I've tried quite a few subs in different setups/boxes on my boat over the years, and can tell you ported facing the hull is the absolute best option. I'm familiar with the Crownline, my brother in law has a pretty nice LPX
Here's a couple vids of my boat with a Sundown zv3 15 on a 2400w amp. Box is 3.4 cube after displacement tuned to 35hz. I've yet to hear a boat with more output.
[video=youtube;5F1ev-dAluA]