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-   -   [Spaceships] Missile shield vs. ramming: two questions (http://forums.sjgames.com/showthread.php?t=156970)

Michael Thayne 04-14-2018 06:15 PM

[Spaceships] Missile shield vs. ramming: two questions
 
I'm trying to figure out how to build a space combat paradigm where large warships make logical sense, as opposed to being the result of mindless aping of naval warfare. Not that we don't want to ape naval warfare, we just want to do so in a thoughtful way. Here "large" = SM+9 at a minimum, or ideally SM+10 or higher.

The basic problem here is that cost scales with volume, while damage, armor, and HP scale with length. The main thing that large warships have going for them is that (1) they can potentially have enough DR to be immune to beam attacks from smaller ships (2) they can have beam weapons powerful enough to penetrate such armor on enemy craft. Unfortunately, this logic doesn't apply so much to kinetic attacks, because kinetic attacks can do incredible amounts of damage, especially when using the tactical combat rules where you aren't arbitrarily limited to a scale-based velocity.

The missile shield design switch from Spaceships 3 seems essential here, to stop large warships from being missile bait. But what about ramming? A couple things are unclear to me. First, if your RoF is higher than the number of ramming ships, do you get one hit per ramming ship, or one hit per point of RoF, which can be divided freely among attacking ships? I can't quite tell from the wording of the rule ("Beam weapons that are assigned to point defense may therefore automatically hit a number of incoming ballistic weapons (or ramming spacecraft) up to their maximum rate of fire.")

Second, would it be reasonable to use the "missile shield" rules not just for beams but also missiles? It seems like this could be extremely helpful, because (1) dedicated suicide drones can have very heavy frontal armor, enough to bypass point-defense guns designed for unarmored missiles and (2) by the standard rules, a point-defense gunner has a minimum 5% miss chance. Point (2) means an SM+10 warship (weighing in at 10,000 tons) can easily be destroyed by a swarm of a dozen or so SM+4 drones (10 tons each).

Agemegos 04-14-2018 08:16 PM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Range.

You need a large objective to focus a beam at great distance, which in GURPS Spaceships means a powerful weapon, which requires a large ship. So build go with TL 10 or TL11 and build SM +12 warships with 100 GJ spinal UV or X-ray lasers. Fit each one out with a tertiary battery of thirty 1GJ very-rapid-fire UV lasers for RoF 3000 missile defence.

Then stand off at 100,000 miles and plink with the Big Gun. Any warhead or fire platform will cop hell while closing.

Michael Thayne 04-14-2018 08:37 PM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Agemegos (Post 2171248)
Range.

You need a large objective to focus a beam at great distance, which in GURPS Spaceships means a powerful weapon, which requires a large ship. So build go with TL 10 or TL11 and build SM +12 warships with 100 GJ spinal UV lasers. Fit each one out with a tertiary battery of thirty 1GJ very-rapid-fire UV lasers for RoF 3000 missile defence.

Then stand off at 100,000 miles and plink with the Big Gun. Any warhead or fire platform will cop hell while closing.

One issue here is that VRF beams have 1/100ths of the output of regular beams, so those won't be 1GJ VRF beams, they'll be 10 MJ VRF beams. So those guns won't be very useful against a well-armored drone. Devote most of your front hull to hardened nanocomposite, and it will be difficult to impossible to so much as scratch the drone.

As for the big gun, that can be overwhelmed by sheer numbers. The big gun might have a range of 50,000 miles. With TL10 or TL11 drives they can easily travel at speeds in excess of 25 MPS. At that speed, the big ship will have less than one hundred 20-second turns to destroy incoming drones. So 100+ drones will overwhelm the big gun. They'll add up to a mere 1% of the tonnage of the monster ship.

Look at the Nightgaunt dogfight drone in Spaceships 4 to see now this is done in detail. If you tone down the armament, you can give them a fifth front armor system for extra protection against the little guns.

Fred Brackin 04-14-2018 09:08 PM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Michael Thayne (Post 2171249)
One issue here is that VRF beams have 1/100ths of the output of regular beams, so those won't be 1GJ VRF beams, they'll be 10 MJ VRF beams. So those guns won't be very useful against a well-armored drone.

You can use Particle Beams in the tertiary battery for that (5) armor divisor. Keep the UV Laser in the main battery for the range though.

