Starship weapons questions

[JAFARR]

In the thread listed below,
http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=18669
comments were made to the effect that using ship's weapons in close proximity to another ship or even the hold of a larger ship would not do damage to the firing ship. It seems to me that I remember something about burst radius of missiles and energy weapons. I have searched everything on the CT CDROM and got no results. This includes Bk2, HG, Starter Traveller, The Traveller Book and even includes looking up plasma & fusion weapons in Mercenary. Does anyone know anything about this subject from MT or the Starship Operations Manual. The other possibility
is this came from a former referee/GM. Any comments?

I will be looking in MT in the mean time.

 

[Hal]

Hi Andy,
Rather than read the entire thread you alluded to in your first post, can you be more specific in your question relative to the pertinent thread. A specific post number or something to that effect?

Ultimately, you have to decide as a GM, what the precise situation is regarding the circumstances portrayed in the game with you (presumably) the GM making decisions.

For instance? A ship being held inside the hold of another ship - with the first ship's lasers being used to fire on the inner cargo bay's hold bulkheads is probably not going to be a good thing to deal with. Why? In real life, you have a weapon designed to pump a LOT of energy into a very small area. How big or small of an area will depend in part, on you doing the research into the rules as written. Striker for example, indicates that there is a very specific diameter of a laser beam weapon. If you go with that route, you'll suspect that the shipboard laser of the ship in the cargo bay, is going to punch a very definite hole into the bulkheads, and cause the remaining metal surrounding the hole to heat up very rapidly, perhaps buckle from the heat, and probably radiate heat away from the impact location. If that laser is firing multiple shots in a 20 minute period of time (High Guard) or within a 1000 second period of time (CT), then you may need to determine just how often the ship's laser is going to be able to fire.

Likewise, I don't recall if Striker had rules for how much warhead filler a given missile contains. I know that were I a ship owner buying a missile system for my ship, I'd want a safe arming distance from the time the missile is launched before it becomes armed and ready to explode. I'd be awfully unhappy if a missile exploded in the missile launch rack inside of a turret - if you know what I mean. Sandcasters if I recall correctly, were to be treated like a giant shotgun system, which means that it can be utilized as an anti-personnel weapon to some extent. Problem is? If a person is at ground zero where 10,000 ball bearings go off, they're going to be shredded. Likewise, the question becomes one of "how much damage can a sandcaster inflict on any one person at any given point?"

Your best bet would be to design actual Striker weapon analogs of the ship's weapons, find out where the reference is that sandcasters are like big overwhelming shotguns, etc - and then see how it fits within your own game world universe. Part of the problem lies with the fact that there are no iron clad rules (that I'm aware of, but I'm not an expert at this either!) that tells you how much damage a ship's structural rib can take before it buckles, or how much damage is required to penetrate 4 inches of Durasteel bulkheads, or what have you.

My gut level instinct is that you seem to want Striker like rules for use inside of a starship overall. So - read the rules outright and see what it helps you to handle.

Hal

 

[Icosahedron]

As Hal suggests, Striker contains details of burst radii for energy weapons and missile warheads.

IIRC from that thread, my suggestion wasn't that no damage would be done to the firing ship, but that the damage sustained by the firing ship, thanks to the protection of its hull armour, would be very much less than that sustained by the larger ship and therefore the risk might be worth taking - especially if the small ship captain figured the situation was desperate. Exactly how much damage might be inflicted by 'riccochets' is a matter for the referee.

 

[samuelvss]

Striker does have such tables, but the gist is as follows: lasers have no burst radii and the rest do. This is for the effects on personnel, who may be unprotected or wearing up to 18 (20?) level armor; a starship's hull starts at 40, so only nukes or really huge energy weapons get up to that level of penetration (IIRC). I would say the practical effect on the firer of starship weapons turret fired at a target in close proximity (say 20 to 50 meters) of the firer would be none.

Missiles will have arming sequences built in, and thus be unusable. Fusion and plasma weapons will splatter bystanders in vaccsuits a wee bit, and chip your paint. Lasers will have no effects on the firer.

 

[atpollard]

Striker does have such tables, but the gist is as follows: lasers have no burst radii and the rest do.

Fusion and plasma weapons will splatter bystanders in vaccsuits a wee bit, and chip your paint. Lasers will have no effects on the firer.

I suspect that while this may be a correct interpretation of the rules, in the realm of real world physics, energy is energy. A bomb, a jet of plasma, and a beam of coherent photons all powerful enough to destroy 14 cubic meters of 40 cm armor, would be equally harmful to any one or thing in the vicinity.

