Not sure this is the best home, but let's start.
The intent of this post is to create a guide that'll make it easier for people to use artillery. Artillery can be a fun game element that works differently from any other weapon in BattleTech, but the perceived complexity of it can be offputting. Meanwhile, a different mindset is needed to make good use of it.
A second intent is to improve the document based on feedback. I consider myself a veteran player, but I'm not an expert in artillery. If some advice seems incorrect, inferior or incomplete, please comment, and the base article will be improved.
Similarly, if you've never messed with artillery before, and this post makes you think about starting, we're on the right path. Your input is extremely valuable though: it's possible for the experts to consider something to be self-evident, that isn't obvious at all to a new player. That's hard to catch.
OK, enough preamble.
Short list of bullet points, detail below.
Artillery rules: pp. 179 - 186 of Tactical Operations.
Artillery is good at:
* Area denial
* Wrecking terrain or buildings
* Wrecking battle armor and infantry
* Clearing minefields
* Causing your enemy to over- or underestimate it.
Artillery is poor at:
* Doing damage to mobile, dispersed units
* Providing good support very close to your own units
Artillery is often seen as a firepower enhancement, but a better way to think about artillery is as if it's some kind of terrain or planetary condition you have some control over. It's best used to create an environment your enemy doesn't want to be in, causing them to leave positions, or causing them to not enter positions. Area denial. In that sense, they're best compared to a formation of Battle Armor hopping towards a hill or occupying an area, or to 'Mechs with AC20-sized guns. Your enemy tends to change his maneuvers based on those units, and that capability can be very powerful. It is a huge tactical advantage if you can execute your plan, while you're making your enemy change theirs.
One advantage artillery has to the two examples is that it has much higher 'mobility'. If that brace of Hunchbacks or Elementals is on one side of the battlefield, and you need some area denail on the other end, you're usually stuck. With artillery, it's just a matter of waiting for the new shells to arrive. In fact, artillery's ability to get to spaces you can't otherwise reach or affect is one of its best features.
So, that's the philosophy. The above does require that you deploy artillery wisely, and knowing what should be considered a poor use.
* Artillery needs numbers.
Many players look at artillery as some kind of big AC or LRM barrage. That's not totally inaccurate, but the key aspect to understand about artillery is that it's inaccurate even at the best of times. You need multiple barrels to be effective, outside of certain narrow conditions. It's therefore much better to have 4 Thumpers than it would be to have 1 Longtom, as a crude rule of thumb.
* Artillery needs forethought.
Regular BattleTech play tends to train the player in to assessing his current situation, and making the most out of it. Because of the delayed arrival time, artillery requires an ability to predict where the action will be 2 or more turns from "now". Try to estimate where the enemy will be if they continue their current advance at their current speed. (This is also why artillery is very effective against an enemy trying to hold a fixed position)
* Artillery should be used to modify your opponent's behavior
The fact that you're publicly targeting a location can be a great advantage if you use it well. Use bright D8's or D10s (anything but D6s) to mark target hexes, using the numbers on the dice to indicate how many more turns it will be before the shots land. It's good to make this obvious to your team (friendly fire sucks) but the real key here is the constant reminder your enemy has that those shells are inbound. Whenever those numbers count down, make sure your opponent is totally aware of it. You want him to leave, or never enter, thereby taking the terrain without using a single unit. And you can "hold" it by letting the rain continue until your own units can contest the location.
* Artillery requires solid documentation
One of the big obstacles with artillery is the paperwork. Find attached a document I use to keep track of when artillery is fired, when it arrives, and what ammo's going in. This does require that you keep a close eye on what turn it is, so use the Turn counter to keep track of that, incrementing it every time Initiative is rolled.
Targeting
When targeting, don't worry about the amount of damage you can get in 1 hex. Try think about your target as an area you're putting damage in to. The attached diagram indicates a targeting solution that makes it very probably that there will be damage 'inside' the box, even with a 11 to-hit. The teal stars indicate the target location for your 4 guns. If you have 8 guns, it pays to double up on each.
