GT ISW Ship Design System [FAQ and Problems]

[nik1979]

Trying to fill in the gaps of ISW, GT3e and UT4e.

How i calculated the damage:
[Dice x 3.5 (dice average) x 10 (from deca scale) ]^3 to get energy
from 250mm to 500mm magnitude factor of 3
Then ^1/3 the energy to get the damage, and divided it by 3.5 to get the dice.

HEMP 250mm missile $0.03M dDmg TL9-6dx2(10) cr inc, TL10-6dx2+12(10) cr inc; Range 3 maneuvers; Wt. 0.15T
HEMP 500mm missile $0.1M dDmg TL9-6dx3(10) cr inc, TL10-6dx3+18(10) cr inc.; Range 5 maneuvers; Wt. 0.5T

Fine Missiles, +1 Guidance roll, x2 Cost
Very Fine Missiles, +2 Guidance roll, x5 Cost

Nuclear Missiles UT156
Cost x1,000
Nuke 250mm (10 Kilo-Ton) $30M dDmg 6dx400 cr (8400 dmg)
Nuke 500mm (1 Mega-Ton) $100M dDmg 6dx2000 cr (42,000 dmg)
Special note of Nuclear Missiles: It usually does proximity kills, allowing them to overcome repulsors.

One can Simplify it by giving it a Proximity damage progression of the sort. Like: +5 to ram, dDmg 6dx30 250mm or 6dx50 for 500mm

X-Ray Laser Heads: basically a missile that can attack a number of hexes away.
Cost x10
X-Ray Laser Heads 250mm Gunnery-15+2Acc, dDmg 4d(5) burn, ROF20, range 2/6
X-Ray Laser Heads 500mm Gunnery-15+2Acc, dDmg 7d(5) burn, ROF20, range 2/6

Originally Posted by How to make Nukes Work

This attack assumes the missile wasn't stopped outside the ships hex. Until I figure out a simpler system this is the math I can think off that would make sense of the use of Nukes (because their minimum damage will wipe out any ship).

Glossary of Variables:
Proximity Attack Value (ProxA). This is the range a missile needs to detonate to deal enough damage to the defender that would matter. This is a ramming bonus for the missile.
Attack Superiority (AS). this determines how much damage the ship may take relative to how successful his defense is.
Penetration Value (Pen) - this is penetration bonus an attack has to overwhelm defenses. Usually Equal to the no. Of penetration aids, missile attacks, and
Point Defense Value (PD) - this is the Point Defense strength of the defender. Usually equal to the no. of point defense guns and screening elements x defender's point defense gunnery margin of success.
Nuclear Damage


First, Get the Attack Superiority (AS). This is equal to the Penetration (Pen) divided by Point Defense (PD) Value. Pen/PD = AS.

Second, Get the Proximity Attack Value (ProxA). This is equal to the Nuclear Attack Average dDmg divided by AS/DS x HP and DR.

Nuke dDmg/ [ (dHP*DS) + dDR] = ProxA

Look up the ProxA under the size table, that value will be the bonus of the Nuke to get close enough to the area of the ship.

Last, resolve Damage. Damage is equal to the Ship's dHP x AS. Of course the lower the attack superiority the better the chances the ship can survive a nuclear attack.

Example:
In a squadron engagement, the Vilani Fleet launches a light nuke along with penetration aids equal to x20 (EW missiles along with the nuke to confuse point defense targeting and acquisition).

The Terran Fleet's are bracing for the attack, allocating half the squadrons point defense ability 30. The Terrans make a margin of 3 with the Point Defense. The defense Reducing the Attack Superiority to 0.22.

The Missile just needs to within 50m to deal 154dDmg (or 15dDmg past the armor). This gives the missile a +8 bonus because of the proximity size to ramm the ship. Failure means no damage at all or the ship takes the damage.

