Warships and Sub-Capital Weapons

[AlphaMirage]

I will admit to not being super knowledgeable in the arcane Aerospace arts.  For my fanfic I was refitting the Clan's SLDF era Warships with arrays of Sub-Capital weapons instead of their cavernous cargo bays since these ships have such poor point defense.  I know TPTB don't like Warships but they did exist but there are some canon remnant vessels that might benefit. 

What is your opinion of Sub-Capital Weapons on Warships?  If TPTB brought them back (unlikely) would they incorporate all the things that make Pocket Warships so dangerous in order to protect themselves from that threat?

[Liam's Ghost]

The biggest complication to using subcapital weapons is logistical. Like capital weapons, you need a gunner for every single subcapital gun. If they're ammo based, you're also burning through ammunition at a faster rate and will need a larger supply.

So you're burning up more consumables if you go for a big number of sub capital weapons instead of a smaller number of capital weapons.

I still like them as secondary guns, though. A supplement to the main battery for use against smaller targets (you can use bracketing fire with them, and the penalty to hit fighters is lower by default).

Another option is a massive battery of small subcapital lasers or sub capital cannons for use in planetary bombardment. It lets you fine tune just how much fire you're dropping on a target.

[Vition2]

When I think about building a fleet, I like putting them on smaller ships - ships meant to focus on the peripheral elements of an enemy fleet/force.  So I put them on corvettes and destroyers so they can more effectively screen their larger brethren from fighters and dropships.

This allows larger and heavier batteries of capital weapons to be placed on cruiser and larger vessels, making them more effective in the wall - they don't have to waste weapon slots, and therefore, tonnage, on weapons intended to fight these smaller opponents.

Again though, this is with the idea of building an effective battle fleet which is intended to engage an opposing battle fleet.  Since warships built in the battletech universe (at least those in the more recent eras) are intended to be closer to stand alone forces, when I build warships with this paradigm, I build them similarly to Liam's Ghost - they are a secondary weapon system supplementing the larger capital weapons.

[monbvol]

The +3 instead of +5 for targets below 500 tons is a good way to beef up anti ASF firepower then how much fire control, quarters, and additional supplies subcapitals can allow you to absorb does create break even points.

Where these break even points are does vary a bit and it is important to remember the engagement ranges that each option presents.

[wundergoat]

Subcapital lasers in AAA mode are pretty excellent fighter defense.  They’re only +1 to hit ASF and reach out to far greater ranges with far more accuracy than standard weapons.  I personnaly like twin SCL/3 bays.

[Daryk]

Monbvol mentioned the natural limit to that strategy: fire control tonnage.  If you can only mount a certain number of weapons before incurring a mass penalty, it only makes sense to make each individual weapon as effective as possible.  That would generally drive smaller weapons on to smaller ships (that can't mount the maximum number of larger weapons).

[Alsadius]

Monbvol mentioned the natural limit to that strategy: fire control tonnage.  If you can only mount a certain number of weapons before incurring a mass penalty, it only makes sense to make each individual weapon as effective as possible.  That would generally drive smaller weapons on to smaller ships (that can't mount the maximum number of larger weapons).

In principle, yes. In practice, you have to get to fairly large ships before it's an issue. You don't want 100% subcap guns on a battleship, but they could be the dominant weapon on most capital ships ever launched with no meaningful difficulties. I just threw together a quick million-ton capital ship (3/5, 120 SI, reasonable fighter wing and cargo), equipped it with 20 heavy sub-cap cannons per facing, and it used up the mass just fine. No fire control mass required. Admittedly, that's the heaviest of the sub-caps, but still. It's also quite mass-efficient compared to capital guns, in addition to being able to massacre fighters by the zillion.

[Daryk]

At what range again?  That's the usual advantage of the bigger weapons (Extreme Range)...

[monbvol]

Extreme Range is pretty meaningless in terms of engaging ASFs thanks to +6 and ASFs being able to Evade.

[Vition2]

Even at long range it's very difficult to hit - ASF don't have weapons that can effectively fire back at you until they are withing capital medium ranges, so we can always assume they are evading.  You're looking at Gunnery 2, +4 Range, +5 smaller than 500 tons, angle of attack nose +1, evading +3, bracketing fire -3 = 12+ to hit (Capital lasers in AAA mode are at 13+ to hit).

