Keeping the original windows:

Wet-sanded starting with 400 grit and gradually worked up to 1200 grit. Then used both coarse and fine fiberglass polishing compound and finished off with a plastic polish. Not the same as new windows but a huge improvement.

Replacing the windows:

According to Mike Evanovich, it was a very simple and gratifying project

1. 1.Went to “TAP Plastics” and chose smoke polycarbonate (PC or by the trade name Lexan)
   

2. •I chose PC because it is hard, so it machines well and the edges can be easily polished
   

3. •PC is more scratch resistant, but it also cracks readily if stressed (Tradeoffs…)
   

2. 2.I removed my old windows and cleaned the windows and the boat thoroughly with 3M adhesive remover (And Finesse-it on the fiberglass – or any Non-wax cleaner-polish)
   

3. 3.Using the old windows, scribe the pattern directly onto the protective paper liner of the new PC
   

4. 4.Important Step---Transfer the EXACT hole pattern to the new PC by using the old window as a drilling guide – Used a drill press to drill plumb.  This step will allow you to reuse the existing mounting holes in your boat.  The edges are not so critical since it overlaps the fiberglass quite a bit to form the seal once bedded – Drill all holes at this time
   

5. 5.Cut out the new window with a band or jig saw with a NEW Blade (OF course, keep the protective paper liner on throughout the entire machining process)
   

6. 6.Important Step---Dry fit the windows (with all hardware – snug – no not tighten) – From the inside of the boat with a very sharp pencil, trace the outline of the cabin cutout directly onto the protective paper liner – Why….see below
   

7. 7.Important Step--Countersink all mounting holes with a drill press to the proper depth allowing for a FHS SS grommet – The CS should be slightly subsurface when the flathead screw/grommet are pulled taut
   

8. 8.Now grind the edges of the perimeter of the window to eliminate any waviness – use a bench grinder with a perpendicular table to ensure you leave a square edge.  The windows lap the cabin, so accuracy is not as important as cosmetics in this step.  The only thing to pay attention to is the mounting holes since they are close to the edges of the new window – keep a consistent distance from the mounting holes to the edge.
   

9. 9.Now roll the edges with a new full round-over router bit using a laminate trimmer.  Pay attention to the mounting holes since they will come very close to the sweep of the router.  The routed edge should not protrude into the countersink area
   

10. 10.Polish the edges with 1000 grit sandpaper and Finesse-it
    

11. 11.Dewax and polish the mounting area in the boat – Have all hardware, sealants ready (Use nylocks nuts on the interior since the windows will be snugged, not torqued)
    

12. 12.Important Step---Carefully cut the protective paper liner with a new micro exacto blade along the scribe line drawn from the dry fit of the window
    

13. 13.Remove only the cut  perimeter of the interior protective paper liner – leave the inner section intact (as well as the entire outside protective liner)  This step is important since it provides a masking shield for silicone on the interior
    

14. 14.Apply 3m silicone sealant to the freshly exposed PC ring – use a spreading tool to level the bead to a consistent depth of approximately 1/16” (Give or take – The goal is to have 100 coverage without abundant excess to trim/clean)
    

15. 15.Insert the window and fasten the hardware tighten sequentially with an even tension pattern over all fasteners.  The adhesive will squeeze out from the Lexan in the inside and outside – this is a good thing
    

16. 16.Remove the protective paper from the OUTSIDE only.  Inspect the outside surface viewing through the Lexan to ensure that the silicone forms a continuous barrier with no gaps – Do NOT clean up the silicone now – Tempting, but do not clean it up now
    

17. 17.Snug the nylocks nuts from the inside – do not torque.  The silicone holds the window in place, the nylocks prevent the nuts from backing off – do not torque the nylock nuts – use an open end wrench, not a ratchet or pneumatics here
    

18. 18.Do NOT remove the inner protective liner – wait 24 hours for the adhesive to cure
    

19. 19.Once a day has passed, carefully trim the interior silicone and remove the hardened bead – now remove the inside protective liner
    

20. 20.Carefully trim the exterior silicone not to scratch the gelcoat and remove the hardened bead