I'm not a boater but I am a woodworker and was wondering if anyone can tell
me about this "starboard" or marine grade plastic sheet.

I've never used it before.

I'd like to know how well the edges can be finished on the material, with a
sander, buffer, jointer? or?

I can finish acrylic edges fine but have yet to meet a plastic that will
give a good finished edge......but I had someone suggest this Starboard
stuff. (would like 3/8" thick or 1/4")

Thanks.