 

[JAFARR]

Hi Andy,
Rather than read the entire thread you alluded to in your first post, can you be more specific in your question relative to the pertinent thread. A specific post number or something to that effect?

...
Hal

Basically the last 2 pages. In a nut shell I proposed a 5ktn freighter with a capture bay able to hold 1500 tons of other ships. Someone said that if his ship's weapons were not destroyed in the battle prior to being placed in the capture bay, that he would then attack the larger ship from inside. My thought would be that you would do as much damage to your own ship as to the other one.
Samuelvss' statement about missiles and arming sequences making missiles useless in this instance makes sense, similar to modern day sub's torpedoes requiring a minimum run distance to arm for self protection. Also the part about lasers having no burst radius, however the Q ship is also equipped with a fusion gun turret which would IMO have a burst radius.

Maybe the best approach to the whole thing would be to to make a blanket statement before play ever begins to the effect that there things that the rules just don't cover and as it's MTU, that in those cases I will make rulings/suggestions as to the way I think things will work, with the caveat that other referees may rule differently. Especially as I am targeting this at new (to Traveller) players.

 

[tbeard1999]

Basically the last 2 pages. In a nut shell I proposed a 5ktn freighter with a capture bay able to hold 1500 tons of other ships. Someone said that if his ship's weapons were not destroyed in the battle prior to being placed in the capture bay, that he would then attack the larger ship from inside. My thought would be that you would do as much damage to your own ship as to the other one.

I don't think that's necessarily correct. A laser, in particular wouldn't cause blowback sufficient to imperil the firing ship. And given that the interior walls of a ship are far weaker than the hull (especially an armored hull), a laser shot from within could probably do a shocking amount of damage. Aim it in the general direction of the drives and cut loose.

EDIT: Explosives would either be shaped charge (in which the explosive force would be focused in the direction leading away from the firing ship) or contact HE (which would cause FAR more damage to the larger ship than to the firing ship). Note that shrapnel would have little effect on Traveller starships -- even unarmored ships have the equivalent of 1.9 meters of steel armor. (Per Striker).

As an aside, Striker's ratings for starship hulls is absurdly high, given its ratings for missiles. Striker says that unarmored starships have an armor value of 60 (equivalent to 1.9 meters of steel armor). But Starship missiles have 15cm warheads, which even at TL15 yield a penetration of ~95cm (for shaped charge HEAP warheads) or ~19cm for high explosive warheads. IMTU, starship hulls are far thinner -- about 10cm or so.

In any case, Star Wars notwithstanding, it seems wildly foolish to allow an armed ship within your hull. (Never thought of that before...) I suspect that small craft would be a far better solution for boarding parties. The mother ship could stand off and cover them as they come in. (In most cases, I'd think a boarding party would be sent in after the enemy ship has surrendered).

I guess you could assume that the docking bay is unarmored and that its interior walls *are* armored, which would make such a tactic far less effective. Unfortunately, such a bay would be very vulnerable to destruction in combat.

 

[samuelvss]

.....in the realm of real world physics, energy is energy. A bomb, a jet of plasma, and a beam of coherent photons all powerful enough to destroy 14 cubic meters of 40 cm armor, would be equally harmful to any one or thing in the vicinity.

I'm not sure where you get the 1 dton of hull; Striker specifically deals with penetration. The penetration needed to get through 40 cm of armor and to destroy 1 dton of armor are different by orders of magnitude.

That aside, though, you make another point: Energy is energy, in some respects, but not all, and especially not in terminal ballstics. Lasers penetrate, while fusion and plasma guns penetrate and explode; a useful ananlogy is a sabot round (APFSDS) [KEAP, I believe, in Striker] and a shaped charge (HEAT) as they might impact the glacis of a tank. Both penetrate, but the sabot does so with no explosion on the surface of the target. One a couple meters (to the sides or in the direction from which the round came) in shirt sleeves would be in no harm. One a couple meters away (same directions) from a 120mm HEAT round (not ideal for use against a tank's frontal arc, anyway, but usefule for this anaology) would get pretty rocked, fragged, and perforated. In both cases, a great deal of energey is expended. In either case, a couple of inches of aluminum armor, not sufficient to stop any penetration larger than .30 cal (7.62mm), would keep you snug as a bug (to the sides or in the direction from which the round came).

Directed energy is directed, and will take quite a bit to RE-direct. Lasers don't, from anything anywhere in canon, just blow up on the surface: they penetrate. Those on the far side of the bulkhead need to worry.