So using medium range sub-capital weapons means you get much more reliable attack rolls Gunnery 2, +2 Range, +3 smaller than 500 tons, angle of attack nose +1, evading +3 (and +3 on the fighters' attack roll), bracketing fire -3 = 8+ to hit (sub-capital lasers in AAA mode are 9+ to hit, capital weapons are at 10+ to hit, and capital lasers in AAA mode are 11+ to hit.

Against dropships, its a different story, capital weapons are going to annihilate them at pretty much any range they can hit them at.

[The_Caveman]

If you want to kill fighters, use Barracudas.

Subcap cannons are for making DropShips feel important.

[Daryk]

At Extreme Range, you hit the ASF carriers, then run the fighters out of gas...

[Vition2]

If you want to kill fighters, use Barracudas.

At Extreme Range, you hit the ASF carriers, then run the fighters out of gas...

Let's let the enemy be smart too, guys.  Random PoS fighters aren't going to be thrown at a warship piecemeal.  They're going to be at least moderately effective and coming in as a squadron - if each fighter is armed with even a single AMS they're going to be able to take down as few as 12 barracudas before a single one potentially gets through, not to mention they are going to get an opportunity to shoot at the missiles with their standard weapons as well.  Next, how many capital missiles does it take to reliably remove a fighter from combat?... it's more than 1.  With this in mind barracudas and other capital missiles quickly start to become inefficient - they aren't bad for softening up the targets, but you aren't going to kill very many of them unless you are firing truly overwhelming firepower towards them.

As for target that ASF carrier... why would it even think about being near the fight?  That's what it's aerospace fighters are for.  After the fight it picks up whoever is bingo on fuel, or lets them rot if your side lost - that's the calculus of war.

[wundergoat]

If you want to kill fighters, use Barracudas.

Subcap cannons are for making DropShips feel important.

The problem with barracudas is that despite being very accurate and long ranged, they are actually pretty heavy due to their 30 ton/shot ammunition.  Their low damage also means to get strong AAA protection, you actually need a bunch of bundled launchers.  You need three barracudas to get the same ASF deleting firepower of a twin SCL/3 mount but the barracudas are almost 2.5 times the weight for only 10 volleys.

[The_Caveman]

if each fighter is armed with even a single AMS they're going to be able to take down as few as 12 barracudas before a single one potentially gets through

Wait, how much have they buffed AMS?! I want to see the math on this. 6 AMS under AT2 shouldn't be able to completely stop 1 Barracuda, let alone a dozen.

[The_Caveman]

The problem with barracudas is that despite being very accurate and long ranged, they are actually pretty heavy due to their 30 ton/shot ammunition.  Their low damage also means to get strong AAA protection, you actually need a bunch of bundled launchers.  You need three barracudas to get the same ASF deleting firepower of a twin SCL/3 mount but the barracudas are almost 2.5 times the weight for only 10 volleys.

Cuda has -2 to-hit and an instant crit roll whether or not it thresholds, which at 20 damage it probably will. That's worth more to me than 30 damage at +1. And weight, on a WarShip, for anything other than capital ballistics/ppcs and core components, is basically a rounding error. A hundred capital missiles are like 1/1000 the mass of a small WarShip.

[monbvol]

Wait, how much have they buffed AMS?! I want to see the math on this. 6 AMS under AT2 shouldn't be able to completely stop 1 Barracuda, let alone a dozen.

Each individual ASF's AMS can concentrate on how ever many Capital Missiles are aimed at the squadron.

So if each ASF has one AMS it is able to knock down as many Barracudas as they have shots of AMS ammo.  Yeah it is pretty ridiculous in how easy it is to make capital missiles a non-issue.

[Vition2]

Well, it's technically an advanced rule laid out in SO (pg 97).  And is partially due to the (imo) idiocy of rounding values.  Each AMS does 3 points of damage, so a squadron of 6 will do 18, or 1.8 capital damage rounded to 2 capital damage, destroying a barracuda (note that  barracuda does 2 capital scale damage, not 20 standard damage, which is a stupid distinction).  An AMS can fire once at as many capital missiles it has it's AMS pointed at and has ammo and heat capacity for.  So a squadron of 6 ASF, using spheroid AMS with only 1 ton of ammo for it, and 12 sinked heat capacity will be able to take down 12 barracudas.  A typical clan star, similarly defended, would be able to take 24 white sharks in a single turn - assuming they have 24 heat they can sink.

