Here's a sailboat hatch installation I did. Solid teak frame and trim. Notice the deck's camber (curve) and the slip-feathers used to hold the mitered joints tight. The outer portion of the frame got painted to match the deck; the inner portion got varnish.

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[Linked Image from i.postimg.cc]

"There's more to optics than meets the eye."--anon

"...most of us would be better off losing half a pound around the waist than half a pound on our rifle."--dhg