 

[aramis]

It should be noted that MT (which uses the same scale for armor and pen as Striker) reduces standard hulls to 40, and there was errata on a sheet from GDW doing the same on a friend's striker box...

 

[tbeard1999]

It should be noted that MT (which uses the same scale for armor and pen as Striker) reduces standard hulls to 40, and there was errata on a sheet from GDW doing the same on a friend's striker box...

Ah, you're correct. I'd forgotten about the eratta. However, I think that this is still way too high (if you accept Striker's rating for starship missiles) at 33.6cm of armor (equivalent to a 1970-1980s era main battle tank). 15cm HE missiles would still be unable to penetrate that armor, although 15cm HEAP missiles would be able to do so easily.

By the way, the starship missile roughly corresponds in size to the AGM-114 Hellfire, a TL8 target designated (laser guided semi active homing) tac missile with a battlefield range of 8km. Late TL8 models incorporate target memory (aka "Fire and Forget") guidance.

 

[Hal]

Ah, you're correct. I'd forgotten about the eratta. However, I think that this is still way too high (if you accept Striker's rating for starship missiles) at 33.6cm of armor (equivalent to a 1970-1980s era main battle tank). 15cm HE missiles would still be unable to penetrate that armor, although 15cm HEAP missiles would be able to do so easily.

By the way, the starship missile roughly corresponds in size to the AGM-114 Hellfire, a TL8 target designated (laser guided semi active homing) tac missile with a battlefield range of 8km. Late TL8 models incorporate target memory (aka "Fire and Forget") guidance.

One thing to keep at the forefront of your mind is that if any sci-fi game system starts off with a vehicle design system from the get-go, and then builds upon that foundation, such a game universe will have internal self-consistency. However, when a game world starts off, and things are added by the rule of thumb concept, and subsequent to that, a game design system is implemented - you will find that there are going to be inconsistencies between the two "design philosophies". David Pulver discovered this when he created a unified vehicle design system and checked the designed items against those introduced by basically, fiat, in earlier game systems. You can't quite make the rule of thumb items match the designed items, and vice versa.

That having been said? There is nothing to keep people from tossing older earlier items from Traveller and using only Striker produced items

 

[tbeard1999]

One thing to keep at the forefront of your mind is that if any sci-fi game system starts off with a vehicle design system from the get-go, and then builds upon that foundation, such a game universe will have internal self-consistency. However, when a game world starts off, and things are added by the rule of thumb concept, and subsequent to that, a game design system is implemented - you will find that there are going to be inconsistencies between the two "design philosophies". David Pulver discovered this when he created a unified vehicle design system and checked the designed items against those introduced by basically, fiat, in earlier game systems. You can't quite make the rule of thumb items match the designed items, and vice versa.

Yeah, I realize that, but I think that the problem here is that the designers of Striker didn't bother to actually check the performance of the High Guard equivalent weapons. In any case, the problem is easy to fix -- just lower the assumed hull armor for unarmored starships.

And universal/unified design systems are often (IMHO) not worth the trouble. They're often incredibly fiddly and often fail to accurately replicate Real World gear. I enjoy design systems like HG, Book 2 and Car Wars. Beyond that, I get bored quick.

 

[aramis]

I think integrated design systems are fine, provided they have staged granularity.

EG:

small Vehicles to the 100L chunk
Large vehicles, KL
Small Craft to the 0.1 Dton (1.4KL, on par with vehicles)
Small shipping to the DTon or half Dton
Large craft (1000Dton+) to the 10Dton,
and huge craft (10KDton) to the 100DTon.​

But that being said, the thing I love most about MT is the integration of damage systems across the scale (ignoring, for the moment, MT HG in the MT RM)... I can adjudicate fairly small arms against big ships, and big ships, with danger spaces of 15-50m, against people and groups

 

[samuelvss]

15cm HE missiles would still be unable to penetrate that armor, although 15cm HEAP missiles would be able to do so easily.

You'd never use HE to punch through armor, though.

Anti-ship missiles would be HEAP, with HE a specialty for planetary bombardment. And anyone who could would use nukes, ala HBP's "blow them Emcee Squared."

Whence this thread began, however: missiles inside a bay would be right out! Lasers would have no effect on the firing ship, nor would fusion or plasma guns. Per Striker, canon, any other rule I can think of, and MHO.

 

[Mithras]

For my own game reference, does anyone have any idea what modern weapon systems might compare to the destructive power of beam, pulse lasers, HE and nuclear missiles in Classic?

