Ships are not dry

Wood rot in boats varies by level:
o Fresh water through decks -- rot a problem
o Fresh water from condensation -- rot a problem
o Salt water in the bilge/keel/bottom -- far less a problem

Salt acts as a preservative.

Sikkens do a clear Cetol, and I guess Dutch Oil would be ok?
The risk of picking a bad finish is real, there are some really
quite putrid yellow Cetol colours which ruin the appearance.

Felt a bit sacriledge putting white rubbol on an Iroko gate,
but I'd only done the frame in Iroko, horizontals were pine.

Plenty of places do let wood naturally weather:
o Iroko cladding, red-cedar cladding
o Red-cedar shingles

However for windows most people want absolute longevity.
--
DB.