What he/she said.
I believe it is fair that BB's can not simply autonuke a cruiser pointing their way.
It's is cool that the danger of it, is out there. Or something close to.
With the mechanics in question, 27mm Cruisers need to learn the ships with more than 400mm grenades, and keep clear of them.
They can still survive an encounter with a BB and even fight some. But not all.
IMO it is a good step toward removing Overmatch and Autobounce.
Instead they could add a weakness mechanic. Every time you shoot AP the same location on a ship, it weakens.
Increased weakness increases chance of a shell hit hitting a weakspot.
A proc. of weakspot hit lowers the armor value in that hit. Perhaps based on weakness stacks.
As if not bounced, a hit going half way into armor give 1 stack of weakness on that part of the ship.
A hit going allmost through armor give 2 stacks of weakness.
Over time weakness' are repaired away.
A BB could begin penetrading, like Overmatch but only after a while or with help of allies shooting the same part.