I am just about done refinishing the original teak parquet floor in the master suite of our Defever 44. Sanded to bare wood and finished with water-borne urethane. Looks great and the sanding removed all the high spots on the edges of the individual pieces. I am not at all worried about durability. The original finish lasted 34 years.
I last varnished my teak parquet floor about 10 years ago. I still get comments from visitors like "I see you have been busy varnishing your floors. They look beautiful". I do have small carpets so you can always walk on a dry floor.