isolating a rudder post

gkny

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I have a boat with an aluminum rudder post and a whitlock steering system with a draglink.  There are rod ends on each end of the draglink or rod connecting the pedestal to the rudder quadrant.  I bought some stainless steel replacements that had ptfe races supposedly but the bearing is not electrically isolated from the body.  I am not sure whether the whitlock replacements are isolated.  I have been pretty careful with the electronics at the pedestal but would prefer to have things isolated as well as possible.

The rod ends thread onto the rod.  Would tefgel on the threads and a nylon washer on the locknut that locks the rod bearing work?  I am not worried about corrosion of the rod but a galvanic effect on the rudder post.  I know that I can measure for continuity but I am not sure how reliable such an approach would be over time. 

 

DDW

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Tefgel will not help. I have used generic SS rod ends in my drag link on Jefa equipment, the rod end definitely isolates. They were sourced from McMaster, manufacturer unknown. If the rod ends have proper PTFE bearings there should be no continuity. I believe Jefa rod ends have a plastic ball, so they would definitely insulate. Note that rod ends can rotate, putting the body in contact with the fixing bolt or other hardware, which would produce continuity. If that is what is happening you need an insulating washer to prevent it. 

 

gkny

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I just measured for continuity from the body to the bearing that goes on the post and found that even when it was sitting flat on a table.  The multi-tester indicated continuity.

 

gkny

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I did check on some plastic Igus ones and the strength is quite a bit lower. The problem that I am having is that the conductance of these joints isn't something that is specified

 

slug zitski

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What component of your steering system is causing this electric leak ? 

Is your boat made of metal ?

Typically, on a glass boat  only the autopilot ram is a dc volt leak source 

 

DDW

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I believe the Jefa rod end bodies are hard anodized aluminum, in which case they would insulate even if in contact. 

These are the ones I used. McMaster will let you return anything for any reason without an RMA. They are available in metric also if that is what you have. You could order one, test it, and return it if it did not isolate. 

 
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