EW Drone 500mm $0.16M, Accel 6, Mass 0.5Tons,
Drones causes all Targeting and Scanning Electronics that pass by their affected area (1 hex) to Make a "Save" or lose acquisition (roll the missile's guidance system skill, which is typically 15). The Save Penalty is equal to Drone's EW rating (-3 at TL9, -4 at TL10). Cost x2 for a Fine EW Drone (improve the drones effectiveness by 1), Cost x5 for a Very Fine EW Drone (improve the drone's effectiveness by 2). $0.16M each.

[Mgellis]

Originally Posted by nik1979

Trying to fill in the gaps of ISW, GT3e and UT4e.

How i calculated the damage:
[Dice x 3.5 (dice average) x 10 (from deca scale) ]^3 to get energy
from 250mm to 500mm magnitude factor of 3
Then ^1/3 the energy to get the damage, and divided it by 3.5 to get the dice.

HEMP 250mm missile $0.03M dDmg TL9-6dx2(10) cr inc, TL10-6dx2+12(10) cr inc; Range 3 maneuvers; Wt. 0.15T
HEMP 500mm missile $0.1M dDmg TL9-6dx3(10) cr inc, TL10-6dx3+18(10) cr inc.; Range 5 maneuvers; Wt. 0.5T

Fine Missiles, +1 Guidance roll, x2 Cost
Very Fine Missiles, +2 Guidance roll, x5 Cost

Nuclear Missiles UT156
Cost x1,000
Nuke 250mm (10 Kilo-Ton) $30M dDmg 6dx400 cr (8400 dmg)
Nuke 500mm (1 Mega-Ton) $100M dDmg 6dx2000 cr (42,000 dmg)
Special note of Nuclear Missiles: It usually does proximity kills, allowing them to overcome repulsors.


X-Ray Laser Heads: basically a missile that can attack a number of hexes away.
Cost x10
X-Ray Laser Heads 250mm Gunnery-15+2Acc, dDmg 4d(5) burn, ROF20, range 2/6
X-Ray Laser Heads 500mm Gunnery-15+2Acc, dDmg 7d(5) burn, ROF20, range 2/6



EW Drone 500mm $0.16M, Accel 6, Mass 0.5Tons,
Drones causes all Targeting and Scanning Electronics that pass by their affected area (1 hex) to Make a "Save" or lose acquisition (roll the missile's guidance system skill, which is typically 15). The Save Penalty is equal to Drone's EW rating (-3 at TL9, -4 at TL10). Cost x2 for a Fine EW Drone (improve the drones effectiveness by 1), Cost x5 for a Very Fine EW Drone (improve the drone's effectiveness by 2). $0.16M each.

I actually put the standard missile at 200 mm. (See the article I just published in JTAS.) The reason is that, if you're using the ship design system in GT:IW, the damage is 12d(10) when using the d-damage scale, or 6d x 20 (10) in the normal damage scale. This is twice the damage of the 100 mm. TL 9 HEAT round from Ultra-Tech, which suggests the missile is 200 mm. since damage seems to scale directly with warhead diameter.

It's also a lot easier to scale up the warheads since there is a 100 mm. warhead in Ultra-Tech. 8 x mass and cost of a 100 mm. warhead for a 200 mm. warhead, and effects are either x2 or x2.8, depending on the type of warhead.

If you look at missile weights in Spaceships, a 200 mm. missile is 250 lbs. and a 240 mm. warhead is 500 lbs., so 200 mm. is a better match for the .15 tons of the standard missile on that scale, too.

Suffice that, for a 4e GURPS Traveller campaign, I've made the argument that the missiles are 200 mm. And Loren seemed happy to publish it that way.

Interestingly, the missiles in Traveller are quite small, considering they're anti-ship weapons. I guess the idea is that you fire a lot of them, since lasers will probably get most of them, but it's like battleships fighting with AMRAAMs instead of Harpoons. :)

Mark

[nik1979]

Thanks Mark,
hehehe, your making it hard to ignore that subscription. I've placed my order at e23 now.
Any plans of making Mass Combat Stats for Traveller Ships?

