Hi navelfuzz i think ive put this on here somewhere before but here goes with rudder seals.
aquire some silicon fuel tube.... cut a short length and slide it down rudder shaft until it reaches the tube
Now stretch the silicone over the tube and " voila " one ready made rudder seal.
make sure that the silicon is only a snug fit on the rudder shaft so that it can slip inside the silicon.
if the rudder is allways above water line then no problem , but if unsure the above method works for me,
and as they say " its as cheap as chips "
regards.....bob.