CT LBB:2 Starship Armor solution

[ddamant]

The following is a possible solution to making allowance for something that is of course lacking in LBB:2, Starship Armor.

The approach is similar to LBB:1 combat. Either a weapon hits and penetrates or it does not. Ablative armor or damage reduction never really appealed to me since in my experience they simply slow down games with more die rolls.

Armor itself is purchased per High Guard rules. No changes there.

In LBB:2, when a starship is hit in combat throw 8+ to avoid a damaging hit. The armor value is applied as a +DM.

Some weapon types produce negative modifiers. Some individuals have produced cross-over versions of weapons found in High Guard or custom designs of their own. Those weapons are listed for completeness.

Focused Force Missile: -1/0 (contact vs proximity detonation)
Nuclear Missile: -4/-2 (contact vs proximity detonation)
Fusion Missile: -6/-3 (contact vs proximity detonation)
Barbette (dual laser/energy/single particle beam): -1
50 ton bay (laser/particle/energy): -2
100 ton bay (laser/particle/energy): -3

This system allows for the avoidance of some damage while keeping things simple. The DM's are of course subject to modification. Missiles (aka torpedoes) are intended to be the primary ship killers in my universe. Weapons can potentially have a high penetration value against armor without increasing damage, so modify at your leisure. One could also incorporate weapon tech levels: when weapons reach a certain tech level (like in High Guard) they gain +1 to penetrate armor.

The idea is to keep things simple without overly complicating the game.

 

[McPerth]

A simpler way would be to to use the Armor factor (full or divided by 2 or 3) as negative modifier to hit, giving some wepons modifiers to overcome this negative one (it never could be positive).

I see it more consistent with character combat armor treatment, and only needs a single dice roll instead of two, but I guess both ways would achieve similar results...

 

[ddamant]

That was my first idea actually. The issue that came up is how to handle missiles? They do not roll to hit. They intercept and either contact detonate or proximity detonate. Damage is similar to a fireball in Dungeons and Dragons: pain is coming, how much depends on your saving throw result.

Perhaps some sort of dual approach, with beams getting a DM to hit and missiles requiring the ship to throw to save vs damage? Or, perhaps armor automatically reduces the number of hits per missile based on the armor value?

 

[Timerover51]

That was my first idea actually. The issue that came up is how to handle missiles? They do not roll to hit. They intercept and either contact detonate or proximity detonate. Damage is similar to a fireball in Dungeons and Dragons: pain is coming, how much depends on your saving throw result.

Perhaps some sort of dual approach, with beams getting a DM to hit and missiles requiring the ship to throw to save vs damage? Or, perhaps armor automatically reduces the number of hits per missile based on the armor value?

If a missile in the vacuum of space is set for proximity detonation, the only damage that is going to be done is by warhead fragments, but remember that they will have a velocity vector in the direction the missile was traveling, as well as a sideways velocity vector. There will be no blast effects. I would assume that such a missile would have a controlled fragmentation warhead, but, based on the fact that in Classic, it takes 1000 points of damage to punch a man-size hole in an internal pressure bulkhead. you will need some reasonably good-sized fragments to penetrate a ship's outer hull. The question will then be, did the fragment penetrate the hull, or just a fuel tank? In addition, I would assume that the ship is going to have a double hull, with insulation between the inner and outer hulls, to keep the interior of the ship from having severe cooling problems.

Given the very small size of Classic, 50 kilograms total, about the size of a Sidewinder AAM, the warhead is going to be fairly small, which would work against a proximity-fuzed missile, and require a direct hit.

 

[McPerth]

That was my first idea actually. The issue that came up is how to handle missiles? They do not roll to hit. They intercept and either contact detonate or proximity detonate. Damage is similar to a fireball in Dungeons and Dragons: pain is coming, how much depends on your saving throw result.

Perhaps some sort of dual approach, with beams getting a DM to hit and missiles requiring the ship to throw to save vs damage? Or, perhaps armor automatically reduces the number of hits per missile based on the armor value?

Against missiles, just apply the modifier (be it full or partially) to the roll for hits. As different missiles do different number of hits, it should work too...

 

[ddamant]

The small size of Traveller missiles compared to the tactical ranges that they are supposed to operate in has always bothered me.

 

[Timerover51]

The small size of Traveller missiles compared to the tactical ranges that they are supposed to operate in has always bothered me.

Given the size, they basically have no warhead, and have to depend on a direct hit to do damage. If fired from directly behind by a pursuer, the best defense would be to eject a concentration of ball bearings behind your ship, and let the missile run into them. The ball bearings would also not do the pursuing ship any good as well. They would make that area of space a tad dangerous for quite a while, unless policed up.

