Flush mounted windows

[fhrussell]

HI All,
I'm not sure if this has been covered here before, but.....?

I am looking to install my plexi windows without the gasket. I'd prefer to flush mount them. Any tips? The cabin sides are 1/4" with a 1/4" backing for the window to sit against. I could screw or bolt the window through this backing/ flange, and then the window would be flush to the cabin side. Is there a general fastener distance I should use? What are the appropriate sealants? How large should I drill for fasteners? The cabin side is painted white and the window is heavily tinted, so I expect the contraction/ expansion to be an issue.
Sorry, lots-a-questions.....
Thanks again

[dionysis]

Just some general comments:

So as to not create stress concentrations, make sure that the plexiglass is of the same strength as the topsides. This could mean that the plexi will turn out thicker that the topsides. Seach google for the 'coefficient of thermal expansion' of the fibreglass and the plexiglass. If they are close together, and the window is small, you may not have to worry so much. In which case make sure the plexi is a tight fit with the topsides. I would sandwich the plexi between inner and outer backing plates, unless the plexi will be glued in place. It depends on the coefficients of thermal expansion.

Hope this helps