Just how big/powerful are these missiles? Harpoons? Tomahawks? Shrikes?

I have no idea, but it would help when building my own.

 

[samuelvss]

Mithras: As tbeard posted in this thread, Striker lists the equivalent of a CT HE missile as the Hellfire.

Now to begin with, for this to be anything even remotely conceivable, we have to take HE to mean HEAP/HEAT: every ounce of that warhead has to be optimized for punching through that starship's hull.

There has been some general discord [in this very thread!] as to usefulness of these CT equivalents of Striker's. Personally, with the errata hull value of 40, I am O.K. with all except the missiles. I think there's only so much technology can eek out of a 9 k.g. warhead. Then again, a harpoon's prolly a bit much.....:nonono:

 

[Mithras]

Grr sorry Samuel, that's what I get for skipping through the thread quickly.

 

[tbeard1999]

You'd never use HE to punch through armor, though.

Agreed, but nowhere is it stated that standard Traveller missiles are anything other than high explosive. And Special Supplement 3 refers to standard high explosive and "focused force" warheads, which are "developments of shaped charge warheads".

My main problem is that a shaped charge warhead the size of a Traveller missile would do very little damage to something as big as as starship, unless it struck a highly vulnerable point. It surely wouldn't do 3.5 times the damage as a beam laser (1d6 damage points in Book 2). So, in my mind, it pretty much *has* to be a high explosive warhead.

EDIT: actually, this may not be true. After thinking about it, a 50 kg missile flying for (say) 3 turns at 6G acceleration will do a tremendous amount of damage from kinetic energy. By that time, it will be going 27 km/second, which is 18 times the velocity of a modern hyper velocity tank gun. Even a proximity fused missile will do tremendous damage -- a high explosive fragmentation warhead with (say) 5 kg of fragments will do about 324 times as much damage as a 120mm TL hypervelocity tank round (~5 kg penetrator travelling at 1.5 km/sec). Even one turn at 6G acceleration will generate 36 times the energy of the tank round. So really, the HE charge is only necessary to spread the fragments out.

And I note that modern anti-ship missiles are in fact, not armor piercing. Like Book 2 starships, modern warships are not armored in any meaningful sense of the word.

Whence this thread began, however: missiles inside a bay would be right out!

Sorry, I don't agree. A standard missile would have about 3 kg of high explosive (per Striker). The blast radius for that would be 30-40m, but the main effect would be fragmentation, which would be stopped by any reasonable thickness of starship hull. The contact penetration would be ~18 cm, while the fragmentation penetration would be ~2 cm of steel armor.

And a shaped charge warhead missile would have very little fragmentation.

Lasers would have no effect on the firing ship, nor would fusion or plasma guns. Per Striker, canon, any other rule I can think of, and MHO.

Actually, given the "splatter" of plasma and fusion guns, they *might* cause some damage to the firing ship, especially if it was poorly armored. In Striker, a starship plasma gun has a burst radius of 237m. It will penetrate 174cm of steel armor -- easily enough to penetrate an unarmored starship hull, but not enough to penetrate HG armor 1+. A fusion gun has a burst radius of 330m cm. It will penetrate 494 cm of armor; enough to penetrate HG armor of 0-3.

Of course, these weapons would do an unspeakably horrible amount of damage to the enemy ship (plasma/fusion weapons do FAR more damage at point blank range like this).

I just think that it's stunningly foolish to allow an armed enemy ship into your docking bay...

 

[tbeard1999]

Real world performance of starship weapons (using Striker as the baseline):

	Rng	Penetration in cm
	(km)	TL8-12	TL13+
Beam			
  Eff	125	625	750
  Long	250	312.5	375
  Ext	1250	125	187.5
Pulse			
  Eff	166.6	833	999.6
  Long	333.2	416.5	499.8
  Ext	1666	166.6	250.5

Note: Eff = Effective Range; Long = Long Range (-2 to hit); Ext = Extreme Range (-4 to hit).

Plasma/Fusion Guns

	 Rng 	 Pen 	 Burst 	 Burst 
Plasma	 (km) 	 (cm) 	 (m) 	 (pen) 
  Eff	 16 	 7,500 	 237 	135
  Long	 32 	 2,500 	 158 	37
  Ext	 63 	 250 	 79 	18
Fusion				
  Eff	 34 	 20,000 	 335 	80
  Long	 67 	 7,500 	 224 	52
  Ext	 134 	 500 	 112 	26

Note: Burst(pen) is the penetration in cm of steel armor within the burst radius.

