I built mine in a weekend. Not to hard to do but very time consuming if you want to get it right. I am running a Rf Punch 12' P2D412 in a sealed box, roughly 1.1 cubic feet. I jigged it out all in cardboard to get my angles and contours of my hull since it is only an 18ft. Stingray bowrider. I glassed the entire box and had to form the right side of the box to the curve in the floor all with glass mat. I siliconed every crack and corner and covered the face with bondo for the cosmetics or it then painted it down, and about 4 coats of Krylon clear coat. I have it pushed by a Dual XIA3145 2 channel amp, and a Kenwood KDC 135 Head unit, which is pushing 4 Polk DB-651's.
Not the ideal setup but it works for me and my budget, and as long as I can listen when at WOT, and have no distort at high volume, I am happy.
Cody: Nice work. Im guessing you have under $100 bucks into your sub box. $30 in MDF and screws and $25 in resin. I count tell how it was finished in the pic's vinyl or painted. But it looks great. Just because your on a budjet dosent mean you cant do somthing real nice. You have to do it yourself but if you ask enough questions here and take your time or ask a friend who might better with tools than you You can build somthing real nice like what Cody did. I like how you used resin and fiberglass to make the funky bend in the box. Nice DYI job on the box.
typical install would be under the drivers dash or observers storage area but with some creativity a sub can be placed almost anywhere it will fit. As far as how to face the sub is subjective and gonna depend on the type of sub, the box, and sub location. The sub on my current boat sounds better faced towards the hull but on my last boat it sounded better facing out towards the transom. Two different brands of subs and two different boats.
The finished picture is all paint and clearcoat. I used bondo to get it all smooth and then painted it with cans of Krylon Fusion to bond with the resin and Bondo, then Cleared it with the same. The color matches the boat gel coat