Quote:
Originally Posted by delmarrey  |
Have you asked yourself why Bomar puts support bars under the lenses in their Lexan fitted hatches - the clue is in my post? It is not self supporting for other than small areas and small loads due to its elongation when loaded. Apart from anything else that presents sealing problems. (Although at least one hatch manufacturer, can't think which one at the moment, gives the choice of thinner lensed acrylic hatches with support bars, or thicker acrylic lenses without supports)
You may also like to clarify what Bomar use for lenses in all their other hatches apart from the Cast 100 line linked to?
For hatches you will find that builders such as Freeman, Lewmar, Maxwell, Atkins & Hoyle, etc all use acrylic for hatches (or in the case of Freeman, choice of acrylic or tempered glass, but not polycarbonate, and in Bomar's case mostly acrylic).
As far as I know they all mostly use acrylic or if not then tempered glass for portlights (Freeman, who is probably the best manufacturer of the lot, does use Lexan for its cheapest "Yacht Premium portlights though, but glass in most (all?) others and Bomar uses Lexan in (all?) portlights).
I cannot imagine anyone using Lexan for other than very small fixed windows but seems amateurs do - but there again I have also known them to use plain annealed glass and laminated annealed glass too, so maybe Lexan not much of a surprise
.
For storm shutters where Konani used 3/4" (think it was) I would have no difficulty with, distortion and sealing is not a real issue and shock loads are what one might want resistance to. It has obvious benefits compared to the alternative of plywood.
Of course, people can use whatever they like (but they will have a very limited choice if they want Lexan), but any new build I managed would never be allowed to be fitted with Lexan hatches or windows (in fact the windows are always tempered glass because nothing else is allowed in them
).