Missiles

	HEAP	HE	HE	HE
	Pen	Pen	Burst	Burst
TL	(cm)	(cm)	(m)	(pen)
8	52	 7.7 	30	1
9	62	 8.4 	30	1
10	62	 9.2 	30	1
11	67	 10.0 	40	1
12	67	 10.1 	40	1
13	73	 11.9 	40	1.25
14	73	 13.0 	40	1.25
15	73	 14.0 	40	1.25

Note: HE Burst(pen) is the penetration in cm of steel armor within the burst radius.

High Guard Armor

High Guard Armor	
Armor	 (cm)
0	 34 
1	 269 
2	 349 
3	 453 
4	 538 
5	 640 
6	 761 
7	 830 
8	 905 
9	 987 
10	 1,080 
11	 1,170 
12	 1,280 
13	 1,400 
14	 1,520 
15	 1,660 
	
High Guard Armor Adjusted
Armor	 (cm)
0	 34 
1	 48 
2	 62 
3	 80 
4	 95 
5	 113 
6	 135 
7	 147 
8	 160 
9	 174 
10	 190 
11	 207 
12	 226 
13	 247 
14	 269 
15	 293

"High Guard Armor Adjusted" is the armor ratings if you assume that the reduction of level 0 armor to Striker Armor 40 is also applied to the other armor levels.

Also note that on the ground, fire control systems would seriously limit the effective ranges of starship weapons:

Fire Control Range Limits (km)			
TL	Eff	Long	Ext
8	2	3	4.5
9	2.5	3.5	5
10	3	4	5.5
11	3.5	4.5	8
12	4.5	6	18
13	5.25	10.5	21
14	7.75	15.5	31
15	10	20	40

Note that Striker (and MegaTraveller) dramatically understates the armor piercing capability of TL 8+ HEAP and KEAP weapons; in the Real World, HEAP missiles would have 2-4 times the armor penetration.

Based on recent research for A Fistful of TOWs 3, a modern (TL8) main battle tank like the M1A2HA probably has frontal armor of about 80cm (180 cm vs HEAP and HE rounds). In the flank, the armor protection is probably 10-15 cm (40 cm vs HEAP and HE rounds). So a starship laser or fusion gun would make quick work out to maximum range. The M1A2HA main gun would have a real world penetration of about 110cm at 1200m range; 90cm at 2400m range; 70cm at 3600m range. So it could damage an unarmored starship.

Hope this helps.

 

[Hal]

tbeard's analsysis is one reason why I like Striker/VDS/GURPS VEHICLES type rules sets. Once you operate within a given framework, and you build weapons and/or vehicles per the rules, you can quickly ascertain how the weapons work together in the framework of the game world itself.

At one point in time, I wondered what future war might be like say, 50 years from now. I postulated a new type of weapon being phased in, a rail gun - along with the idea of individual battlesuits to augument troop efforts to fight on the ground. Then I wondered how effective a combined arms approach might be if each tank was assigned a squad/platoon of battle suits to work with it. In short, I dismantled the conventional approach of each tank being a squad, and 3 or 4 tanks being a platoon, etc. I started to work with an integrated combat system where the extra mobile sensors of the battle tank could be fed in as data to the main battle tank (named the M-10 Cohen). The main battle tank's gun could be fired at a target as far away as some 23 miles (if I recall correctly), allowing the Cohen tank to be fired either as a support weapon or as a direct fire weapon. Using the stats on a Destroyer, I determined that the Cohen itself could directly imperil or sink a Destroyer class ship.

The rail gun design was truly NASTY, and for the Cohen to even stand up to its own weapon on its frontal armor, the beast had to be extremely heavy. As it was, I tried very hard, using the Game system (GURPS VEHICLES for GURPS 3rd edition) to keep its stats within bounds of the M1A2 tank. Even then, I had to go a little higher and thought to myself "This beast can not traverse some of those bridges where its max load rated at 50 tons or less".

My main goal at that time, was to try out the concept of battle suits powered by gasoline or other sources, and see how they might dictate battle strategy or changes to the battlefront technology. There were some real eye openers in that for me The worst thing the tanks (and battlesuits) had to deal with, were issues involving anti-missile defenses. Missiles with sufficient warhead capabilities were cheap and high in number, while defenses against them were somewhat expensive.

But I digress. The M-10 Cohen tank I created, plus the battle suits that were supposed to act in concert with it - could damage a naval destroyer with the rail gun it carried. I suspect that tanks designed with striker, and starships designed with strike rules - would have suggest the same thing - that starships could be damaged by ground force tanks easily enough.