Spaceships hull armor…solid?

[Anthony]

Originally Posted by Agemegos

Yes, one of you mylar balloons or one of Fred's claymore mines will remove several square metres of the outer few layers of a suitably spaced armour, making an area vulnerable to a follow-up attack. But if either of them were to impact solid armour plate they would make a hole in that just as big or bigger, rupture the pressure containment, and spray high-velocity debris in a plume through the interior of the ship.

If you make your bubble grossly excessively massive, yes, but why would you do that? You want an impactor that's just heavy enough to cause the surface layer to shatter; if it hits a surface layer that's ten times heavier, it's not actually going to do much.

This actually introduces a fair amount of information warfare into the equation: if you know how thick your enemy's armor is, you can tune your warhead to match (it will generally be faster to change warheads than to change armor), if you get it wrong you're going to suffer a significant effectiveness penalty.