I believe it will turn gray over time. I'd talk to a boat person. Lot's of teak is used on boats. I think there is a Teak Oil for it, but like all outside stuff it has to be reapplied occasionally.
Never mind! Early in the morning and only my first cup of coffee. I read Cypress, when I pressed reply, by brain turned to Teak..... forget what I said above. I will now start on my second cup of coffee.