Our bow thruster was gently losing oil. Though we rarely use it, as we like to anchor everywhere, it is 20 years old and I suspect that there is a shallow groove where the seal sits on the shaft. I have now switched from a 30mm inside diameter to a 29mm so this may do the trick.
Neil, a mechanic in this part of the world ( Kilada, Greece ) has pointed out that if the 29mm still leaks I should try a particular SKF seal which ( in Europe) is only available from SKF in Scotland and which has twin seals, the idea being that each of the two seals will sit just to the side of the groove. I will try that if the leak continues before fitting the new shaft which we have on board.
On a separate note, Neil built his own steel 42 ft boat 20 years ago. He tried to sell pre-Covid. During lockdown he had about 3 hits a day to his very detailed website. On 17th July the UK allowed flights to Greece. The hits on his website immediately went to 600 ( that's not a typo ! ) per day and he sold for the asking price, sight unseen to a guy who is now thrilled with it.
It seems that Covid might be doing wonders for boat sales.
Ian and Judy, Pen Azen, SM 302, Kilada ( waiting to launch, but they are predicting gusts of 50+ for Friday night so....)