Advanced Aerospace Damage Model

[Alsadius]

The damage model for large naval vessels has always seemed over-simplified to me, but I didn't have any good ideas for how to make it more in-depth. Well, I had a brainwave. This is a more complex system than vanilla, and it is not compatible - it imposes a different set of construction rules, and requires different record sheets. But I think it's both more interesting and more accurate.

Basically, the idea is to add critical slots to large ships the same way that Mechs have them. Because the ships are so much bigger, the slots are also much bigger and more numerous. As well, to represent the defences in depth on a large ship, the damage model is changed somewhat - defences and criticals are now layered, with each individual critical slot having its own armour. This eliminates the need to use damage threshold rules, and instead allows for a more natural progression of damage to a ship.

Damage and Armour
Each of a WarShip's facings is divided into six areas, which are further sub-divided into six slots. Each facing, area, and slot has its own armour values. When a weapon damages a capital ship in combat, it always hits the nearest facing. To determine the slot hit, roll 1d6 to determine the area it hits, and then 1d6 to determine the exact slot. Damage is dealt to the armour on the slot first. When a slot loses all armour, the critical item in that slot(if any) is destroyed, and all further damage is dealt to the area's armour. When the area's armour is destroyed, the critical in that area(if any) is destroyed, and any further damage is dealt to the facing's armour. If the facing's armour is destroyed, then any further damage is dealt to the ship's SI, and if the SI is destroyed then the ship is destroyed.

When creating a WarShip, armour is always assigned equally between all slots. For each 100 points of armour assigned to a facing, the facing itself gets ten, each area gets four, and each slot gets two. (Keen observers will note this adds to 106. Just use 100, to keep the math simpler.)

Space stations and DropShips operate identically. JumpShips operate identically, except that they only have three areas per facing. Armour is assigned in 60-point groups instead of 100-point groups. (Again, this adds to 58, but just ignore it.)

As TW/SO armour amounts are not sufficient to armour ships properly in this system, increase the maximum armour amounts to the following:

• Spheroid DropShip: SI value x 15 tons
• Aerodyne DropShip: SI value x 18 tons
• JumpShip: SI mass / 2 tons
• WarShip: SI mass / 8 tons
• Station: SI mass x 2 tons

Critical Allocation
Each slot and each area may be given a critical if desired. Some items will be assigned to slots only, and some will be assigned to areas only. As with other construction rules, you cannot add more items to a ship than it has critical slots available. Weapons must be mounted on the appropriate facing corresponding with their fire arc(broadside-mounted weapons may be placed in either the fore or aft facings on the appropriate side). Destruction of any of the criticals listed below functions identically to a critical to that system in normal gameplay.

The following items are assigned to slots:

• Standard-sized weapons and ammunition. These must be assigned to slots. A slot on a DropShip or JumpShip may contain up to 6 standard-sized critical slots worth of standard-sized weaponry, while a WarShip's or station's slots can contain up to 24 standard-sized criticals worth. All weapons in a slot must be assigned to the same bay(but bays may cover multiple slots).
• Capital weaponry and ammunition. A slot on a JumpShip or DropShip may contain up to 500 tons worth of capital weaponry, while a slot on a WarShip or station may contain up to 2000 tons worth, all of which must be assigned to the same bay. Capital weapons must be assigned to slots first, but if an entire area is filled with weapons for a single capital weapons bay and there is still excess tonnage, the area critical may be used to contain the rest of the tonnage for the bay.
• Heat sinks. These must be assigned to slots. A slot on a DropShip or JumpShip may contain up to 12 standard-sized critical slots worth of heat sinks, while a WarShip's or station's slots can contain up to 60 standard-sized criticals worth. Note that only heat sinks added during construction must be placed - those given for free do not take up slots.
• Doors and docking collars. Each door or docking collar takes up one slot. All doors for a single bay must be in the same area.
• Engines. The station-keeping engine of a JumpShip or station takes up 2 slots. Each point of Safe Thrust on a DropShip or WarShip takes up 3 slots. These slots must be allocated aft, unless the aft is filled with engines, in which case they can be allocated to the aft-left or aft-right facings(or wing, on aerodyne DropShips).
• Grav decks. Each grav deck, regardless of size, takes up one slot on the left side of the ship and one slot on the right.
• Sensors. Each facing must have one slot devoted to sensors. In ships with a NCSS, this is doubled.
• Landing gear. In a DropShip, the landing gear takes up one slot aft.
• Jump Sail: In a JumpShip or WarShip, the jump sail takes up one slot in each of the aft-left and aft-right facings. (Sail integrity is reduced 50%, round up, if either is destroyed.)

