I'm spending this summer fixing up my Pocketship, and one of those is the portholes. During construction I made my portholes with a flange on both sides, so I could avoid drilling the plexiglass. Well, I'm going to remove the sun-damaged exterior flange and make mine exactly as in the plans. I'm confused however about the "marine bedding compound, preferably in black" the manual talks about. I have seen posts talking about butyl tape vs. silicon, and read on one retailer's site that for portholes, silicon is preferred (?). At this point, I think my default would be to paint the exterior-facing flange surfaces black (to hide the plywood behind it) and use clear silicon sealant. The black-tinted marine compound I have seen is <adhesive>, which I don't think I want.
If you have any advice on that or on what you think I should do, I'd be all ears!