Marine Audio, subs?

I sure have valued 12 volt's forum for my car audio installation. I have now purchased a ski boat and am looking to upgrade the stereo system. Subwoofers will be the biggest challenge, as i will probably have to add a battery, isolator, and an upgraded alternator.  Does anyone know of any good website that may have advice on marine audio installation. Also, if anyone has any experience about subs in boats i am nervous that being an open air situation will make them much less effective. What do you think about a bandpass box in one of the storage compartments, would that make the sound noticeably louder?

JL makes a great free air sub. I used them on several high end boat installs.

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There is no such thing as free installation!

The last big boat system I did was in 20' Mommba bowrider.  I built a bandpass box out of birch, for single 10" L7 to kicker recommended specs.  In fact when they gave me the specs, I was doubtful of the output.  The box was only like 1.5 cubes. I suspended the box under the drivers side (port side?) of the boat under the steering column for lack of a better term.   By hanging the box, it left the owner about 10" of room to put his feet under the box while driving.  In fact you couldn't even see the box at all.  It was driven by a JL 500/1, and I have never heard another boat that loud.  By firing the port into the bow, it seemed to give a cabin gain affect ala hatchback.  It would be easy to build a test box to try it out. Then you could move it around easily.  Good luck and keep us posted..