 

[ddamant]

GURPS Traveller has some different rules for missiles which I think I will incorporate. There are two types: standard and heavy (military grade only, I would call them torpedoes). Standard TL 12/13 missile racks launch 250mm diameter missiles which weigh 500 lbs with a 3.5 meter length. Heavy missiles have a diameter of 500mm, are 5m in length and weigh 2000 lbs. Their damage is roughly 2.5 times that of a standard missile. I would rule that heavy missiles are launched from 5-ton CT Missile Barbettes (with one launcher in each barbette) or 50/100 ton bays (launching 3 and 6 missiles respectively). GURPS missiles travel at 6G for 3 rounds, operating as a discretionary burn CT Traveller missile. Damage would be on par with Book 2 rules, with regular missiles doing D6+2 hits and heavy missiles doing 2D6+4 hits.

Nuclear/Fusion warheads would do more damage, certainly enough to eliminate most small ships. To keep things simple, just double the damage and add a die of radiation damage as well.

Note: TL 9-11 missiles travel at 5G. TL14 missiles can pull 8G. TL15, 10G.

 

[McPerth]

Given the size, they basically have no warhead, and have to depend on a direct hit to do damage.

And yet they are told to be proximity fused:

From TTB, page 79/LBB2 page 32 (bold is mine):

Ordnance which impacts a target in a movement phase, and which then survives anti-missile fire, detonates in the ordnance launch phase. This detonation will inflict 1 to 6 hits depending on the range at detonation.

If fired from directly behind by a pursuer, the best defense would be to eject a concentration of ball bearings behind your ship, and let the missile run into them. The ball bearings would also not do the pursuing ship any good as well. They would make that area of space a tad dangerous for quite a while, unless policed up.

As Sandcaster fire?

 

[aramis]

They are apparently modeled after the Aim-9 Sidewinder - 3.08m, x 12.7cm, 85 kg... the CT missile is 2.5m, 10cm, and 50kg...

The AIM-9 is a "shotgun warhead"... it throws a 30° cone of shrapnel at terminal guidance command and never intentionally contact hits. (when it does, it's spectacular...)

The traveller missile sure looks like (mechanically) it's doing similar.

 

[Timerover51]

Based on the ANNIC NOVA, where about 200mm of steel require 20,000 points in damage from an energy weapon or cutting torch to breach, and Traders and Gunboats, where 1000 damage points from an energy weapon or explosives is required to punch a man-sized hole through a ship's bulkhead, I have drawn the following concept of bulkhead and hull thicknesses. This is supplemented by information on the thickness of submarine pressure hulls in World War 2 compared to crush depth.

Allowing for a scaling factor for increased difficulty cutting through thick steel, I would put the thickness of a ship's internal pressure bulkheads at about 20mm of high-tensile strength steel, or 0.8 inches approximately, while a .875 inch thickness of high-tensile strength steel, roughly HY-50, was good down to at least 900 feet prior to collapse. As a flat bulkhead would have a lower pressure rating than a circular submarine hull, this would still give a very high safety factor in case of explosive decompression.

Based on the Chamax adventure, the outer hull of the ship is not going to be that much heavier than an internal pressure bulkhead, so perhaps as much as 1 inch or 25mm of high-tensile strength steel. The fragments from a World War Two 20-pound fragmentation bomb are not going to penetrate 1 inch of high-tensile strength steel, based on the terminal ballistics data that I have. Now, that was a controlled-fragmentation bomb, using Composition B in the latter part of the war. Twenty pounds is 9 kilograms, an appreciable fraction of 50 kilograms. Now, you could design a multi-shaped charge warhead using something like the current 40mm High-Explosive Dual-Purpose round, which is credited with penetrating 40 to 50mm of steel armor, but that would again require a fair amount of mass, and the penetrations are going to be in the nature of pencil-size. That does assume that the ship does not have a double-hull, as would easily be possible. I am also not totally sure of the performance of a shaped-charge jet under vacuum condition, whether it would break up more quickly or not.

Overall, looking at the standard Classic 50-kilogram missile, I simply do not see it as that damaging, aside from a direct hit.

 

[kilemall]

Based on the ANNIC NOVA, where about 200mm of steel require 20,000 points in damage from an energy weapon or cutting torch to breach, and Traders and Gunboats, where 1000 damage points from an energy weapon or explosives is required to punch a man-sized hole through a ship's bulkhead, I have drawn the following concept of bulkhead and hull thicknesses. This is supplemented by information on the thickness of submarine pressure hulls in World War 2 compared to crush depth.