In addition to this, standard-sized weapons can also be fired at incoming missiles, though they only get one shot per weapon.

Edit: I'll add that if I were to build an actual fighter intended for combat against warships, first it'd be clan (because Raven...meh), it'd probably have 2 AMS, and at least 2, maybe 3 tons of ammo, with the capacity to sink a lot of heat, probably close to 40, maybe a fair bit more, depending on the rest of the weapon loadout.  My "Heavy Bombers" would be 90 tons, while "heavy dogfighters" would be 70, with smaller versions of each at 60 and 50 tons.

Edit 2: If I were to be a gamist, that clan star with 1 AMS each and 1 ton of ammo, could actually take down 48 barracudas in a single turn... an extra ton of ammo each and they might be able to reach 96 depending on heat capacity.  Just to math that out for you, that's 5 fighters' AMS per barracuda doing 1.5 rounded to 2 capital damage killing the missile.  It actually makes me a bit disgusted to point that out, but appears to be legal in the rules.

[wundergoat]

I could have sworn that AMS engaged each missile bay attack as one unit but now that I go back and look at questions, I see that it is per missile. 

I remember something about the AMS bay killing as many missiles in the attack as it could, applying the TH# penalties to the next, and the remainder continuing on their merry way.  Did this change at some point?  I've been away for a while.

[Vition2]

IIRC, there was some supposition around that, but when the clarification was passed down, that fell by the wayside.  I think the assumption before the ruling was made was what you were thinking wundergoat, but ought to have never been the case.

[The_Caveman]

Yet on a 'Mech, an AMS can only engage one missile attack.

Yeah, that's a bad rule...

Edit 2: If I were to be a gamist, that clan star with 1 AMS each and 1 ton of ammo, could actually take down 48 barracudas in a single turn... an extra ton of ammo each and they might be able to reach 96 depending on heat capacity.  Just to math that out for you, that's 5 fighters' AMS per barracuda doing 1.5 rounded to 2 capital damage killing the missile.  It actually makes me a bit disgusted to point that out, but appears to be legal in the rules.

And were I to be a gamist, I wouldn't agree to using the optional rule that lets AMS engage cap-missiles ;)

[Vition2]

It's an abstraction based on the full-minute turn rather than the 12-second turn at the battlemech scale.  Not an argument that it's a bad rule, just an explanation.

In my own house rules (which I've never actually played and am constantly revising), capital missiles and their interactions with AMS are one of those areas that I'm always working on.  Unfortunately a lot of it ends up adding even more rolls to the game, and there are already more than there needs to be, imo.

[monbvol]

Yeah Capital Missiles are a tricky beast to solve reasonably well.

On the one hand the low damage they do without modification is pretty trivial but the criticals they can generate will add up pretty quickly.

Put an Asset Management Warhead in a Barracuda though and suddenly it becomes quite welcome for capital missiles to be so trivialized.

[The_Caveman]

It's an abstraction based on the full-minute turn rather than the 12-second turn at the battlemech scale.  Not an argument that it's a bad rule, just an explanation.

But this is a case of some animals being more equal than others. Why does the AMS and only the AMS get to attack multiple times? Why not machine guns, ultra autocannons, pulse lasers, etc. ? An AMS is just a machine gun with fancy targeting hardware, after all. Not to mention it blows the effectiveness of a minor defensive system with trivial weight out of proportion to the extent of making it required equipment as soon as it becomes available.

No, somebody on staff didn't think this through.

[Alsadius]

But this is a case of some animals being more equal than others. Why does the AMS and only the AMS get to attack multiple times? Why not machine guns, ultra autocannons, pulse lasers, etc. ? An AMS is just a machine gun with fancy targeting hardware, after all. Not to mention it blows the effectiveness of a minor defensive system with trivial weight out of proportion to the extent of making it required equipment as soon as it becomes available.

