Nice. I don’t see why you can’t mount under the bridge. Just pick the side you can reach from the ground so you don’t have to climb up to reach it (I’m short, I can’t reach mine without a step up). When you drill, start off with drill in reverse to get through gelcoat for cleaner hole and prevent cracking. Then drill as normal. I have a main/jump switch for main power and a second one for power poles in addition to the one that came with boat mounted on battery. Watch for charger plug wire under bridge. At least, that’s where mine was on my Caracal pre STS. Good luck.