I'm playing the Narwhal in RFB (with a fix for the nonexistent crew) and man, those 6" guns are maniacal.
I sank a couple merchants within a few minutes of opening fire, and, a patrol boat that looked like an akikaze destroyer O_O
with RFB's damage model...it's an accomplishment, and a hats off to keltos and peabody, who made the guns work.
speaking of which, Keltos, have you tried angling the guns (forward gun up 1-2 degrees, stern 2-3 degrees down) so they are flush with the deck? if you don't get what I mean the pictures of the White Narwhal shows what I'm talking about. makes for good pictures