Steve Jackson Games Forums

Steve Jackson Games Forums (https://forums.sjgames.com/index.php)
-   GURPS (https://forums.sjgames.com/forumdisplay.php?f=13)
-   -   [Spaceships] Calculating Missile Damage (https://forums.sjgames.com/showthread.php?t=73995)

panton41 10-20-2010 08:43 PM

[Spaceships] Calculating Missile Damage
 
I'm working on a space fighter game and I'm needing a rules clarification on missiles.

Despite reading the rules I'm a bit unclear on how missile damage is calculated. Are the attacker and defender's relative velocity added to the damage the missile does and if so what does that mean in a situation like a Fast Pass or between vehicles with vastly different accelerations?

Oh, and to make the question that much more complex does the same rule apply to both Basic and Tactical rules?

Fred Brackin 10-20-2010 08:48 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by ciaran_skye (Post 1066030)
Are the attacker and defender's relative velocity added to the damage the missile does and if so what does that mean in a situation like a Fast Pass or between vehicles with vastly different accelerations?

Yep. Fast Passes are killers and the more velocity that is involved, the more damage results. I say it's at least as bad as you think it might be.

Diomedes 10-20-2010 08:52 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by ciaran_skye (Post 1066030)
I'm working on a space fighter game and I'm needing a rules clarification on missiles.

Despite reading the rules I'm a bit unclear on how missile damage is calculated. Are the attacker and defender's relative velocity added to the damage the missile does and if so what does that mean in a situation like a Fast Pass or between vehicles with vastly different accelerations?

Oh, and to make the question that much more complex does the same rule apply to both Basic and Tactical rules?

In Basic combat, you multiply the weapon damage for the appropriate caliber by the relative velocity from the table on page SS59. For a fast pass, you use the actual relative velocity instead (which is likely to be much bigger).

In Tactical combat, you multiply the basic damage by the relative velocity in hexes per turn (calculated on page SS3:31), and by the scale factor from page SS3:32.

panton41 10-20-2010 09:18 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by Fred Brackin (Post 1066033)
Yep. Fast Passes are killers and the more velocity that is involved, the more damage results. I say it's at least as bad as you think it might be.

So, in the case of the game I'm planning, might this allow fighters to crack large capital ships without nukes? It's late and I'm too lazy/tired to bring up the PDFs and do the math. For what it's worth, I'm planning on allowing the whole genre convention of fighters being significantly faster than capital ships.

Diomedes 10-20-2010 09:25 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by ciaran_skye (Post 1066044)
So, in the case of the game I'm planning, might this allow fighters to crack large capital ships without nukes? It's late and I'm too lazy/tired to bring up the PDFs and do the math. For what it's worth, I'm planning on allowing the whole genre convention of fighters being significantly faster than capital ships.

Nukes don't take any modifications for relative velocity, since they have to detonate before they collide with the hull, or they won't go off at all.

That said, they're quite powerful enough on their own to ruin even a large warship's day.

vierasmarius 10-20-2010 09:30 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by ciaran_skye (Post 1066044)
So, in the case of the game I'm planning, might this allow fighters to crack large capital ships without nukes? It's late and I'm too lazy/tired to bring up the PDFs and do the math. For what it's worth, I'm planning on allowing the whole genre convention of fighters being significantly faster than capital ships.

Easily. Even without using Fast Passes, just the "default" relative velocity of 5mps for TL 7-8 missiles, a 20cm Missile (fired by a SM +5 Major Battery) can easily inflict 6dx25(2). An average of 525 damage, this will drop a SM +12 ship to 0 HP through DR 400. A SM +8 ship would almost certainly be destroyed instantly. If you add in higher relative velocities the devastation will be proportionally greater.

EDIT: Oh, just noticed that the errata not only corrected base projectile damage, but also default relative velocity. So a TL9 20cm missile would typically do on 6d10(2). That's still enough to disable a SM +12 ship, but only with DR 100. The max DR it could crack is about 700. But again, that's without making a Fast Pass.

panton41 10-20-2010 09:31 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by Diomedes (Post 1066047)
Nukes don't take any modifications for relative velocity, since they have to detonate before they collide with the hull, or they won't go off at all.

That said, they're quite powerful enough on their own to ruin even a large warship's day.

I was basing it on using nukes instead of kinetic kill. I knew that nukes didn't take the adjustment, just that their high damage would be enough for a fighter's nuclear missiles to kill a capital ship. What I was asking was whether in a fast pass could the kinetic kill weapons do enough damage to penetrate a capital ships armor or would nuclear weapons be the only way to achieve that with a small ship?


Quote:

Originally Posted by vierasmarius (Post 1066048)
Easily. Even without using Fast Passes, just the "default" relative velocity of 5mps for TL 7-8 missiles, a 20cm Missile (fired by a SM +5 Major Battery) can easily inflict 6dx25(2). An average of 525 damage, this will drop a SM +12 ship to 0 HP through DR 400. A SM +8 ship would almost certainly be destroyed instantly. If you add in higher relative velocities the devastation will be proportionally greater.

Ninja'd, though I think that 5mps is an errata that's been changed to 1-2mps. So a tactic for my fighter pilot characters might be to use their "guns" against other fighters and what would amount to "chinks in armor" in bigger ships and use missiles vs. capital ships.

Ulzgoroth 10-20-2010 09:40 PM

Re: [Spaceships] Calculating Missile Damage
 
If your fighters have enough delta-V and acceleration, they can easily crack capital ships with missiles. The only major limitation is how high a relative speed they can get the missiles to actually hit at. Potentially they could even use bombs (SS4).
Quote:

Originally Posted by ciaran_skye (Post 1066049)
Ninja'd, though I think that 5mps is an errata that's been changed to 1mps. So a tactic for my fighter pilot characters might be to use their "guns" against other fighters and what would amount to "chinks in armor" in bigger ships and use missiles vs. capital ships.

Hopefully these guns are beams? Because actual guns are even more useless in fast pass regimes than otherwise.

vierasmarius 10-20-2010 09:43 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by ciaran_skye (Post 1066049)
Ninja'd, though I think that 5mps is an errata that's been changed to 1-2mps.

Yeah, I just noticed that. Oops.

Quote:

At this rate Low Tech will also cure cancer, settle the American healthcare debate and if you buy a copy Jesus will give you a kitten.
I'm still waiting for my kitten!

Fred Brackin 10-20-2010 09:56 PM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by ciaran_skye (Post 1066044)
So, in the case of the game I'm planning, might this allow fighters to crack large capital ships without nukes?

During the Tactical combat playtest I had the Free Libertarians of the Outer Solar System stage a Fast Pass sort of raid on the Greater League of United Earth.

Some Nova class carriers accelerated all the way towards Earth from Mars and released their load of kamikaze TL8 ASATs at about 70 miles per second One of the ASAT's sub-munitions did enough to autokill a SM+14 Gibralter class battlestation (with some leftover too).

So, yes you can kill big ships with little missiles if you have enough velocity.

It's not an unstoppable tactic but it's a sufficiently powerful one that you're going to have to pay major attention to preventing high speed kinetic energy attacks on your major space assets.

panton41 10-21-2010 02:35 AM

Re: [Spaceships] Calculating Missile Damage
 
Quote:

Originally Posted by vierasmarius (Post 1066054)
I'm still waiting for my kitten!

I've been meaning to get a picture of my kitten and Low Tech on my Kindle in the same shot.


All times are GMT -6. The time now is 05:49 PM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.