No, somebody on staff didn't think this through.

In-character, it's probably due to that fancy targeting system you mention.

Out of character, it's because an AMS that could only fire once would be kind of useless in WarShip-scale missile defence, especially given the numbers that had previously been installed on existing canon designs. They wanted to make it good, and overcompensated. And to be fair, on canon units AMS is perfectly balanced. It's only in custom unit construction that it gets obscene.

[The_Caveman]

In-character, it's probably due to that fancy targeting system you mention.

Out of character, it's because an AMS that could only fire once would be kind of useless in WarShip-scale missile defence, especially given the numbers that had previously been installed on existing canon designs. They wanted to make it good, and overcompensated. And to be fair, on canon units AMS is perfectly balanced. It's only in custom unit construction that it gets obscene.

Except the example upthread of fighters walking through a dozen Barracudas at a time only needs one AMS per fighter, which any canon design that mounts it satisfies when used as a squadron. Player designs going overboard just make the problem worse.

Anything can be rationalized with fluff, but this rule is both inconsistent and a balance problem. The whole point of capital missiles is they efficiently kill small craft. That's supposed to be their niche.

If they wanted a capital-grade CIWS they should have just invented one.

[Alsadius]

Except the example upthread of fighters walking through a dozen Barracudas at a time only needs one AMS per fighter, which any canon design that mounts it satisfies when used as a squadron. Player designs going overboard just make the problem worse.

Anything can be rationalized with fluff, but this rule is both inconsistent and a balance problem. The whole point of capital missiles is they efficiently kill small craft. That's supposed to be their niche.

If they wanted a capital-grade CIWS they should have just invented one.

I agree that a capital AMS would have been a much better design decision. My comment about balance was in reference to WarShip design, not fighters (which, as you say, have some obvious issues with the AMS rules).

That said, only the Barracuda is a fighter-killer. The White Shark, Killer Whale, and Kraken are all ship-killers, not AA.

[monbvol]

I agree that a capital AMS would have been a much better design decision. My comment about balance was in reference to WarShip design, not fighters (which, as you say, have some obvious issues with the AMS rules).

That said, only the Barracuda is a fighter-killer. The White Shark, Killer Whale, and Kraken are all ship-killers, not AA.

Sure the Barracuda gets the whole -2 to make it more accurate but the White Shark and Killer Whale still have use as AA thanks to them not taking the +5 against targets under 500 tons either.

So they kind of solve the problem.  Sort of.

Ultimately yes it would have been so much better to have put in a capital AMS.

[Alsadius]

Sure the Barracuda gets the whole -2 to make it more accurate but the White Shark and Killer Whale still have use as AA thanks to them not taking the +5 against targets under 500 tons either.

So they kind of solve the problem.  Sort of.

Ultimately yes it would have been so much better to have put in a capital AMS.

Oh, wow. How on earth did I not know that rule? I thought they got the same +5 vs small targets as capital guns, and Barracudas just had -2 to hit in addition to that for +3 net. Barracudas are pulse Thunderbolt-20s, with improved TAC rolls and capital range? Impressive.

[Jellico]

AMS on a small craft only fires once a turn.
AMS on a large craft can fire multiple times a turn.

On a evasion related note don't forget that large craft can Evade too.
Outside 20 hexes the large craft should stay stable and the ASF should evade making it immune to everything bar Barracudas.
Under 20 hexes both should evade because a combination of evasion and ECM makes the large craft immune while it can now get viable to-hits on the ASF.
Under 14 hexes the large craft should evade and the ASF should stay stable so it can actually use its weapons.
It is worth pointing out that a ASF has to get to 14 hexes to be able to use an Alamo.
The above basically holds true with 4/5 crews. With better gunners YMMV.

[Daryk]

Can Naval Laser Bracket Fire in AAA mode?

[monbvol]

Oh, wow. How on earth did I not know that rule? I thought they got the same +5 vs small targets as capital guns, and Barracudas just had -2 to hit in addition to that for +3 net. Barracudas are pulse Thunderbolt-20s, with improved TAC rolls and capital range? Impressive.

Been that way since at least Battlespace.

AMS on a small craft only fires once a turn.
AMS on a large craft can fire multiple times a turn.

