How to make space combat more survivable?

[Aldric]

So, I tried making a SM+9 Unstramlined hull at TL 9

Armor is DR 20, but a tertiary battery has 12cm guns that deal 6dx30 damage, and that's with default relative velocity, and there are 30 of those in a battery, and they fire 10 times in a 3 minute round.
The ship has 100 HP
Even one of those basic projectiles will blow up the ship.

So, unless you want all space combat to end in a draw with everyone dead (or in escape pods if they're lucky) I guess you need to rework all numbers.

Unless someone tells me I got everything completely wrong...

[Fred Brackin]

Originally Posted by Aldric

So, I tried making a SM+9 Unstramlined hull at TL 9

For a Star Wars-like result you ought to be working at TL11^ so you can have Force Screens and you won't be trying to use kinetic energy weapons.

[Varyon]

Originally Posted by Aldric

So, I tried making a SM+9 Unstramlined hull at TL 9

Armor is DR 20, but a tertiary battery has 12cm guns that deal 6dx30 damage, and that's with default relative velocity, and there are 30 of those in a battery, and they fire 10 times in a 3 minute round.
The ship has 100 HP
Even one of those basic projectiles will blow up the ship.

So, unless you want all space combat to end in a draw with everyone dead (or in escape pods if they're lucky) I guess you need to rework all numbers.

Unless someone tells me I got everything completely wrong...

Well, that SM+9 vessel can also have a tertiary battery filled with VRF lasers, with RoF 30,000 in a 3-minute round (as opposed to the RoF 300 of the guns). Assuming, say, skill 12, proximity warheads, and fixed mounts, the gunners will be rolling against skill 26 (base 12, +8 RoF, +4 proximity, +2 fixed mount, -9 sAcc, +9 SM), while the point-defense lasers will be rolling against skill 28 (base 12, +18 RoF, +0 sAcc, -2 SM). The gunners can hit with, at most, 6 rounds (on a roll of 6 or lower, which has MoS 20 - enough for 5 extra hits for the Rcl 4 weapons used). As the lasers have Rcl 1, the point defense gunners only need an MoS of 5 to negate the attack, meaning so long as they don't fail outright (from rolling a 17 or 18), they'll readily block every single shot (in fact, they could get away with only using 1600 shots, for skill 21). A more typical attack is only going to land 4 hits, meaning the point defense gunners only need MoS 3 - skill 19 will guarantee that so long as the characters succeed at all, and that only needs RoF 400 to pull off (and if PD fails, there is a chance to avoid damage with a Dodge, although that will need MoS 3 to avoid all hits).

Granted, the above requires you to sacrifice two modules for a power plant and a (ideally central-mounted) turreted laser battery, but sacrificing a bit of armor is probably worth it there. The lasers are also going to be useless against other vessels - they deal only 1d+2 dDamage - but their purpose is defense, not offense, and any hit automatically kills a bullet/missile.

EDIT: I failed to account for the SM's of the targets themselves. The above has been updated.

[Rupert]

Originally Posted by Aldric

So, I tried making a SM+9 Unstramlined hull at TL 9

Armor is DR 20, but a tertiary battery has 12cm guns that deal 6dx30 damage, and that's with default relative velocity, and there are 30 of those in a battery, and they fire 10 times in a 3 minute round.
The ship has 100 HP
Even one of those basic projectiles will blow up the ship.

So, unless you want all space combat to end in a draw with everyone dead (or in escape pods if they're lucky) I guess you need to rework all numbers.

Unless someone tells me I got everything completely wrong...

Check to see if there's a newer version of Spaceships available for download, or if you're using a hard copy, check for errata. My copy says the guns should be doing 6dx3. Also, have you calculated the likely hit chances of those guns? Guns have miserable accuracy.

And, as Fred says, TL9 isn't 'Star Wars'. It's slightly better than modern tech, in space. So you're looking at a small frigate (SM+9 = 3,000 tons mass), with little armour, firing large salvos of hyper velocity 120mm shells (so tank gun rounds). It's not too surprising that each hit has a ~50% chance of trashing a compartment, and a couple of them will put the ship into negative HP.

[Rupert]

Originally Posted by Varyon

Well, that SM+9 vessel can also have a tertiary battery filled with VRF lasers, with RoF 30,000 in a 3-minute round (as opposed to the RoF 300 of the guns). Assuming, say, skill 12, proximity warheads, and fixed mounts, the gunners will be rolling against skill 15 (base 12, +8 RoF, +4 proximity, +2 fixed mount, -9 sAcc), while the point-defense lasers will be rolling against skill 30 (base 12, +18 RoF, +0 sAcc). The gunners can hit with, at most, 4 rounds (on a roll of 3, which has MoS 12 - enough for 3 extra hits for the Rcl 4 weapons used). As the lasers have Rcl 1, the point defense gunners only need an MoS of 3 to negate the attack, meaning so long as they don't fail outright (from rolling a 17 or 18), they'll readily block every single shot (in fact, they could get away with only using 100 shots, for skill 19). A more typical attack is only going to land 2 hits, meaning the point defense gunners only need MoS 1 - skill 17 will guarantee that so long as the characters succeed at all, and that only needs RoF 25 to pull off (and even if the PD fails, the vessel still gets a Dodge, and only needs MoS 1 to avoid any damage).

