Windows

[Charlie Jones s/v Tehani]

If using plastic, Lexan OR plexiglass, DO NOT countersink for screw heads. Sets up stress risers and WILL eventually split the plastic. Guaranteed.

Instead, over bore the plastic slightly larger than the screw shank, and use a PAN head screw.
The plastic (either kind) has a different expansion/contraction ratio than screws do. If the hole is the exact size, it will split when things heat up or get very cold.

I've done this kind of work- Building, rebuilding or repairing boats since the late 60's by the way.

 

[Chief RA]

TSBB: Your right in all areas except for Lexan cracking. Lexan is the stuff used for bullet proof windows and does not crack. If you must drill holes in plastic then use Lexan.
Chief, IE, plastics, etc.

 

[Brian D]

SaliorRob, I have an 85 Lancer Power Sailor which has six individual rectangular ports. Yes, they leak. Probably because I never really paid attention to what is considered proper care and maintenance. However, nor did the PO of the boat. The ports were not properly installed and used the wrong caulking. My guess is these were replacement ports, but I am not 100% sure.

The best ports or windows is really up to the individual. I personally like my single ports vs. the long plastic windows found on the same boat. There are three boats of the same year and manufacture as mine in my last harbor. Two had the long windows and mine the individual ports. I like mine. LOL

I am going through the process of removing, cleaning, rebedding, and fixing the seal between the frame and the opening ports. It is an extensive process. I just finished cleaning my ports this morning. Tomorrow I go back to the boat, remove the tape, clean the fiberglass, then reinstall the ports. It will probably take all day.

My sealant of choice for this project will be butyl tape. I will add tape to the exposed hull to fill any voids. Then I will insert the inner frame and screw it in place. I will then force tape into the gaps around the ports, place tape on the back of the external frame, place it on and screw it down.

I have read conflicting procedures about screwing the frame on. Two have said do it in stages to allow the butyl tape to ease out and settle. One says to screw it down completely and then clean up the ooz of tape from the frame. So I am not sure which is correct.

Good luck with your project. You might try rebedding the ports first before removing them completely and replacing with a wide window. Look at other boats and see what they have done to see what you will like.

Brian D

 

[Brian S]

If using plastic, Lexan OR plexiglass, DO NOT countersink for screw heads. Sets up stress risers and WILL eventually split the plastic. Guaranteed.

In light of TSBB's comment above, allow me to clarify my previous comment.

The screw holes in the fiberglass of my cabin side were not countersunk. Of course, you should drill pilot holes before screwing into fiberglass. But Maine Sail maintains that countersinking the pilot hole in the fiberglass will help prevent the stress risers in the gelcoat that lead to the spider cracks radiating out from the screw.

If I were going to drill into the plexiglass to fasten with screws, then, yes, I would drill them oversize as TSBB says, to allow for thermal expansion and contraction. And according to what I have read, buy a plexiglass drill bit to do it. The directions that came with my replacement windows said to drill the holes with a dull bit. Others who are more experienced in this than I am say that one should just use a plexiglass drill bit. I think the few bucks would be worth it...