In some ways, that what it feels like to me against the Markgraf, even. Or the Ark Royal. Average hulls and more than 10% in armour is brutal to chew through, and even weak hulls seem incredibly durable with 2 screens and 5% armour.
I'd still like some kind of critical hit which doesn't require chewing through all the hull. Just off the top of my head, let's say that if an individual attack does 6+ points of damage, you roll onthe crit table for that ship. Results might be "lose all portside weapons for 1 turn" or "lose 1 Thrust until repaired" or "steering problem, must turn starboard until repaired" or such.