I’ll be happy to describe the process. For the record, I did this on my 1983 Ercison 38, which uses a flexible vinyl material as opposed to laminated panels.
Using the old vinyl as a template, I rough-cut the new vinyl about 1-inch larger on all sides. I attached the new vinyl the across the bottom using stainless staples working from the center out, stretching the material slightly as I went. I then went up one of the sides from the bottom up stretching slightly as I went.
Next I prepared the insulation. The idea was to use the thickest insulation possible for that particular area, using alternating layers of Reflectix aluminum insulation and 1-inch 3M Thinsulate material held together with a small amount of 3M 90 Spray Adhesive. The best combination seemed to be Reflectix-Thinsulate-Reflectix. If this was too thick, I would eliminate on layer of Reflectix, etc, or if it was too thin, I would add another layer of Thinsulate, etc. Again, using the old vinyl as a template, I cut the Reflectix Aluminum insulation and the Thinsulate slightly smaller than the old vinyl. Then, I sprayed one side of the Reflectix with 3M 90 and one side of the Thinsulate with 3M 90, let them set for a few minutes, then pressed them together. I then glued another layer of Reflectix to the Thinsulate to make a “sandwich” (or not depending on the thickness needed).
After letting the insulation sandwich cure for a while, I inserted it between the partially installed vinyl and the hull or deck. I found that no adhesive was necessary at this step as the pressure of the finished vinyl would be more than enough to hold the thick insulation sandwich into place. If there was stainless hardware peaking through the deck, I covered it with a thick layer of rubber or a few layers of old vinyl using the 3M 90 adhesive, or I eliminated the outer aluminum layer and placed the Thinsulate side against the deck with Reflectix facing the interior (which is probably the best option if you think you will need to get at the deck hardware anytime soon).
With the insulation in place, I began stapling the remaining 2 sides. I stretched the material considerably as I widely spaced the stables several inches apart. This way I could easily remove staples and start over if creases formed. Once I was satisfied with the shape, I filled in with more staples, then trimmed the excess vinyl and re-installed the old (but freshly varnished) teak trim to cover the staples.
The description below includes new vinyl, but I only needed to replace the vinyl in one small part of the headliner where I accidentally tore it with a wayward drill. For the majority of the boat, I was able to disconnect 2 sides of the old vinyl, rip out the old ¼-inch yellow foam insulation and replace with carefully-measured new insulation.
I’m sure many of you on the east coast will think I’m a wimp, but when the temperature falls below 60 degrees, I fire-up a Dickinson propane cabin heater. The enhanced insulation plus a couple of battery-powered fans stuck to the deck hatches, makes for an extremely cozy cabin that is a pleasure to return to after those nighttime dives during lobster season.