I have it on good authority that they do float ... but our repairs
couldn't have been made in the water
I've posted some photos of the rudder stocks & bearings, and our repairs
, on our blog here: Why knot?: Grenada Marine - Trading Views...
The top of the rudder is held in place by two brackets, with a bolt key through the stocks that fits into the forward bracket. Under this there is a ring that sits atop the fiberglass
casing the rudder rests in, and again has a bolt that goes through the rudder. Under this is the Delrin top ring/bearing, with the bottom bearing being the brass one in the photos.
If I was going to try to take the rudder out in the water, I would definitely set up our sea drogue
under it ... just in case it didn't float!