The 2 blue arrows indicate the 2 hexes (911 and 1012) that cannot be hit directly by a drifting shell in this diagram. This seems undesirable (and if you think so, adjust the targeting to 1110 and 1113 to correct), but this firing pattern creates a larger number of hexes where damage will be applied.
(Plus, it shows you which hexes to target in case you're aiming 6 guns)
And that's the business you're in: not maximizing the damage to a single hex, but maximizing the damage to as many hexes as possible.
Once targeted, it will make the wooded area inside the box extremely undesirable to the enemy. Additionally, it will also likely cause terrain reduction of the woods to Rough, if you play with those rules.
Or, if you're deploying smoke, it will very likely ensure your units will be safe in that area.
The math:
Hitting the target hex on an 11+ happens 3 in 36 times.
Missing it with a MOF of 1 happens 3 in 36 times.
Missing it with a MOF of 2 happens 4 in 36 times.
Missing it with a MOF of 3 happens 5 in 36 times.
Missing it with a MOF of 4 happens 6 in 36 times.
Having it drift in the ideal direction is a 1 in 6 chance.
So. The odds of your 4 attacks putting damage in hex 1011:
Attack on 0809: (4/36)*(1/6) + (5/36)*(1/6) = 0.0185 + 0.0231 = 4.16%
Attack on 0812: (3/36)*(1/6) + (4/36)*(1/6) + (5/36)*(1/6) = 0.0139 + 0.0185 + 0.0231 = 5.55%
Attack on 1111: (3/36) + (3/36)*(3/6) + (4/36)*(1/6) = 0.0833 + 0.0417 + 0.0185 = 14.35%
Attack on 1114: (4/36)*(1/6) + (5/36)*(1/6) = 0.0185 + 0.0231 = 4.16%
Ground total to get damage in 1011 = 28.2%
Seems low? Remember that the odds of doing damage to that hex when aiming for it is 'only' 16.7%, you just improved those odds by almost 70%.
And note the red-marked item: that's the beneficial math that kicks in when you aim next to a target: the drift die starts working in your favor.
Other aspects of this firing pattern:
The odds of creating damage in the hexes in between the 4 targets ('spokes' such as 0910+1010 and 0810+0811) is: 24.06%. Yep, just 4% less.
The actually targeted hexes (due to each have drift overlap with 2 others) are 30.55%
Putting all this together, it means you're creating probabilities for each hex, so the pattern provides the following:
4 Hexes: 28.2% (center of the box)
8 Hexes: 24.06% ('spokes')
4 Hexes: 30.55% (corners of the box)
And you'll be affecting the hexes just outside of this box decently as well, so you're creating a large zone where the odds of taking damage are all effectively better than a 9+ to-hit shot.
Pre-designated hexes
Using these rules (p.180, TO) dramatically increases the effectiveness of artillery, and should be included as much as possible.
There's a couple of strategies in selecting them. The best approach in my view is to focus on the area denial job. Each pre-designated hex created 7 hexes you can do damage to almost at will. Combined with a firing pattern, you can rapidly inflate the area you can reliably damage.
That's a great way to cover areas the enemy might use for their advance, or areas they might use defensively.
Just remember: the whole point of the doomsday device is lost if you keep it a secret. Sometimes, it can be to your advantage to let your opponent know that an incoming attack will not drift. Usually only effective if you want to prevent them from entering or staying in an area. But just as often, you don't mind relies on drift to keep his position safe, only to identify the hex as pre-designated.
Spotters
Spotters are an important part of artillery, as they allow you to increase your accuracy, which results in additional hexes you can hit on command.
To make the best use of this capability, it pays to keep a few infantry units occupied with nothing else. Spotting requires LOS both when the round is fired and when the round lands, something that takes multiple turns in the best of cases. Tying up main combat units with that job is expensive. Most recon units are also good for this; you don't loose much firepower, and unlike LRM Indirect, you don't have to worry about terrain and movement modifiers: you just need legitimate LOS to the target.
