We have replaced almost all the portlights on Nine of Cups over the years. The only ones we hadn't gotten to were the three on the transom. They were crazed to the point that they were almost translucent, and replacing them had been on the to-do list for quite a while. We were recently varnishing the trim in the aft cabin, and noticed that two of the three transom portlights had also begun leaking – nothing serious - but at least a small drip. Now seemed as good a time as any to replace them.
The process wasn't all that difficult. Below, I have listed the tools and supplies I used. It took about 3-4 hours per portlight. It may require more or less time depending on how long it takes to remove the old caulk. You can watch a video that shows how I went about the job at this link.
Small container for decanting the alcohol
¼ sheet 220 grit sandpaper
Dow Corning 795 silicone adhesive and sealer - ~3/4 tube per portlight
24-36 2”x2” squares of paper towels – cut from standard sheets of paper towels
Masking tape – any kind will do as it will only be in place a few minutes
Polycarbonate, clear. We use ¼ (6mm) on Nine of Cups
Variable speed jig saw with fine toothed blade, suitable for cutting plastics. If you don't have a jigsaw, you could also use a coping saw or even a small hacksaw.
Screwdriver (hand or battery)
Razor or box cutter
Metal putty knife
Small trash can with plastic liner