On a evasion related note don't forget that large craft can Evade too.
Outside 20 hexes the large craft should stay stable and the ASF should evade making it immune to everything bar Barracudas.
Under 20 hexes both should evade because a combination of evasion and ECM makes the large craft immune while it can now get viable to-hits on the ASF.
Under 14 hexes the large craft should evade and the ASF should stay stable so it can actually use its weapons.
It is worth pointing out that a ASF has to get to 14 hexes to be able to use an Alamo.
The above basically holds true with 4/5 crews. With better gunners YMMV.

I don't remember a provision of actual proper AMS being limited in that fashion on small craft.

Can Naval Laser Bracket Fire in AAA mode?

It is expressly prohibited.

[Daryk]

Rog, thanks... it's been a while since I looked at those rules...

[The_Caveman]

Sure the Barracuda gets the whole -2 to make it more accurate but the White Shark and Killer Whale still have use as AA thanks to them not taking the +5 against targets under 500 tons either.

So they kind of solve the problem.  Sort of.

Ultimately yes it would have been so much better to have put in a capital AMS.

Cudas are the fighter-killers. Sharks and Whales, IMO, are best suited to busting heavily armored small craft and micro-DropShips which have the armor to tank a 20-damage hit without thresholding. Kraken-T is the closest thing to a dedicated ship-killer since it can threshold small WarShips and assault DropShips.

I'm not quite sure where this leaves subcapital missiles. They don't offer enough of a weight savings to combat their short range relative to their full-size counterparts, and DropShips can carry both. Manta Rays seem like they'd be worthwhile as a last-ditch "kill it now" defense against space bombing and kamikaze attacks by fighters. But you need 14 grouped launchers to hit the magic 70 fire-factor cap, so for anti-ship work they remain inefficient.

Since the Piranha lost its to-hit bonus it no longer seems worth the trouble. Sure the missiles weigh a third what Barracudas do, but is your WarShip really going to last those 50 turns to use them up?

[Jellico]

I don't have my books handy so the specifics will be rubbery...

All capital and subcapital missiles get a crit chance every time that they hit something. From memory...

Barracuda 12
Killer Whale 10
White Shark 9
Kracken 8

So Barracudas are the AA option. -2 to-hit and by doing 20 damage it is an immediate crit chance (maybe just for squadrons. can't remember, but 20 will threshold most ASF armour) in addition to the natural 12 it gets.

With 40 damage Killer Whales are the damage option while the White Shark is the crit option.

Krackens are unwieldy and reward you for effort. I am not even sure that they can target ASF.

I forget the critical chances for sub capital missiles.

Piranhas are most useful because of their range. They don't get a natural crit chance but 30 damage means that they will threshold ASF at will.

Stingrays are middling. At least they reach beyond 14 hexes to provide a layer of defence outside nuke range. That is why they ended up on the Leviathan III. Also they can still use way points so the mounts int the broadsides can cover 360 degrees.

The final two missiles are sucker punches under 14 hexes. Brutally powerful but they allow your enemies into effective range. The Isegrim uses its acceleration to get in close and drop a massive amount of damage into a target at very low to-hits.

[Jellico]

Now I have my books.

Strat Ops. P97. AMS: 2nd Paragraph "Fighter AMS may only be used once per turn."

Total Warfare. P239 Capital Missile Critical Hit Table
Barracuda 11+
White Shark 9+
Killer Whale 10+
Kraken 8+


Tactial Operations. P344 SUBCAPITAL MISSILE CRITICAL TABLE
Piranha N/A
Stingray 12+
Swordfish 11+
Manta Ray 10+

Strat Opd P32. Fighter Squadron Critical Hits and Fatal Threshold Damage
"Standard critical hits against a fighter squadron may occur in
the following two ways:
• Any single attack that destroys 2 points of a fighter’s armor
(at least 15 points of standard-scale damage).
• A natural 12 result on the dice roll."

Total Warfare P238-239 Critical Hits
"To determine if a unit takes a critical hit, roll 2D6 whenever one
of the four conditions below is met."
"Damage Thresholds:"
"SI Damage"
"Lucky Hits: Any successful to-hit roll that is also a natural 12"
"Capital Missiles: Every hit with a capital missile or missile
bay that strikes armor may inflict a critical hit, even if the
attack did not damage SI or meet any other standard critical
hit requirement." "A player makes only one critical roll per missile bay."

