Cleaned teak deck and treated it with Boracol. This is a stuff recommended by Hallberg-Rassy. It soaks deep into the tree structure, and inhibits the development of mold, slime and rot. Some of my friends tell me that it also makes the teak keep its brown colour when wet (instead of the almost black colour found on boats older than a couple of years or so), at the same time protecting the silver shade when dry.
It is easy to apply with a brush, but it is amazing how much teak there is on a relatively small boat like this (34 feet), when working this way! The work took about six hours while I had guessed two. It is called optimism.
Soon after applying (the teak is supposed to be clean and dry) the deck looked untreated, in this case as new. After a couple of days (I am writing this in retrospect), I noticed that the colour was much more brownish when wet than earlier. I have also noted, however, that the teak seems to be softer on the surface. When stepped on wet a kind of scratch becomes visible. Some friends of mine have experienced the same thing, and assured me that scratches like this do not run deep. I will follow up on this matter later on.