Capital scale equivalent; the Aesir/Vanir has 25 points of standard-scale SI, which translates as three whole points of capital-scale SI (single digit).
Ah thanks for clarifying that you were talking about single digit SI
, because your first post said armor:
The armor, yes, but not the SI; since PWS SI is still at standard scale, they rarely have more than single-digit capital scale armor equivalent. Since they also have only four armor facings (versus the six of a warship), their armor will not last as long either.
I thought you were saying that because of their low SI they had single digit capital scale equivalent armor, which just wasn't true.
Isegrim? 21 standard = 3 Capital, Taihou? 30 standard = 3 capital. Single digits.
Besides the Castrum, what PWS has double-digit capital-scale equivalent SI?
Compare to warships in the modern environment; the Fox has 100 capital points of SI, the equivalent of one thousand points of standard-scale SI; it has more SI than most PWS have in both SI AND armor.
As I have pointed out in other threads, any ship that closes with a capital warship needs to be able to take it out in one turn and survive return fire. Range is a big thing; if the warship can engage your PWS before you can engage it, you are in trouble. Only the smallest, weakest, and/or demonstrably obsolete warship designs are vulnearable to the most powerful PWS that can be fielded (Vinnie, Zec, Carrack), anything larger has at least parity, and even larger classes can eat Castrums for breakfast.
The fox is probably the most heavily armored light warship, definitely not the average. But lets look at SI and armor values together and compare them to the damage those ships dish out:
SI: 100 capital
Heaviest Armor Facing: 70 capital
Max attack (FR/RBS/AR): 60 capital damage
Max with optional waypoint and bearings only capital missile rules: 64 capital damage
SI: 15 capital
Heaviest Armor Facing: 131 capital
Max Attack (Nose/FR): 110
Max with optional waypoint and bearings only capital missile rules: 171
+Naval C3 and Quirks giving it more bonuses at range.
I would put my money on the castrum winning that matchup more often then not. Not only will the castrum be hitting SI on turn one, and getting the resulting crits, but the capital missiles will also be getting crits as well. The Fox would take 270 damage to destroy utterly, and that would take the castrum two turns to achieve, meanwhile the fox would need three turns to do the same to the castrum (without optional rules involved, it would be even at three turns each for total destruction). And the fox is the most heavily armored of the small warships.
Lets look at some other designs, other than ones you called out:
SI: 50 capital
Heaviest Armor Facing: 55 capital
Max attack (FR/RBS/AR): 113 capital damage
SI: 40 capital
Heaviest Armor Facing: 40 capital
Max attack (Nose/FR): 82 capital damage
SI: 46 capital
Heaviest Armor Facing: 30 capital
Max attack (FR/RBS/AR): 87 capital damage
And some Pocket Warships:
SI: 2.1 capital
Heaviest Armor Facing: 67 capital
Max Attack (Nose/RW/LW): 52 capital damage
SI: 7.5 Capital
Heaviest Armor Facing: 81 Capital
Max Attack (Nose/FR): 107
The 8500 ton Isegrim is a little worse, but comparable to the Inezuma and Fredesa, ships twenty times it's size. A Tiamat would hammer those same two warships, with a mutually assured destruction in two rounds.
As it stands light warships should fear big pocket warships, and big warships should fear small pocket warships, but there is definitely a place for both types.
Of course if more ships took high SI or maxed out their armor (or even came close to it) like the fox does, this might be a different story.