"Brian D" wrote in message news:UZLad.231664$D%.200791@attbi_s51...

A portlight is a porthole designed to let in light ...from the sun (or a
curious neighbor's flashlight). It's not a light fixture.

gaspOh, no! I though it's purpose was to let OUT light, so that it
stays relatively dim & romantic below...or to see OUT to starboard or
port while speed-using the head when singlehanding in crowded harbors
on autopilot. Now if it lets light IN, then I have to keep CLEANING
the main saloon, and have NO excuse for misreading charts, and will
get NERVOUS if I can see ALL those boats while trying to relieve
myself or cook, this is a very bad idea...NOW I know why they used
plastic that CLOUDS, thank God for UV degradation!

Poly carbonate comes in many grades. The untreated grade is the least
expensive. The treatment applied can be on one side or both. Treatments can
vary as well. You can have just a UV treatment or a hardness treatment that
is alsoUV resistant. The last variant is the most expensive. I am going to
venture a guess. Either the manufacturer used cheap poly or you trashed the
coating by using an abrasive polish. You are definitely suffering UV
degradation. Your choices are to continue polishing forever, replace the
poly panels with the appropriate grade. Or buy new portlights. Please note
that I did not specify using armor glass and that is the best, but it is
only applicable to wooden and metal boats, not FG, as they will shatter with
hull flex.
Steve
wrote in message
om...
I have long been curious as to why the polymer lights on my boat
become cloudy relatively fast, whether near the sea or not & whether
under cover or not. It polishes off fine with a bit of work, but I
never see this occur in other acrylic or lexan windows I have around
my place, and it is a minor annoyance. Is there one particular type
of clear polymer which clouds up like this? If left for months, they
will become only translucent until repolished.