I was thinking just the same thing and came across the old "projects" section that used to be on this website.
I just get blank pages when I click projects now but here is a link to the old section:
http://www.alohaowners.com/projects/projects.htmIf you check the "Rudder & steering post rebuild - Part 1" it mentions that the rudder quadrant is only about 1/8 above the top of rudder tube.
So the gaiter won't work but when I consulted with a friend in the boat repair business he suggested a different solution. He has seen boats where this space is filled by multiple O rings - basically enough so the rudder quadrant presses them together and into the rudder tube. The O rings are coated in a silicone paste (dielectric paste -
doesn't harden, swell the rubber or wash off with water) so they slip against each other and don't get chewed up as the rudder turns.
Unfortunately there is no way to add the O rings (or a conventional shaft seal) without dropping the rudder about six inches. Still, from reading the rudder post rebuild articles it seems the rudder quadrant has serious corrosion issues so maybe it's a good idea to have to remove it.
I was originally thinking of adding a zerk fitting to the rudder tube and using a grease gun and thick silicone paste. If the pressures are not too great this might be enough to keep the water out (and cut down further wear plus make the steering easier/smoother).
Let us know what you end up doing as I plan to fix this issue after haulout this fall.
Chris