Re: [PSUBS-MAILIST] Thanks For Answering But that wasn't really my question.

[Ray Keefer <Ray.Keefer@Sun.COM>]

Hi Clipper,

> Why do most submersables use polymethyl methacrylate reather than Lexan?

Because extensive destructive testing has been done on polymethyl methacrylate.
The research was published in the book:

Title:  Acrylic Plastic Viewports
Author: Jerry D. Stachiw

Pub.:   Marcel Dekker, Inc.
        270 Madison Avenue
        New York, NY  10016 
Pages:  
Year:   
ISBN:   
Cost:   $100 original price, $200-$240 for reprints, don't know used price
Synop.: Very detailed discussion into acrylic viewports. This topic
        was Jerry's lifes work. Complete with charts and tables
        derived at via imperical tests. Including destructive
        and cyclical testing.
        
     
While Lexan might look like a useful material there just hasn't been the
testing cycles on it to prove it out. On your sub you will use what you want.
To be safe you will either need to do extensive testing on Lexan or use a
material like, polymethyl methacrylate, that is now well understood.

Regards,
Ray