Lexan is a very different material from glass -- it is much more flexible,
so that the issue is more "will it pop out of the frame" than "is it strong
enough".

It also has long term UV issues. Generally my choice for plastic windows
would be acrylic (Plexiglas, etc.) rather than polycarbonate (Lexan, etc.).
While acrylic is less satisfactory if you're going to throw a brick at it --
it shatters more easily -- it flexes less and has considerably better UV
resistance. (On UV, I should add that if the polycarbonate has the right
coating that we're talking about the difference between 10-15 years life and
30-50 years life as between polycarbonate and acrylic.) Plastics also
scratch more easily than glass, polycarbonate more easily than acrylic. You
have to be very careful to use lots of water when you remove salt.

Tempered glass is, however, the best solution.


--
Jim Woodward
www.mvFintry.com


..
"Adam" wrote in message
...
This particular manufacturer doesn't offer laminated glass, but other
does.
The safety/laminated glass is more expensive, for 1/2" thickness it is 50%
more
(for glass not for entire window).
I do not have price for 1/2" but 3/8" tempered glass it is ~$40Cdn/sqft
Other manufacturers doesn't offer 1/2" and up in thickness or the
extrusion
is
extremely heavy.
Specification for my application says minimum 3/8 and 1/2 is recommended.
As material my spec says Lexan - but I like to go with glass with the same
minimum thickness.
Adam

"Keith" wrote in message
...
Interesting. Do they have an alternate spec. for safety glass? I always
wondered which was better, since tempered was stronger, but if it ever
DID
break, it would be completely gone. Safety glass might break, but the
lamination would hopefully hold it in place rather than just crumble out
of
the fixture.

"Jim Woodward" jameslwoodward at attbi dot com wrote in message
...
I might save you a buck or two, although I told you they weren't
cheap.

The ABS rules for Fintry (tough boat, go anywhere, but not anytime)
call
for
0.4" tempered glass in forward main deck windows and 0.3" in side
windows,
both 28"x36". That suggests that 1/2" glass is substantial overkill
in
your
24x30" windows, as smaller windows take thinner glass. I'd probably
go
with
3/8" tempered glass, if I were you. Or, do a little research and you
might
find that you could go even thinner....

The ABS numbers come from my naval architect, Jerry Gilligan at Jack
Gilbert's office -- they design heavy workboats most of the time.




--
Jim Woodward
www.mvFintry.com


.
"Adam" wrote in message
...
Thank you everybody for you help with windows issue.
After a lot of e-mails to rbb and direct to me, I decided to not go
with
plastic and
automotive industry either.
Yesterday I went to marine windows manufacturer - Beclawat.
They are doing really professional job.
I was surprised how easy it is to bend 3" radius corners with heavy
aluminum
extrusion.
Everything is easy if you have access to proper extrusion, even
could
be
welded nicely.
I was also surprised how expensive it is.
Heavy duty 1/2" tempered glass, fixed, anodized 24x30 approximately
$500
Cdn.
Thanks once again for your help
Adam
"Jim Woodward" jameslwoodward at attbi dot com wrote in message
...
I think Michael was speaking of windows -- the whole installation,
frame
and
all -- made for RVs (caravans in Brit-speak), buses, etc., which
are
to
be
avoided. Fintry had caravan windows installed as part of her 1998
refit,
which we're replacing because they aren't strong enough.

On the other hand, for the most part, glass is glass, although for
marine
use it should be either tempered or laminated -- in that sense,
automotive
glass is just fine.


--
Jim Woodward
www.mvFintry.com

.
"Rufus" wrote in message
...
I have a WS32 with custom dodger using 4 pieces of automotive
glass
the
PO installed in Australia in about '80. It all cleans up very
nicely,
clear as can be. Not sure why it'd be any other way, but maybe
I'm
just
a luck fellow. g

Rufus



Michael Porter wrote:

Cheap, maybe
Automobile windows don't last long in salt water, any more
than
home
windows do.

Michael Porter

Rufus wrote:

Might see if there are any "bolt-in" size automotive windows
out
there.
Trucks and vans would be the likely donors. Getting it from
vehicles
from the mid-late 90's would make it cheap and also it would
likely
to
continue to be readily available for another 5 years or so.

Rufus

Michael Porter Naval Architect / Boatbuilder
mporter at mp-marine dot com
www.mp-marine.com