The following items are assigned to areas:

• Capital Weapons: As specified above, capital weapons bays may occupy areas if they have already filled all slots in that area.
• Fuel: Fuel takes up one area, which must be the same area as the area with the most engine slots.
• K-F Drive: A JumpShip or WarShip's K-F drive takes up two areas at the nose and two aft. (Drive integrity is reduced 25%, round up, if any is destroyed.)
• Avionics: Avionics takes up three areas.
• CIC: The CIC takes up three areas.
• FCS: The FCS takes up three areas.
• Life Support: Life support takes up one area.
• Bays: Each bay takes up one area, which must be the same area as the slot for the door(s).
• Naval C3: A Naval C3 takes up one area.

(Other rarely used items, such as repair facilities, tug adaptors, and such may also appear. Use common sense there, I don't want to stat them all.)

Rule Changes
Fire control systems weight on WarShips is mostly there to prevent spam of small weapons, which this system does better. As such, that rule is eliminated.

Limits on numbers of doors, similarly, seems like an anti-spamming rule. There's now no cap except slots available.

The Called Shots rule is expanded significantly. Any standard-sized weapon may make a Called Shot against a single slot at a +4 penalty, or against a single area at a +2 penalty. Any capital-sized weapon may make a called shot against a single area at a +4 penalty.

Critical roll rules are changed as follows:

• Any roll that would normally be a critical(a natural 12, or any hit by a capital missile that exceeds the critical target number) will do damage to both the layer of armour it hits as well as the layer of armour below it. For example, if a ship with 30 capital-scale armour on a slot is hit by a NAC/20 that rolls 12 on its to-hit roll, it will deal 20 capital-scale damage to that slot and another 20 capital-scale damage to the area beneath it. If the slot was already destroyed, it will deal 20 to the area and 20 to the facing instead.
• Multiple criticals will do damage even deeper. If a Kraken had a 12 on its to-hit roll and an 8+ on its critical check roll, it would critical twice, and therefore deal 10 damage to each of slot, area, and facing.
• Any damage that would be dealt to a layer deeper than SI is instead doubled and applied to SI. If the Kraken above was firing into a slot and area that was already destroyed, then it would deal 10 to the facing, 10 to the SI, and the 10 that it would deal below SI instead becomes an additional 20 damage to the SI, for a total of 30.
• Attacks that are not intercepted by armour and hit SI directly are considered criticals on to-hit rolls of 10+ instead of 12+.
• Any levels of armour that are already destroyed are skipped - a critical that hits a slot that is in a destroyed area will deal damage to slot and facing.

I've attached a record sheet for use in this system. This is a single facing's record sheet, so a WarShip will have six of these as well as the main ship's sheet. It's a lot more paper, but I don't think it'll be significantly worse for actual play - the selection of hit location is as fast as ever, and crit rolls are reduced.

Thanks.

[Alsadius]

As a sample, I'll re-build the Star League-era McKenna under these rules:

Original stats:

Code: [Select]

Tech: Star League (2750)
Introduced: 2652
Mass: 1,930,000 tons
Length: 1,405 meters
Sail Diameter: 1,560 meters
Fuel: 1,600 tons (4,000)
Tons/Burn-day: 39.52
Safe Thrust: 3
Maximum Thrust: 5
Sail Integrity: 7
KF Drive Integrity: 37
Heat Sinks: 6,325 (12,650)
Structural Integrity: 95
Battle Value: 214,414
Armor
Fore: 200
Fore-Sides: 250
Aft-Sides: 250
Aft: 143
Cargo
Bay 1: Fighters (25) 4 Doors
Bay 2: Fighters (25) 4 Doors
Bay 3: Small Craft (16) 1 Door
Cargo (255,382.5 tons) 1 Door
DropShip Capacity: 6
Grav Decks: 3 (45, 45 and 75 meter diameters)
Escape Pods: 30
Life Boats: 30
Crew: 97 officers, 404 enlisted/non-rated, 78 gunners, 180 bay personnel
Ammunition: 500 rounds NAC/40 ammunition (600 tons), 30 Barracuda Missiles (900 tons), 20 White Shark Missiles (800 tons), 20 Killer Whale Missiles (1,000 tons)

Notes: Equipped with 1,603.5 tons of ferro-carbide armor and lithium-fusion batteries. Original stat block had 2 doors for the cargo and none for the small craft, changed to 1 and 1.

