[Dakota773]

I mounted a pair of box speaker under the bolsters on my 98 31 Open and they are awesome.  No drilling or hole cutting. They fit a little tight but that's because I added a 2000W amp and needs the extra quality to handle the 250 W/ Channel.  All said though I just screwed them to the bottom (or top if your looking the other way) of the side rail.  The wiring I ran forward and into the combing under the arch. All protected and only a 3/16" hole filled with caulk.  Once under the arch your in the engine compartment and can easily run the wires to your stereo.

You might need to search around for box speakers thin enough (and exterior rated) to fit under the combing, but it's a lot easier than mounting them to the arch. Fusion has some, mine are JBLs, but a few years old.  By  the way my 31 has them in the arch as well, I was adding a 2nd set to get sound in the back while running.

Good luck.

---

FYI, I forgot to note that the speakers are facing down and that the sound reflects almost perfectly off the cockpit floor.  The speakers don't need to face out to get good sound.