Plastic Portholes

[SV Demeter]

If you look in this picture of my boat you will see an opening port mounted in the aft most fixed port. I would like to replace this opening port with an all plastic version as I think an all plastic version will be less likely to crack the existing fixed port. The ones being used now have not cracked the fixed port but because their frame is aluminum I fear it more likely to occur than with a plastic framed port. I would also like to add a few more opening ports to some of the other fixed ports and want them to match.

Im looking for a suggested brand of port to use. Im considering Beckson right now but only because they were my first thought. Other suggestions appreciated.

Thanks