The change from 200mm actually doesn't change my calculations that much. After accumulating all this data and having a naval doctrine down pat, I'm surprised there was no CCG designed after that. Once you have the established doctrines and technological paths set, you can pretty much design an Abstract fleet action and naval Strategy Card Game by it.

The CCG could possibly accommodate both fleet doctrines of Lost Fleet and Honorverse.

Asset Cards for Ships, Captains, Elite Fighter Squadrons, Bases, Shipyards, and Locations.
Action Cards for Special Fleet Maneuvers (Which need certain requirements), EW or ECM actions and drones, special attacks, traps, mines/pods, ambushes, random chance, etc.
Faction Cards. Grants a special advantage to the player. Like bonuses over generic ship stats (the difference between faction Y and W EW, Accel, Attack Range, or special maneuvers)
and with 3d6 resolutions for some elements (target number resolution so that its upward progression).

I'm trying to build some default ship stats based on ISW's

BTW, I've noticed ramming is not that hard given the factors of ship size and proximity explosions.
Ramming a ship like the Indomitable with size +13 offsets much of the +15 contested skill advantage.
If screening ships are able to pin point an enemy ship (augmenting the effective detection range of the launching ship to almost double): Scan-16(model-0) + Scan-24(model-9) can allow a missile to travel an 8 (w/c requires 9 rounds to max out accel) space vector towards a targeted ship.
I've begging to notice the usefulness of "ships of the wall". Basically dreadnaughts with a 6 point defense laser slots per heavy turret or up to about 396 point defense slots.


This means that Point Defense (PD) will be occurring at the ship's hex as part of the PD phase. Screening ships, will have a -4 (at the safest range of 12, or less at 2), +2 (accell), +13 (size) vs the repulsor-ed ship of +15 and other bonuses depending on the Penetration Aids for the Missiles or the EW/ECM abilities of the warship.

High Explosive Proximity Kill Missiles like Nukes, makes the job easier for the missiles.

[Mgellis]

Originally Posted by nik1979

Thanks Mark,
hehehe, your making it hard to ignore that subscription. I've placed my order at e23 now.
Any plans of making Mass Combat Stats for Traveller Ships?

The change from 200mm actually doesn't change my calculations that much. After accumulating all this data and having a naval doctrine down pat, I'm surprised there was no CCG designed after that. Once you have the established doctrines and technological paths set, you can pretty much design an Abstract fleet action and naval Strategy Card Game by it.

The CCG could possibly accommodate both fleet doctrines of Lost Fleet and Honorverse.

Asset Cards for Ships, Captains, Elite Fighter Squadrons, Bases, Shipyards, and Locations.
Action Cards for Special Fleet Maneuvers (Which need certain requirements), EW or ECM actions and drones, special attacks, traps, mines/pods, ambushes, random chance, etc.
Faction Cards. Grants a special advantage to the player. Like bonuses over generic ship stats (the difference between faction Y and W EW, Accel, Attack Range, or special maneuvers)
and with 3d6 resolutions for some elements (target number resolution so that its upward progression).

I'm trying to build some default ship stats based on ISW's

BTW, I've noticed ramming is not that hard given the factors of ship size and proximity explosions.
Ramming a ship like the Indomitable with size +13 offsets much of the +15 contested skill advantage.
If screening ships are able to pin point an enemy ship (augmenting the effective detection range of the launching ship to almost double): Scan-16(model-0) + Scan-24(model-9) can allow a missile to travel an 8 (w/c requires 9 rounds to max out accel) space vector towards a targeted ship.
I've begging to notice the usefulness of "ships of the wall". Basically dreadnaughts with a 6 point defense laser slots per heavy turret or up to about 396 point defense slots.


