There are lots of floating saunas in Oslo. You can rent them and float them off somewhere to enjoy the sauna and the cold dip in the fjord afterwards. Lots of people just keep them harboured up close to the quayside though, like this one, which our daughter tells us is the original Oslo Fjord Sauna, made up of all sorts of left over bits of wood. It has a new 'extension' at the back. We didn't try one out!
One glance and the word "ramshackle" came to mind. Not sure I'd trust this! The last thing you want to have happen is to be in the sauna and see pieces start to fall off! hehe I like the peek inside with the patrons there- brave souls in my opinion!