I am putting all this critical hit stuff down because it is important. To kill a Stingray squadron you need to do 180 damage... 6 times. So 1080 points. Because the exact ASF you hit is random you aren't going to start getting kills and degrading fire power till you have done about 500 points of damage.
OTOH Crits are relatively easy to get. A pair of large lasers will do it. And they start degrading firepower immediately.
If you do big chunks of damage, you get into Fatal Threshold territory. A Stingray has a Fatal Threshold of 50 meaning that if you do 110 damage the Stingray will die 50% of the time. Capital Missiles are good at that. That is a 4 x Piranha bay that has a 50% chance of killing a fighter with 200 points of armour in a single turn at 40 hexes. Not bad hey.

[Daryk]

Wait a second... does that "Crit on a 12" bit apply to ground to air fire too?  How have I missed that all these years??

[Vition2]

Strat Ops. P97. AMS: 2nd Paragraph "Fighter AMS may only be used once per turn."

Thanks for the reference, I was missing this even though I re-read the section 3-4 times after you first said this.

It makes me wonder about making a 2-400-ton "dropship" built to provide AMS defense for aero squadrons.  Hopefully the cost ends up being somewhat prohibitive - and is there anything about dropships not being allowed to be carried as cargo? (dropships as cargo is an area I specifically tend to ignore, due to the potential for abuse, and not even wanting to go there... usually  :D)

[Daryk]

Dropships as cargo is a third rail even for TPTB.  I'll link the rules question where Xotl basically said "don't hold your breath" for an answer when I find it again.

[Daryk]

Well, that took rather less time than I thought it would!

https://bg.battletech.com/forums/index.php?topic=63631.0

[The_Caveman]

Dropships as cargo is a third rail even for TPTB.  I'll link the rules question where Xotl basically said "don't hold your breath" for an answer when I find it again.

Do we really want a Potemkin being able to haul 130-odd Unions around? Nevermind a Leviathan...

[Vition2]

https://bg.battletech.com/forums/index.php?topic=63631.0

Technically that's specific to repair bays, but I'd be willing to expand that to cargo bays in general.  The answer given implies that, according to a strict reading of the rules, it's allowable - but it really shouldn't be allowed.

Do we really want a Potemkin being able to haul 130-odd Unions around? Nevermind a Leviathan...

From a logical standpoint a big union - which itself carries 12-14 largish units inside - would be significantly more difficult to carry than something that is only about 1/3rd larger than the physical size of a small craft - which have specific launch and holding areas.

I can easily see the potential for abuse here, but there are some areas where it would make sense for it to be okay - or at least a thing that isn't a dropship but has the size and in-system military capabilities of one but is more difficult transport to different systems.

...And now it seems like I'm arguing that monitors should be okay, and I'm not really in that camp.

To the OP - sorry for taking your question so far off topic, but this seems to happen a lot on these forums.  :-[

[monbvol]

Thanks for the reference, I was missing this even though I re-read the section 3-4 times after you first said this.

It makes me wonder about making a 2-400-ton "dropship" built to provide AMS defense for aero squadrons.  Hopefully the cost ends up being somewhat prohibitive - and is there anything about dropships not being allowed to be carried as cargo? (dropships as cargo is an area I specifically tend to ignore, due to the potential for abuse, and not even wanting to go there... usually  :D)

I myself have read that section as being specific to the other Point Defense Weapons, not AMS proper.  But going back it does actually include AMS proper for Small Craft.

Which seems to give subcapital missiles something of an interesting role, use them first to saturate Point Defense then use the full Capital Missiles as finishers.

[Jellico]

Why go DropShip when you can go Small Craft. One day they will let me revisit TRO3057 and I will put AMS on a Star League NL42. That will fix the "no SL AMS" meme.


Saturating point defence with Sub Caps doesn't really gel. Piranhas have the damage of a White Shark making the quite efficient. The other missiles have a range envelop of an LRM or worse. Why use the 50 point weapon as a distraction when you can use a 5 point weapon.