You missed out size modifiers, which mean the shells hit 4 times on average and might hit 6 times. The lasers will take a -2 vs 12cm shells, so they need a bit more RoF than you calculated. Still, RoF1600 will stop even the best attack except on a 17-18.

Note that your calculations are also lumping all the weapon in together, which is illegal by the RAW unless they are fixed mounts (which is inadvisable for PD systems). Besides, pumping all the attacks together is foolish for the shells. They get Skill-12 + 2 (fixed) + 4(proximity) -9(sAcc) +9(target SM) +2(RoF) = 18 per weapon firing singly, and so will usually hit 3 times each. Firing each separately thus gives 90 hits, rather than the 4 times they'd get all firing as one system.

As has been noted in the past, the autofire rules don't really work well here.

[Varyon]

Originally Posted by Rupert

You missed out size modifiers, which mean the shells hit 4 times on average and might hit 6 times. The lasers will take a -2 vs 12cm shells, so they need a bit more RoF than you calculated. Still, RoF1600 will stop even the best attack except on a 17-18.

I noticed and updated that as you were typing this (although my initial update had the wrong RoF's, but that's been updated now).

Originally Posted by Rupert

Note that your calculations are also lumping all the weapon in together, which is illegal by the RAW unless they are fixed mounts (which is inadvisable for PD systems). Besides, pumping all the attacks together is foolish for the shells. They get Skill-12 + 2 (fixed) + 4(proximity) -9(sAcc) +9(target SM) +2(RoF) = 18 per weapon firing singly, and so will usually hit 3 times each. Firing each separately thus gives 90 hits, rather than the 4 times they'd get all firing as one system.

As has been noted in the past, the autofire rules don't really work well here.

Yeah, GURPS autofire rules break down here, but most players aren't going to be interested in having 60 (!) rolls to resolve the guns vs PD. Still, we're looking at 18 for each gun (and +1 hit per MoS 4) and 20 for each PD laser (and +1 hit per MoS), so the lasers still have a marked advantage. Indeed, an average roll for the laser will negate 9 hits, so you'd expect to only need 10 of the lasers to actually attack to wipe out all 90 hits. On average, one such frigate can survive the attacks of 3 identical frigates, thanks to its PD lasers.

[Aldric]

Well... At least now we're using actual numbers.

My feeling when I saw the damage table for guns was "this is not scaled" glad my feeling was close to the truth.

What does 6dx7 for 3cm guns (VRF 12cm guns) become? Some 4d?

Since it seems single shells don't hit the target and betting on a critical attack or a critical fail on a defense roll doesn't seem like a viable strategy, just fill space with metal...

Now, 4d won't usually penetrate even a single layer of armor... But numbers are looking better

[Rupert]

Originally Posted by Aldric

Well... At least now we're using actual numbers.

My feeling when I saw the damage table for guns was "this is not scaled" glad my feeling was close to the truth.

What does 6dx7 for 3cm guns (VRF 12cm guns) become? Some 4d?

Since it seems single shells don't hit the target and betting on a critical attack or a critical fail on a defense roll doesn't seem like a viable strategy, just fill space with metal...

Now, 4d won't usually penetrate even a single layer of armor... But numbers are looking better

Here's what you're looking for: http://www.sjgames.com/errata/gurps/4e/spaceships.html

Don't forget that if you use a contact attack, not a proximity one, non-hardened armour is halved, so those 4cm shells will penetrate a single layer of dDR20 armour most of the time if it's not hardened. IF it is, use proximity attacks, and hope to get lucky.

[Agemegos]

Originally Posted by Rupert

WWII naval combat had quite a lot of hammers and eggshells going on, though. World War One might be a better model of attritional damage, aside from those embarrassments the RN had at Jutland.

Yeah, WWI might be better for Star Trek. Star Wars "space" combat is very much WWII, though.

[Rupert]

Originally Posted by Agemegos

Yeah, WWI might be better for Star Trek. Star Wars "space" combat is very much WWII, though.

Aside from large (but not huge) ships seeming to be missing serious anti-ship weapons so they have to slowly pummel each other's shields and then outer hulls to ruin before finishing each other off. It's like WWII battleships armed with cruiser guns.

Thinking about it, Star Wars is almost age-of-sail ships, but with WWII aircraft thrown into it. So ship vs ship just isn't very effective with big ships (because for some reason they refuse to use drones or fighter-grade torpedoes). This also explains why massive space stations work vs ships - they are shore fortresses.