Ok, I'll be that PITA naysayer. Consider asking a professional what they would charge to simply cut the holes for you. Trailer the boat to them to save money. You're dealing with fiberglass and making permenent cuts. Are you skilled with fiberglass or gelcoat repairs? I most certainly am not. Several years ago when I needed speaker holes cut for my boat, I ended up trailering it to Best Buy. I called them a couple days earlier, told them what I wanted to do, and they said no big deal. Did the work behind their shop the same day with an aresol cutter I think. The four speakers came out perfect, and the price was super cheap. And since I was dealing with Best Buy, I knew they'd be insured to fix anything they F'd up. I have cut my dash and installed electronics before, but there you are talking straight cuts. I can hardly draw a circle, let alone cut one with a saw through fiberglass. If you are going to attempt it yourself, maybe consider getting some scrap plywood or something of similar thickness to what you'll be cutting and try a few practice cuts. Make copies of your template if that's what came with the speakers. here