This means that Point Defense (PD) will be occurring at the ship's hex as part of the PD phase. Screening ships, will have a -4 (at the safest range of 12, or less at 2), +2 (accell), +13 (size) vs the repulsor-ed ship of +15 and other bonuses depending on the Penetration Aids for the Missiles or the EW/ECM abilities of the warship.

High Explosive Proximity Kill Missiles like Nukes, makes the job easier for the missiles.

I think you will enjoy JTAS. At $20, it's a great deal. Even if you don't like some of the articles, I'm sure you will get $20 worth and more over two years.

I have Mass Combat and it looks interesting, but I haven't played around with it too much. Right now, I'm finishing up some JTAS articles and playing around with ideas for new ones. I've got a few "Ships of the Third Imperium" article ideas that I'll probably flesh out in the next few months. More in my master plan to publish a GURPS Traveller: Third Imperium for 4e GURPS book as a large series of JTAS articles. :)

The 3e GT missiles were actually 250 mm. and 500 mm., but when I compared them to warheads in 4e Ultra-Tech, etc., 200 mm. made more sense. And it is easier to figure things out.

I've tried very hard to stay close to canon, but I also think that modifying Traveller for 4e GURPS is a great opportunity to streamline things, reinvent things that were clunky or odd, etc.

I'm not really that into CCGs, but I like your ideas. There might be licensing issues with Traveller, but maybe SJG will develop a Spaceships CCG.

As far as ramming goes...I'm not sure the Third Imperium would do this, but I wouldn't be surprised if some space navies relied on robot fighters as "I don't care how much armor you have" missiles. :) No warhead, just a cockpit, a computer with NAI software, some sensors, and lots of maneuver drive. Crank that baby up to maximum speed and kamikaze in. A hundred of those things would cost a pretty penny, but they would probably overwhelm a dreadnought's defenses and a dreadnought costs a lot more, so the guys with the big robot missiles win. :)

I think nukes (clean fusion weapons that can't be turned off by dampers) would serve as the "equalizer" in naval combat and makes the game more interesting. Dreadnoughts will usually beat little ships, even those armed with nukes, but at the little ships will have a chance. And that makes it interesting.

Mark

[nik1979]

Considering to Bridge UT, HT and ISW

Couldn't ship costs follow the UT/HT x2 cost options? The escalating cost of +2 HT for x4 is a too big. Considering warship or frontier merchants who are required to operating far from possible proper support services, costs of X4 for a +2 HT seems to me inconsistent. Considering the huge cost jump, couldn't there be better examples of why it is such a valuable advantage that it justifies x4 cost? Because if its not that justifiable and from how I've noticed how my group looks at it then that rule should be reconisidered.

In my examination and tinkering, the Cheap Option in UT/HT is much better. Since Cheap can increase the mass, it will make a ship certainly slower. Example: Cheap Hero Class will have an Accel of 1.2 vs 1.5. Since Cheap also has the fragile option (-2 HT) the option for reliable trade off for price is still available.

Separating the x2 cost categories to Rugged and Expensive is also viable. The Rugged modifier will slow a ship down (+20% mass; Ex. Rugged Hero Class Accel 1.4), probably not doubling the DR (or just giving a +10% DR instead), increasing the HT by 2. Mixing Rugged but Cheap (heavy and not the fragile) option creates a can have x1.8 Mass and makes for a slow but affordable Frontier Operating Ship (Hero Class at Accel 1.2).

The expensive option, which really isn't that ideal for ships that are supposed to work in rugged conditions, would be great with a yacht (Accel 2.0 to 2.5), interplanetary shuttle (accel 1.3 to 1.5).

On Accel, isnt a difference between two accel, ex. Accel 1 and 6, merit a bonus far greater than half the difference? In the duration of a combat round, i just find the bonus disproportionate to my experience in flight simulations and how TDMs are scaled.

Are there inertia dampers in ships? Because, I'm wondering at the description of repulsors and how much they are related to inertia dampers.