Allowing for a scaling factor for increased difficulty cutting through thick steel, I would put the thickness of a ship's internal pressure bulkheads at about 20mm of high-tensile strength steel, or 0.8 inches approximately, while a .875 inch thickness of high-tensile strength steel, roughly HY-50, was good down to at least 900 feet prior to collapse. As a flat bulkhead would have a lower pressure rating than a circular submarine hull, this would still give a very high safety factor in case of explosive decompression.

Based on the Chamax adventure, the outer hull of the ship is not going to be that much heavier than an internal pressure bulkhead, so perhaps as much as 1 inch or 25mm of high-tensile strength steel. The fragments from a World War Two 20-pound fragmentation bomb are not going to penetrate 1 inch of high-tensile strength steel, based on the terminal ballistics data that I have. Now, that was a controlled-fragmentation bomb, using Composition B in the latter part of the war. Twenty pounds is 9 kilograms, an appreciable fraction of 50 kilograms. Now, you could design a multi-shaped charge warhead using something like the current 40mm High-Explosive Dual-Purpose round, which is credited with penetrating 40 to 50mm of steel armor, but that would again require a fair amount of mass, and the penetrations are going to be in the nature of pencil-size. That does assume that the ship does not have a double-hull, as would easily be possible. I am also not totally sure of the performance of a shaped-charge jet under vacuum condition, whether it would break up more quickly or not.

Overall, looking at the standard Classic 50-kilogram missile, I simply do not see it as that damaging, aside from a direct hit.

Striker gives us a direct value- 336mm of steel, or likely some higher material tech equivalent at a thinner thickness.

Of course, an AIM-9 is not designed to punch through armor, it's for an entirely different kind of target. That being said, pellet shot at a velocity of 50 km per second, the result of 5G accel for 1000 seconds (assuming most people's understanding of what 5G5 means which I dispute) is not chicken feed.

Assuming just even 1kg of that warhead is impacting pellets, that's 1.25 gigajoules.

Which yields the energy of a 757 at 300 knots, and a bit short of the warhead of a TLAM-C.

https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)
http://www.projectrho.com/public_html/rocket/usefultables.php

We can figure the classic 1d6 roll is a bit more warhead, 2-3 kg, impacting.

So, not unreasonable extrapolation of kinetic potential. The fantasy part was always the propulsion in such a tiny packages.

 

[aramis]

The AIM9 has 22 G's for 2.2 sec... 48.4 G-sec. The Traveller missile has 200x the fuel duration under the 5G5 as 5G Max 5 g-turns total. Which I agree, is not how it should be read, but Don said it's how it is, and Don was the official errata man.

(I always read xGy as xG's for y turns.)

If it's a one-use gravitic drive... it's too cheap by far, but it would explain the idea of 25000 G-seconds of "fuel"...

 

[Timerover51]

Striker gives us a direct value- 336mm of steel, or likely some higher material tech equivalent at a thinner thickness.

Of course, an AIM-9 is not designed to punch through armor, it's for an entirely different kind of target. That being said, pellet shot at a velocity of 50 km per second, the result of 5G accel for 1000 seconds (assuming most people's understanding of what 5G5 means which I dispute) is not chicken feed.

Assuming just even 1kg of that warhead is impacting pellets, that's 1.25 gigajoules.

Which yields the energy of a 757 at 300 knots, and a bit short of the warhead of a TLAM-C.

https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)
http://www.projectrho.com/public_html/rocket/usefultables.php

We can figure the classic 1d6 roll is a bit more warhead, 2-3 kg, impacting.

So, not unreasonable extrapolation of kinetic potential. The fantasy part was always the propulsion in such a tiny packages.

I appears that you are using a stationary target for your figures. Also, you need to factor that velocity into the possibility of the fuzing not being close enough for the fragments to hit a ship prior to going past it. As for one kilogram of impacting pellets, I would suggest you do some calculating as the the size of warhead needed for those one kilogram of pellets to hit a ship from the side. Do you have any concept of the fragment pattern of a controlled-fragmentation warhead?

As for Striker's figures, I will make no comment. I will point out that in Classic LLB 3, Worlds and Adventures, missiles and missile launchers are a Tech Level 6 technology. Pulse lasers are a Tech Level 7 technology. Sand casters are a Tech Level 5 technology. Kindly demonstrate a current missile that can maintain thrust for 1000 seconds, and the missile must weight no more than 50 kilograms.

 

[kilemall]

The AIM9 has 22 G's for 2.2 sec... 48.4 G-sec. The Traveller missile has 200x the fuel duration under the 5G5 as 5G Max 5 g-turns total. Which I agree, is not how it should be read, but Don said it's how it is, and Don was the official errata man.

(I always read xGy as xG's for y turns.)

