The rudder head has a lot of movement on its two pivot bolts. I had decided they needed replacing, so after a lot of heaving and propping, I got the top one out and slotted a new one in. Not easy as the clearance is very exact. Lining up the rudder and transom hole was not trivial. After finger tightening the nut, there was still a lot of play. I then tried just tightening the nuts on both top and bottom bolts, and now there is minimum play. They just needed tightening,not replacing. Good to find out in a dry shed rather than on a tidal beach, even worse, at sea. The bolts are in a horribly confined space. You can only get 1/12 of a spanner turn each go, so it takes a long time to get the nut secured. I will replace both nyloc nuts before I launch.