Weapons: Capital Attack Values (Standard)
Arc (Heat)Type Short Medium Long Extreme Class
Nose (440 Heat)
1 NAC/40 (41 rounds) 40 40 — — Capital AC
1 NAC/40 (41 rounds) 40 40 — — Capital AC
2 NL55 11 11 11 11 Capital Laser
FL/FR (700 Heat)
1 NAC/40 (41 rounds) 40 40 — — Capital AC
1 NAC/40 (42 rounds) 40 40 — — Capital AC
1 NAC/40 (42 rounds) 40 40 — — Capital AC
3 NL55 17 17 17 17 Capital Laser
2 AR10
(7 KW, 7 WS, 10 B) * * * * Capital Missile
LBS/RBS (2,700 Heat)
4 Heavy NPPC 60 60 60 60 Capital PPC
4 Heavy NPPC 60 60 60 60 Capital PPC
4 Heavy NPPC 60 60 60 60 Capital PPC
AL/AR (2,700 Heat)
4 Heavy NPPC 60 60 60 60 Capital PPC
4 Heavy NPPC 60 60 60 60 Capital PPC
4 Heavy NPPC 60 60 60 60 Capital PPC
Aft (900 Heat)
4 NL55 22 22 22 22 Capital Laser
2 AR10
(6 KW, 6 WS, 10 B) * * * * Capital Missile
1 NAC/40 (42 rounds) 40 40 — — Capital AC
1 NAC/40 (42 rounds) 40 40 — — Capital AC
1 NAC/40 (42 rounds) 40 40 — — Capital AC
1 NAC/40 (42 rounds) 40 40 — — Capital AC
* By Missile Type (Heat factored as Killer Whale)
Changes:
The new armour limit is 22,918.75 tons, but since the original McKenna only used ~44% of its armour cap, I'll do the same here. That yields 10,022 tons of armour, which I'll round off to 10,000. For ferro-carbide, that gives 8000 capital-scale armour points. We'll assign 1200 to the nose(=24 per slot, 48 per area, and 120 to the facing itself), 1500 to each side(=30 per slot, 60 per area, and 150 to the facing itself), and 800 aft(=16 per slot, 32 per area, and 80 to the facing itself). For a nose hit, you reach SI after doing 24+48+120=192 damage, as opposed to 200 for the original McKenna, but only if everything hits the same slot. As a result, it's generally better-armoured overall, but you'll start losing criticals sooner.

Critical space will need to be allocated. Let's count what we have.

There are 36 areas on a WarShip. Basic requirements take up 15 slots(1 fuel, 1 life support, 4 K-F, 3 avionics, 3 CIC, 3 FCS). Four bays will each take up an area. That leaves us with 17 areas that are unused, which could be allocated to capital weapons bays if needed.

There are 216 slots on a WarShip:

• 3 safe thrust is 9 slots for engines.
• One sensor per facing is 6 sensor slots.
• 10 doors and 6 docking collars is 16 slots.
• 3 grav decks take up 6 slots.
• The jump sail takes up two slots.

That leaves us with 177 slots. However, we haven't allocated heat sinks or weapons yet.

• There are 12 4xHNPPC bays, each of which will take six slots, for a total of 72.
• There are 12 NAC/40 bays, each of which will take up three slots, for a total of 36.
• There are 3 2xAR-10 bays, each of which will take up one slot, for a total of 3.
• There is one 2xNL-55 bay, which will take up two slots, for a total of 2.
• There are two 3xNL-55 bays, each of which will take up two slots, for a total of 4.
• There is one 4xNL-55 bay, which will take up three slots, for a total of 3.

That's 118 slots, leaving us 57 slots for heat sinks. 878 heat sinks are built into the McKenna, and this gives us 57*60=3420 slots for additional heat sinks. Using SHS we'd have 4298 heat dispersion, and using DHS we'd have 4036 heat dispersion(but we'd spend 2280 fewer tons doing it). For comparison, the original McKenna has 12,650 heat dispersion ability. That was somewhat overkill, but the reduced values created by these rules are too low right now.

Option 1: Knock a couple HNPPC bays off the ship. Those are the big heat hogs, and each one removed will drop the heat need by 900, and add 360 more slots for heat sinking. If we drop one HNPPC bay from each facing, we have a ship that generates 9940 heat firing everything and can sink 5738 heat. That's not quite as abundant as the original's heat sinks, but it's pretty good.

Option 2: Change my rule for heat sinks per slot. If it's 60 heat sinks(of any size) instead of 60 slots, the max becomes 8596 with DHS. That's not bad.

Option 3: Add a new piece of equipment, similar in principle to a radical heat sink or cooling pods. Maybe it would weigh 500 tons, take up an area, and let you sink 1000 heat once per battle(after which it's useless). This could mount 17 of them, which would let it keep firing for quite a while in practice.

