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Lost Rudder/Post Corrosion - Mainsheet Article

Posted: Thu Mar 05, 2020 3:11 pm
by Captain Kirk
I was amazed by the facts presented in the recent Mainsheet article. The damage that stray currents can do is significant!
I pulled out the engine instrument cluster yesterday to inspect the area around the steering chain, no apparent problems and I did put an extra zap strap around the wire harness.

Definitely going to look closely at the rudder post that is somewhat visible through the gap between the rudder and hull, on the next haul out. Although I'm not sure what I'll be able to see.

Has anyone heard of similar failures on a Catalina. After 18 years with our C320 and now 4 years with Sand Dollar I've never heard of this type of failure.

Re: Lost Rudder/Post Corrosion - Mainsheet Article

Posted: Thu Mar 05, 2020 5:26 pm
by wolfe10
No question that electrolysis can eat up a rudder stock if stray 12 VDC is able to "ground" through it, particularly in salt water.

And, any 12 VDC positive not isolated from surrounding metal in the pedestal/instrument area is electrically connected to the rudder through the housing, steering gears, cables and steering quadrant.

Yes, this means don't let BUBBA do wiring for you. And, if you are not the first owner, remove the screws holding the engine instruments and make sure that BUBBA was not the first owner and did all his own wiring!

Re: Lost Rudder/Post Corrosion - Mainsheet Article

Posted: Fri Mar 13, 2020 2:23 pm
by Eludin
I am the author of this article. I have been sailing all my life and have owned keel boats since 2001 (first a C 30 and later the C 350). I also have a master captain's license. Notwithstanding my experience and training, I NEVER KNEW that something like this could happen. It was a shock to lose my rudder. Loose wires can be broken which can cause a device to stop working. But, I never imagined it could do this type of damage. The risk of damage by stray 12 volt DC really needs to be taught in any class relating to electricity on a boat.

We all seem to have this feeling that there is some kind of "black magic" when it comes to corrosion caused by electrical current, be it stray electrical discharge or galvanic corrosion. But, I now feel it is something that we need to get our head around. As upset as I am having had this experience, I know it made me a better sailor.

By the way, insurance ended up paying for everything! Thank goodness!