(This also means Smoke can be effective *against* spotters in some situations)
When using spotters, it may pay to put 2 units on the same hex. Assuming they're not 2 gunners, but in the 3-5 gunnery range, you don't lose quality, but you substantially reduce the likelihood that your friendly LOS to the target hex gets interrupted by hostile action or an unexpected Movement Phase event. (Sideslipping, etc). Vehicles work well in this capacity since they can share the same hex: makes it easier to ensure the same LOS.
Finally, don't be afraid to task one or two of your guns/launchers and spotters to ranging: specifically trying to get a shot-on-target on a hex you'd like as a pre-designated hex. You reduce your overall firepower, but improve accuracy. Plus, pre-designated hexes can be an on-going denial area, where the enemy will avoid them because they know how easy it is for you to land a shot there.
Damage Resolution
When using artillery, keeping track of damage can be tricky. My advice is to place a 1d10 or 1d12 (as long as it's different from a D6, and different from whatever die you're using as an arrival turn counter) in each hex that has something in it that's taking damage. The number on the die should indicate the number of 5-damage groups that must be resolved.
For example, if a hex containing a 'Mech gets hits by a Long Tom (25), while a Sniper(10 splash) and a Thumper(5 splash) land 1 hex away, the die would indicate an '8'.
Don't forget that the incoming attack comes from the direction of the artillery piece, though the splash damage comes from the hex where the damage landed. Whenever this is relevant, use multiple damage dice, and place them on the side of the target that reflects their origin.
For example, let's say the Long Tom hit on the Left Hand side, while the Sniper landed behind the 'Mech, and the Thumper landed in front, you'd place 3 dice total, a '5' on the left side, a '2' on the rear, and a '1' on the front.
If only a few shots landed close enough to do damage, you may be better off resolving the damage immediately, rather than using this method.
Smoke
Smoke is extremely powerful, especially if you allow the rules to have it act like Heavy Smoke (p.356). This makes it very probable that an area will deny LOS to the enemy, permitting an approach that would normally be extremely costly.
Additionally, it allows you to provide cover for units that are trying to hold a position, though this is a little trickier. Even a little drift may deny shots you were hoping to take; you may be better off using Smoke LRMs or SRMs.
Battle Armor
Battle Armor is very effective at the area denial role. They can stay effective despite losses, and between the ease with which they break LOS and get a 3+ to hit (most suits), they can be a major problem to dislodge, requiring several Mechs or vehicles to work together.
Or just a couple of your artillery tubes. The way Area Effect Damage works is very deadly to infantry, Battle Armor included. (Probably too deadly; but whatever). Use a firing pattern (see Targeting, above) either on a position Battle Armor is holding, or in front of their path of movement if they're heading to a location you don't want them to take. Their slow speed makes them vulnerable to artillery drift staying relevant.
Clearing Mines
Mines can often be ignored, unless they come in the 30-point density, or unless they're Active. Even 20-point fields can be a nuisance.
Artillery allows you to "recon" the area prior to getting there, or clear a known area. Presuming a direct-hit happened, you can consider the hex safe. (Yes, there's a 1 in 6 chance for the hex to still have active mines in it. A second hit reduces this to 1 in 36.)
Counter-battery fire
Surprisingly effective despite the mobility of artillery units, the real purpose here is that as the GM, it's a tool you can use to pull the plug on artillery if it's proving too unbalancing; sometimes its effects are difficult to predict.
You can either have this happen gradually, by removing individual artillery weapons, or all at once. (The latter'd be a fighter squadron bombing and strafing them to bits)
Artillery shouldn't be a suicide pact that kills the fun.
That's about it. As you can see, artillery can add an interesting game mechanic without becoming to overpowering. It gives you an ability that's difficult to duplicate with regular combat units.
Paul
