't do the math that's required here. That's not Artillery skill, that's FO (FDC) or whatever we want to call the skill that the FDC uses, which if somebody has and is using on the gun, they effectively do have an FDC in this scenario. Although, I'd think that if he has to do it in his head, he ought to get -5 for improvised equipment. Of course GURPS doesn't appear to care if makes his roll anyway, so maybe it's moot.
It appears that as currently constituted GURPS does not care about the inner workings of artillery direction at all. Artillery seems to be a basket skill covering everything you need to make the shot from FDC tasks to muscling rounds, regardless of whether that's anything like how the process is actually handled.

That's not how I want it to be either, but it seems to be how it is.
__________________
I don't know any 3e, so there is no chance that I am talking about 3e rules by accident.
Ulzgoroth is offline   Reply With Quote
Old 07-15-2014, 03:06 PM   #38
Kromm
GURPS Line Editor
 
Kromm's Avatar
 
Join Date: Jul 2004
Location: Montréal, Québec
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by Ulzgoroth View Post

Artillery seems to be a basket skill covering everything you need to make the shot from FDC tasks to muscling rounds, regardless of whether that's anything like how the process is actually handled.

That's not how I want it to be either, but it seems to be how it is.
I don't see what advantage adventure stories would gain by breaking down matters further. Lots of skills are similarly broad for identical reasons: Sticking my finger into the Skills chapter at random, here's Mechanic (Vehicle Type), which covers the controls, engine, electrical wiring, windows, seating, air conditioning, and even the paint job of a vehicle. And here's Writing, which encompasses creative writing, technical writing, report writing, adcopy, editing, proofreading, indexing, and everything else to do with written words.

Given that artillery use already gets two skills (Artillery, Forward Observer), it's doing pretty good. When one person is exposed and taking care of the daring job of observing the enemy, and another gets to fire a big freakin' gun that blows things up, I can't really see it being a fun adventuring task to be the third guy who . . . consults tables. The game is about what's dramatic and fun, remember; simulation always comes second. The general guideline is "one skill per interesting task for adventurers."
__________________
Sean "Dr. Kromm" Punch <kromm@sjgames.com>
GURPS Line Editor, Steve Jackson Games
My LiveJournal [Just GURPS News][Just The Company]
Kromm is offline   Reply With Quote
Old 07-15-2014, 03:11 PM   #39
Verjigorm
 
Join Date: Jan 2005
Location: Charlotte, North Caroline, United States of America, Earth?
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Why can't we handle the FDC's skill roll as a cap for both the Mortarman and the FO?

"Grid Ad7685, 500 up, 300 right. Fire. Positive identification, drop 150, left 20. Fire. On target, fire for effect" This is my FO roll, and it determines if the aiming point will be accurate or not, correct?

Then the FDC takes this, looks at his charts/etc and converts the map co-ordinates to something the gunner can use, he rolls his skill, which caps the skill of the mortar's gunner.

The mortar's gunner then aims the weapon in the correct direction and fires. He can't be more accurate than the information the FDC supplies, right? If the FDC makes an error on his conversion, then the salvo will miss, right?

So I guess the FO roll caps the FDCs roll, which in turn caps the mortar gunner's skill roll.

Edit: Also, could I replace the FDC person with an AI at higher TLs where AIs exist?
__________________
A shadu an la illa illah Allah, we shadu anna Muhammadar Rasul
Verjigorm is offline   Reply With Quote
Old 07-15-2014, 03:20 PM   #40
johndallman
 
Join Date: Oct 2010
Location: Cambridge, UK
Default Re: [Basic] Skill of the week: Artillery (and Forward Observer)

Quote:
Originally Posted by Verjigorm View Post
Edit: Also, could I replace the FDC person with an AI at higher TLs where AIs exist?
Absolutely. No reason they shouldn't come built in to Artillery weapons at a high TL.
johndallman is offline   Reply With Quote
Reply

Tags
artillery, basic, forward observer, skill, skill of the week

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 05:41 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.