Haven’t gotten around to resealing all of the Beckson portholes yet, but I did get to the front two on the starboard side, that leaves two to go.
The stbd forward one was missing a couple screws and barrel nuts, no question as to why it was leaking. The Beckson barrel nuts are not cheap! Try to buy them for less than $3.50 per nut! If you buy in bulk you can save money on Amazon. Most of the barrel nuts I’ve removed thus far needed to be replaced with new ones due to corrosion or stripped screw heads.
My technique for this job is to take all the screws out and gently use a scraper to start prying the porthole away from the sealant and cutout. Once it starts to come apart I work the porthole from side to side until the sealant gives up. After that I remove the outer frame carefully. I remove all the old sealant from the hull side, porthole and trim piece. For this I use a sharp razor blade and mineral spirits.
To reinstall I use 3M 4000 sealant around the porthole, then set the porthole in place and add another bead around the edge of the frame from outside before replacing the trim piece. Tighten the screws evenly using a small screwdriver and one hand out the hole if you’re by yourself. Snug the screws down in a pattern similar to how you would tighten lug nuts on your car. Now check for a nice bead all the way around on the outside. Add more sealant if needed, fillet the sealant and remove any excess. Add a bead around the outside of the trim piece, fillet and remove any excess.