I've tried waterline shots, yes. With that %$^# eloc yesterday I plastered somewhere upwards of 200 rounds into her bow waterline, and just got my efforts laughed at.
I'll keep trying it out though.
Visibly it looks as if the rounds just visually impact with no damage impact; like deck gunning a lighthouse. --grins-- I'm wondering if the damage zones for the ship hulls and superstructures were made to be moderately invulnerable to flak attacks. Guess I'll find out.
Also, does anyone have any idea where I should try looking to make ships auto-attackable by flak guns, like you can do with the deck guns?