I'm not 100% sure what's best here (I haven't playtested these, and it should be obvious now that I wrote the above post before creating this - downsides to house rules, tbh), but for sake of argument I'll go with #2.

We've added 8,396.5 tons of armour, and reduced heat sink weight by 2,027 tons, for a total weight increase of 6,369.5 tons. We'll just take that out of cargo, so it's now 249,013 tons of space.

Allocating everything as needed, you wind up with the attached record sheet. The ship is a little tougher than it would be under the official rules, and a little worse on heat sinking, but it's basically the same. And I think it looks more fun to play, because you actually get the sense that it's a seriously tough battleship with layers of defences to tear apart.

[marauder648]

This..is a bloody good idea!  Really the whole WarShip rules and the like could do with a re-working.  Its pointedly absurd that a ship with 200k+ of cargo space for example has ammo constraints or that Mech scale weapons on such a behemoth would actually NEED ammo to even be counted.

The fluff of ships like the Atreius class always had me scratching my head for example. Here's a ship with over 160k tons of cargo space. Which as a Banana for scale is heavier than this thing

https://en.wikipedia.org/wiki/MS_Freedom_of_the_Seas

But the ship only has 10 rounds of autocannon ammo per gun.  It boggles the mind as to what the rest of the cargo was, is it 160k + of pies and hard wood furniture? Maybe its a huge amount of trampolines, or bricks..what else was that bloody cargo used for to have 10 rounds per gun O_o

That there's no integral AMS or anti-fighter weapons, and the crew requirements just get weird and strange as you add more to them.  The whole systems a mess.

But this..this is DAMN good!

[Daryk]

I don't think critical space limits really make sense on the scale of a ship.  If you're trying to limit weapons, then do that (which the current fire control rules do, if badly).

[Alsadius]

This..is a bloody good idea!  Really the whole WarShip rules and the like could do with a re-working.  Its pointedly absurd that a ship with 200k+ of cargo space for example has ammo constraints or that Mech scale weapons on such a behemoth would actually NEED ammo to even be counted.

The fluff of ships like the Atreius class always had me scratching my head for example. Here's a ship with over 160k tons of cargo space. Which as a Banana for scale is heavier than this thing

https://en.wikipedia.org/wiki/MS_Freedom_of_the_Seas

But the ship only has 10 rounds of autocannon ammo per gun.  It boggles the mind as to what the rest of the cargo was, is it 160k + of pies and hard wood furniture? Maybe its a huge amount of trampolines, or bricks..what else was that bloody cargo used for to have 10 rounds per gun O_o

That there's no integral AMS or anti-fighter weapons, and the crew requirements just get weird and strange as you add more to them.  The whole systems a mess.

But this..this is DAMN good!

 ;D

I think the intention of the giant cargo bays is to give them lots of cruising range and lots of spare parts for their support ships. For example, if you look into a Nimitz-class aircraft carrier, about 10% of their weight is fuel, which is impressive given that they're nuclear-powered and don't use fuel. The air group does, though, and keeping them supplied is a huge task. Munitions weight will be added to this, as will spare parts and food and the like. All that would be counted in cargo. But yes, the magazines on a lot of these ships are stupid. How does a NAC/10 have ammo that weighs no more than an AC/20, which does a fifth the damage, when the gun is 150x bigger? I didn't want to mess with weapon stats, so I let that be. But when I finally get around to posting my total aerospace re-work, I'll be dealing with that for sure. (As a kludge, just assume that there's reloads in the cargo bay, but they're not practical to move to the gun on short notice, so you need to re-arm between combats.)

Also, another inspiration for this was a discussion of how battleships were really used in WW2. The big guns were important on paper but often not the biggest concern in practice due to the rise of the carrier. What they were often valued for in practice, especially in the Pacific, was their AA firepower. However, the reason they were so good at it was that they were physically large, and thus could fit all the needed guns, as well as all the crew members to use those guns. (The thick armour didn't hurt either) See this post for a good description, and an impressive picture of just how crowded these ships got. Ironically, the rules I actually posted above don't have this effect - a battleship can't carry any more gear than a corvette. I thought of scaling slot capacity by ship size, but decided it was a bit too complex. I'm not sure if I want to change that or not.

I don't think critical space limits really make sense on the scale of a ship.  If you're trying to limit weapons, then do that (which the current fire control rules do, if badly).