If it's a one-use gravitic drive... it's too cheap by far, but it would explain the idea of 25000 G-seconds of "fuel"...

I agree with Don's interpretation for missile performance as a matter of game mechanics and role, while simultaneously knowing even the conservative 5G one turn interpretation is ridiculous by current technology (making the me-and-Don camp 5x as ridiculous I suppose).

Of course one has 'the future' and handwaving for gravitic missiles or some super ion engine, but where it goes really wrong is asserting similar performance for TL8 missiles, where you don't have the excuse of multiples of performance that might theoretically be developed.

TL is too advanced too early, and likely not advanced enough later.

 

[kilemall]

I appears that you are using a stationary target for your figures.

Of course, its a back of the envelope for example. You would probably use the vee rules in SS3 to deal with it. I'm just putting the point out there that space is different and kinetic impact is a Really Ugly Thing.

That's why any captain not running Auto-Evade is begging for disaster, just some debris and space junk can end Travelling real quick.

Also, you need to factor that velocity into the possibility of the fuzing not being close enough for the fragments to hit a ship prior to going past it. As for one kilogram of impacting pellets, I would suggest you do some calculating as the the size of warhead needed for those one kilogram of pellets to hit a ship from the side. Do you have any concept of the fragment pattern of a controlled-fragmentation warhead?

Yes, I always imaged that the missiles were detonating on a lead of just a few hundred meters at worst, so about the same distance and pattern for AAMs.

SS3 has those warheads in multiples of 10kg, I am assuming a lower percentage of HE to get a tighter pattern but still most of the pellets are going to miss.

As for Striker's figures, I will make no comment. I will point out that in Classic LLB 3, Worlds and Adventures, missiles and missile launchers are a Tech Level 6 technology. Pulse lasers are a Tech Level 7 technology. Sand casters are a Tech Level 5 technology. Kindly demonstrate a current missile that can maintain thrust for 1000 seconds, and the missile must weight no more than 50 kilograms.

You darn well know there is no such thing, and a bit strange to me you would trot out this one when I have already acknowledged the fantasy aspect of Traveller missiles by current technology.

As an exercise I was using the S-300 missile as about the right size for the High Guard bay missile. Much more relative juice to warhead, but still not even in the ballpark.

 

[Timerover51]

Just a question. Why are you using streamlined missiles dependent upon fins for atmospheric maneuvering when in space you are in a vacuum?

An exo-atmosphere missile is much more like to resemble a miniature Lunar Lander. Then there is also the problem of sensor range with a small radar antenna.

I am also not sure why if Sandcasters exist, there are not equivalent Radar Decoys, or even something as simple as Chaff?

The original post referred to LLB 2 starships, by Marc Miller, not Striker, by Frank Chadwick.

I will drop the discussion of the warhead, but simply point out that you have 50 kilograms to work with, for power plant, whatever that might be, control system, whatever that turns out to be, sensors and guidance system, and warhead.

 

[aramis]

Sandcasters are explicitly shotguns. The logic fail is "Why does a sandcaster not work as a ship-to-ship weapon and/or movement hazard..."

 

[kilemall]

Just a question. Why are you using streamlined missiles dependent upon fins for atmospheric maneuvering when in space you are in a vacuum?

An exo-atmosphere missile is much more like to resemble a miniature Lunar Lander. Then there is also the problem of sensor range with a small radar antenna.

I am also not sure why if Sandcasters exist, there are not equivalent Radar Decoys, or even something as simple as Chaff?

The original post referred to LLB 2 starships, by Marc Miller, not Striker, by Frank Chadwick.

I will drop the discussion of the warhead, but simply point out that you have 50 kilograms to work with, for power plant, whatever that might be, control system, whatever that turns out to be, sensors and guidance system, and warhead.

I presume a logical reason would be it's streamlined so it can fired into or out of atmosphere. Secondarily to fit extant systems and presumably the atmo capability is enough of a feature to be standard.

In reality, I expect a game entertainment decision because of aesthetics and what people expect. Missiles probably would look more like Dark Star thermostellar bombs, and pack nicer too.

So, feel free to have that IYTU. Either way, it's a look and feel choice.

I wasn't aware the OP's initial post places a strait jacket on related subject matter. I'll take that under advisement, but likely will not follow that ethos.

I am well aware of the SS3 parameters, I would think several threads getting into all that would have made that clear.

I don't see what argument you think you are winning here, as we all know current tech doesn't do this in any way shape or form, including the OP.

Then, it's a matter of aesthetic choice how far we go with the rules as presented vs. what we ref as explanations for those rules, or changes to performance parameters more in line with our vision.

 

[Hal]

I'm wondering why the JTAS special missile supplement hasn't been mentioned as yet...