So I have this hatch on the boat... need advice...
 

That is two part - fiberglass outside with "clear" insert that allows light to enter.

The clear inside is some sort of plastic polycarbonate/lexan type.

Needless to say over the years - it's crazed - and not so clear anymore - more of a pinky color... .

Any advice on replacing that inside panel? Can I just used a smoked lexan? Any way to make a slight crown in it?

http://forums.pelicanparts.com/uploa...1234995172.jpg

http://forums.pelicanparts.com/uploa...1234995194.jpg

Could you replace it with plexiglass? It's easy to cut with a table saw (or knife if you have steady hands) and pretty robust.

I had a boat with a similar hatch, the frame of the hatch was crowned..Smoked lexan or plexiglass will work. When you bolt the replacement in, it will curve to follow the profile of the hatch..

Just bed the new piece in a bed of silicone.

+1 to what he said /\

Plexiglass/Acrylic is more scratch resistant than Lexan/Polycarbonate (and is cheaper too), however Acrylic will not be as break resistant. Whatever you use, just be sure to drill the holes oversize (and deburr) and do not over tighten the screws so that expansion contraction can occur to avoid breakage/cracks at the screw holes.

If the frame isn't crowned I've seen guys use heat guns to mold lexan slightly. If needed, clamp lexan to frame (out of boat), frame upside down and carefully heat lexan until gravity helps shape.

The only way to make a compound "crown" would be heat. If the hatch frame is flat and you want a hump, you can go N/S or E/W. I would cut some teak in a slight curve to hold the edges of your curvature on 2 sides. Silicone will definitely seal against the weather.

To do a nice silicone job, mask on both sides of the intended bead. Then dip your finger in soapy water to smooth the bead out. Pull the tape while the silicone is wet and you'll have a very nice job.

Thanks guys - that's kinda what I was thinking

real pirates didn't wet their finger for no beads

Just finished this project over the weekend - went with some 3/8 smoked lexan.

Had to trim the edges a little because of the thickness - but dimensionally it's a much more stable piece.
BEFORE
http://forums.pelicanparts.com/uploa...1241445548.jpg

AFTER
http://forums.pelicanparts.com/uploa...1241445618.jpg

Nice job, huge improvement. Weird that the old went pink.

That's the kind of thing that makes me love this place. Someone is always coming up with a little bit of gold.

Very nice.