Is spaceship armor useless?

[vicky_molokh]

Originally Posted by ericbsmith

The Armor/Volume rule is from Pyramid 3-34 along with several other rules tweaks for Spaceships.

Essentially you get a multiplier to dDR because a ship with a large percentage of it's mass in Armor is going to have a reduced volume because of Armor's high density, and a smaller volume ship has less surface area which will increase the Armor's thickness and thus it's dDR.

Which is totally irrelevant for ships other than flying bricks.

[Anthony]

Originally Posted by vicky_molokh

Which is totally irrelevant for ships other than flying bricks.

It's hard to find a period where armored craft were less than around 50% armor by weight.

[vicky_molokh]

Originally Posted by Anthony

It's hard to find a period where armored craft were less than around 50% armor by weight.

The problem isn't that you can't build a flying brick. You can. The problem is that below flying brick level, you might as well make your ships out of cheap ceramic, as long as it can survive reentry (not the same thing as combat damage). The difference between 0, 1 and 2 armour systems on a side is negligible for survivability purposes - either way the ship is dead or crippled in one hit. The tradition to submit builds with 3 armour systems is just that - tradition, even a single armour system to make a streamlined, reentry-capable craft.

And at TL11, a force shield is so much better than armour that it isn't even funny. (Which is a reason why I think the ^ sign should be worth a TL or two for balance purposes, not the way it is now.)

[Ulzgoroth]

The uselessness of armor depends on what's hitting you. If blunting low-powered beam weapons and maybe a small-caliber autocannon is useful, you can do some good with a modest amount of armor. If you need to repel fire from spinal-range beam weapons and missiles, then you can forget it.

[vicky_molokh]

Originally Posted by Ulzgoroth

The uselessness of armor depends on what's hitting you. If blunting low-powered beam weapons and maybe a small-caliber autocannon is useful, you can do some good with a modest amount of armor. If you need to repel fire from spinal-range beam weapons and missiles, then you can forget it.

Let's look at a generic TL10 SM+10 ship. 150 dHP.

A layer of Nanocomposite gives 30 dDR.
A single Tertiary missile with no warhead to speak of hits for 6d×7(2) worth of dDamage. That's an average of 132 injury past DR.

For a proximity-fused warhead, injury becomes 117 . . . per hit. Since proxdet gives +4 to hit, that means that on average, there are 5 hits instead of one. Or an average of 585 injury per attack.

That's if the missile flies at 1 mps. Assuming it accelerates more or starts at a higher relative velocity (extremely likely), damage will be appropriate.

You need 3-4 armour systems (dDR90-120) on your targeted side before you can claim to no longer be shredded by Tertiary ProxDet missiles. At 1 mps. You're still likely to be one-shotted by a sufficiently fast dummy (kinetic) warhead. After all, those 120dDR become 60 vs. normal missiles, which is a laughing matter for a Major battery (6d×12, or average 252 damage at 1 mps).

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Incidentally, autocannon's minimum speed is 1 mps, but damage is half that of missiles. So a Tertiary no longer one-shots armoured craft, but that's about it.
A Tertiary particle beam does 2d×5(5) burn sur, and thus average dDamage of 35 . . . but those 120 dDR become 24. Against the original single-layer (dDR 30), it does 29. Sure, not a one-shot kill, but this is a tertiary, and a beam, thus PD does not apply.

Now, I'm pointing at missiles because for what they do, they're extremely cheap and reliable. Even nukes cost many times less than the hypothetical missileboats that launch them. An SM+4 Control Room, Major Battery and three armour systems cost almost $200K. A nuke costs $50K (for 4d×1000, which is enough to cripple an SM+21 vessel with a layer of Nanocomposite, or an SM+19 one with six layers, before the density bonus).

[Flyndaran]

It's useful against radiation, especially long term but of course gurps doesn't deal with that.
Realistically, spaceships are glass cannons. When you decide to go cinematic, you could just multiply dDR by whatever number you like for the style you want.

[vicky_molokh]

Originally Posted by Flyndaran

It's useful against radiation, especially long term but of course gurps doesn't deal with that.

Originally Posted by Flyndaran

Realistically, spaceships are glass cannons.

Well, TL8 civilian reentry craft certainly are (minus the cannon part). It's hard to tell what will happen in 100+ years.

Originally Posted by Flyndaran

When you decide to go cinematic, you could just multiply dDR by whatever number you like for the style you want.

I'd actually go further than that, modifying system crippling thresholds, death checks etc. And I'm inclined towards ablative or semi-ablative armours, as they make combat more gradual (and maintenance of mostly-just-armour ships more justified).

[Flyndaran]

While not realistic, that is the by far the most common spaceship combat style in story.
How ablative armor works probably depends on the weapons used in setting. Physical armor could act as one more cost the adventurers need to stay aware of.
Energy shields give the ship's engineer more to do in combat and yell about needing more power.

Ooh, sites of major combat could have high levels of armor dust screwing with things.

[vicky_molokh]

Originally Posted by Flyndaran

While not realistic, that is the by far the most common spaceship combat style in story.

Yeah, so it's rather sad that SS doesn't have switches to make such a style out of the box. In fact, I think it still isn't very good for it without houserules, even after all the expansions and pyramids.

Originally Posted by Flyndaran

How ablative armor works probably depends on the weapons used in setting. Physical armor could act as one more cost the adventurers need to stay aware of.
Energy shields give the ship's engineer more to do in combat and yell about needing more power.

Again, shields are somewhat boring the way they are in RAW.

[vierasmarius]

It's been mentioned before that all Spaceship armor is weak for its mass when compared to same-TL body armor. Presumably this is because it's Cheap; you could multiply DR by x1.5 and Cost by x2 (effectively boosting armor TL by 1) and it would remain balanced. That may not be going far enough though. Double or triple DR for no cost increase (and maybe even triple or quintuple DR at x2 cost) would be appropriate in a Space Opera game.

Semi-Ablative and Ablative DR also fit much of the fiction (especially video games) and can be used to justify still-higher DR. Based on their value as limitations, SA would multiply DR by x1.25 while Ablative multiplies by x5. You can also make Force Screens fully Ablative, getting x4 DR (since they're normally SA). Combine that with the above across-the-board DR increase and ships might actually be able to trade more than a couple blows.