If you're really worried about those drones add a tertiary battery of missiles too. They'll kill drones easily.

Mostly I agree with Agamemos. Range kills in normal space/hard science combat.

Michael Thayne 04-14-2018 10:56 PM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Fred Brackin (Post 2171250)
If you're really worried about those drones add a tertiary battery of missiles too. They'll kill drones easily.

For an SM+12 ship, even if you use the Smaller Systems rules, the missiles will still cost $1M a pop, almost as much as a Nightgaunt drone. You're better off using a fighter screen.

More importantly, though, you still have a 5% miss chance with each shot by RAW. Hence why I asked if it would be reasonable to get rid of that minimum miss chance as a house rule.

Agemegos 04-15-2018 12:39 AM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Michael Thayne (Post 2171249)
Look at the Nightgaunt dogfight drone in Spaceships 8 to see now this is done in detail.

Can you give be a page reference on that, please? Acrobat Reader text search in my copy of Spaceships 8 doesn't show up "nightgaunt", "dogfight", or "drone".

Quote:

One issue here is that VRF beams have 1/100ths of the output of regular beams, so those won't be 1GJ VRF beams, they'll be 10 MJ VRF beams.
So they will. My mistake. What about using a secondary battery of rapid-fire improved lasers? Ten weapons each RoF 20, 300 MJ? Improved lasers are penetrating (2), but AKVs probably have hardened armour. 3 d-dice 5 should penetrate dDR 51, and damage an SM +6 AKV with five frontal systems of hardened nanocomposite. Range S/L, so you're getting effective damage out to 2,500 miles. A drone with 20 mps of delta=v is going to take at least 125 seconds to cross that, which is 6 20-second turns during which the defence gets 1,200 shots?

And if the thing that launches this salvo gets within 200,000 miles it can gloomily contemplate 100 GJ of x-rays: 2 d-dice 50 burn* sur (5), after which the ship gets to used the big gun for 500 twenty-second turns of defensive fire against KKVs with 20 mi/sec of delta-v.

Ulzgoroth 04-15-2018 12:59 AM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Agemegos (Post 2171274)
Can you give be a page reference on that, please? Acrobat Reader text search in my copy of Spaceships 8 doesn't show up "nightgaunt", "dogfight", or "drone".

It's on page 15...of Spaceships 4, not 8.

Agemegos 04-15-2018 01:34 AM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Michael Thayne (Post 2171244)
The missile shield design switch from Spaceships 3 seems essential here, to stop large warships from being missile bait. But what about ramming? A couple things are unclear to me. First, if your RoF is higher than the number of ramming ships, do you get one hit per ramming ship, or one hit per point of RoF, which can be divided freely among attacking ships? I can't quite tell from the wording of the rule ("Beam weapons that are assigned to point defense may therefore automatically hit a number of incoming ballistic weapons (or ramming spacecraft) up to their maximum rate of fire.")

I suggest that you read this rule in conjunction with "Spreading Fire" on SS1 p.58.
A gunner may choose to divide his shots
among different targets, either attacking multiple
targets, or firing at different parts of a single vessel.
All targets must be specified before rolling to
hit. It imposes an extra -2 penalty per different
target engaged (applied to all attack rolls) when
firing beams or guns, or a -1 penalty per target if
firing missiles. One attack roll is made for each
target.
So your gunner divides his RoF up among targets as he sees fit, and then each shot of group of shots fired at an "incoming ballistic weapon… (or ramming spacecraft)" is an automatic hit. "Automatic hit" as in "couldn't miss at any modifier" ought to mean that every round in the burst hit, because if you would have hit at, say, -10 and have Rcl 1 then you would have hit with ten rounds, right? It'd be foolish for an ease-of-use rules option to drastically reduce effectiveness.

Agemegos 04-15-2018 01:36 AM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Ulzgoroth (Post 2171276)
It's on page 15...of Spaceships 4, not 8.

Spaceships 4 is the one I didn't buy :(

Ulzgoroth 04-15-2018 01:48 AM

Re: [Spaceships] Missile shield vs. ramming: two questions
 
Quote:

Originally Posted by Agemegos (Post 2171280)
Spaceships 4 is the one I didn't buy :(

It's an SM +4 bot with a spinal particle beam and 6g worth of high thrust water fusion torches. If you can extrapolate how SM +4 works, you can probably fill in the gaps yourself.


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