We used Semco for many years, after giving up on teak oil. Since then we have migrated to Cetol and finally to proper
varnish. However, we did not have teak decks.
If I were to deal with teak decks, I would try Semco, which—as an earlier poster stated—is easy to prepare for a recoat. Anything else mentioned is much more work. Whatever you use, there will be
maintenance. Semco is no exception, but is by far the easiest to maintain in our experience. It isn’t
varnish by a long shot, but it will protect the teak.