Yooperdad,
As in the previous post I also put in access ports in order to mount downriggers on my Overnighter 20.
Regarding the hardware installation, access ports enabled through-bolting of Scotty 1025 side gunnel mounts for a more solid installation. Scotty 1026 pedestal swivel mounts were then SS bolted on top of the gunnel mounts. The swivel mounts enable me to swing the 60" booms forward or aft and troll with with booms extended to the side (normal operation). Also adjustable to different angles which can be useful when in tricky currents. Swivel mounts allow you to swing the downrigger gear out of the way when landing larger fish.
For the electrical side of the installation the access ports provide quick and easy access to the fuse holders. Marinco SS electrical connectors are flush mounted adjacent to the access ports. Much less corrosion & maintenance with SS connectors than previous brass connectors. I used sealed waterproof "blade" type fuse holders for the past 5 years with no problems. I found these to be less subject to corrosion and failure than in-line spring loaded fuse holders.
This particular installation has worked well for me over the past 5 seasons - salmon fishing on the "wet coast". Previous installation was a painted aluminum bracket bolted to the hull inside the gunnel of an aluminum boat. Not as clean an installation - not something you want to bump into, flaking paint etc.
Having some difficulty uploading a photo-have posted in album - Overnighter 20, Reel Adventure.
Hope this is useful to you.
Phil a