It's more a limitation on surface area, more so. And it makes perfect sense, because the ship is as big as it needs to be, no more. There are real warships are as big as small WarShips, and they have real and important space and volume limitations. The limits are different - deck space is a much bigger problem for RL carriers than their equivalents in BT, while 18th century ships of the line had more broadside weapons than a BT battleship can handle. But the limits are there, and they always will be. A ship that's so big that you don't need to worry about limits is either a ship that's wasting a lot of steel for no good reason, or a ship where some clever admiral is going to retrofit it until it's full again.

Also, I'll ramble a bit on the changes I might want to make here.

• I changed the Called Shots rule a bit. I liked the idea of fighters getting in really close to shoot up the guns that are attacking them, but a +4 penalty means they'll need to be close in practice, and it fits the vanilla BT rule more closely.
• If I ever write this up as a stand-alone, the "106, but call it 100" rule will be changed to a mass allocation to put a slab of armour on a side. Same sort of rules, but less annoying to the mathematically inclined.
• I should probably drop SI weights a little bit to compensate for the fact that I just sextupled the armour a ship can carry.
• Areas are too abundant and slots are too precious at the moment. There should be more options to use areas for things - heat dissipation options, crew quarters, redundant systems, something. Blowing up an empty area just seems anti-climactic, so let's have people fill them up.
• Right now, if you blow up one slot in an area, and blow up the area itself, the other slots are still perfectly functional. I'm not sure if I like this or not. The only ideas I've had for changing it would slow down gameplay too much to be practical, though.
• I have no idea why I made the record sheet in Word. It should obviously be Excel. I should re-build it.

[Daryk]

The things that drive size on real ships (propulsion, flight decks, etc.) leave more than enough space for secondary systems.  I've served aboard both aircraft carriers and submarines.  Just because the crew spaces on the latter are cramped doesn't mean there isn't an abundance of space for equipment.

[Alsadius]

Fair enough, I'll defer to your first-hand experience there. But the critical space limits aren't the only part of this - it's also, in part, about putting weapons in more vulnerable locations to make "crits" play more of a role. Also, it's about the fact that most canon battleships can blow each other up in a single round twice over(A McKenna's broadside is over 500 damage, which seems ludicrous to me given that its facing armour is less than half that at best).

[Vition2]

I've really only done a quick once-over, but first impressions:

I like it, it makes the warships feel more like age of sail warships, which is something that I think lends itself well to the setting.

I won't say it's perfect, there are some aspects of the armor distribution system and weapons systems that are still somewhat problematic - 24 standard sized weapons may still be too much per "bay" and a question about how you would apply some of these limitations to sub-capital weapons?

Lastly, a suggestion: One thing I'd like to see, is making capital and sub-capital missiles more interactive, rather than just outright destroy or degrade their potential to hit.  It'd be nice if they had the potential to overwhelm AMS defenses, or to still have a small chance of actual impact regardless of the amount of AMS the target has.  We've seen in canon, weapons that seem to be intended to overwhelm AMS and other point defense weapons, even though few, if any, warships carry the appropriate levels of defenses for the need for such weapons.

[Alsadius]

I've really only done a quick once-over, but first impressions:

I like it, it makes the warships feel more like age of sail warships, which is something that I think lends itself well to the setting.

I won't say it's perfect, there are some aspects of the armor distribution system and weapons systems that are still somewhat problematic - 24 standard sized weapons may still be too much per "bay" and a question about how you would apply some of these limitations to sub-capital weapons?

Lastly, a suggestion: One thing I'd like to see, is making capital and sub-capital missiles more interactive, rather than just outright destroy or degrade their potential to hit.  It'd be nice if they had the potential to overwhelm AMS defenses, or to still have a small chance of actual impact regardless of the amount of AMS the target has.  We've seen in canon, weapons that seem to be intended to overwhelm AMS and other point defense weapons, even though few, if any, warships carry the appropriate levels of defenses for the need for such weapons.

24 slots worth of weapons, not 24 weapons. For example, a slot might be 3x LRM-20 with Artemis IV and 2 tons of ammo each. Not a bad point defence installation, but not the same as 24 LRM-20s would be. (Energy weapons can be stacked in pretty huge numbers, but that means you use a lot of other slots on heat sinks, so it'll probably balance out.)

Sub-capital weapons I've never really played with, so I'm not sure how I'd make them work. Probably following the same rules as capital weapons? They may be a bit light for that to feel like a fair usage, but IDK how best to fix that. I'll give it some thought.

AMS rules are bad, I'll agree. That's a separate problem, but one I'd like to see solved. I want to be able to put point defence on my ships without feeling like I'm deleting a whole weapon type from the game.