Re: Rudder damage - urgent advice needed
I would be willing to bet that all rudders with a bronze, stainless, aluminum, carbon, you name it shaft have water in them. I don't believe it is possible without extreme cost to keep it from happening. Certainly the 3 I have cut apart all had water in them.
My Etap 26 has an aluminum rudder post. There was severe pitting right above the blade and I was really worried. So I used a dremel with an abrasive disk to cut the center of the edge all the way around the blade. One side fell right off. The other side was heavily glassed to the shaft and the straps that take the torque. The foam core was completely dry, except the inevitable voids that were all full of water. This rudder spent 25 years on a mooring, even in the winter. IT had a big hole from ice too.
Big surprise. The aluminum shaft, straps, and welds inside the blade were bright and shiny like the day it was built! So what about severe pitting right above the blade? I finally figured it out. Bottom paint, copper bottom paint, is death to aluminum under water! The only pitting was where the bottom paint reached the shaft. I ground out all the pitting, and welded it up. Then I carefully filed it round and smooth again.
Stainless though is a different animal. Crevice corrosion from a lack of oxygen inside the blade can really wreak havoc. Considering how easy it is to split a rudder and check it, I think older boats ought to have this done at some point in their lives.
Gary H. Lucas