Port Lights (Not windows)

[Phillip]

Now Greg, is that a DISCLAIMER!

Don't forget to put a small SS washer between the acrylic and the base to maintain the seal thickness.

[Dolphin]

Thanks Phil, that makes sense.
One of the main reasons for the failure is that there is a recess in the frame that holds the Perspex and that was a neat fit for the particular sheet I had. If I had have reduced it 3 or 4 mm it may have worked. In any case though the frame is badly corroded. Just another boating job I guess.