[Amel Yacht Owners] Re: electrolysis on mast/boom connection


Danny and Yvonne SIMMS
 

Hi Paul, thanks for this.. Do you think the potential will remain low after turning? or will it go back up again. I found 0.5 volt potential between the vertical bolt and the alloy block it goes through.(it has been as high as 0.7) I removed them and found still the 0.5 volt between the vertical bolt and the block while they were totally isolated from any thing else. There has never been potential between the horizontal bolt and anything else. After sitting on my bench overnight the differential was 0.2. I have just been experimenting and found moving the bolt changed the volts. The bolt is the positive.
It was interesting that the voltage remained when the block and bolt were totally isolated.
The question is whether this is what is causing the electrolysis on the plate on the mast. The same potential exists between the vertical bolt and the mast. The next question...what to do about it?
Regards
Danny
SM 299 Ocean Pearl 



From: "osterberg.paul.l@... [amelyachtowners]"
To: amelyachtowners@...
Sent: Friday, 15 January 2016 3:48 AM
Subject: [Amel Yacht Owners] Re: electrolysis on mast/boom connection

 
Danny
After turning the vertical bolt holding the boom a few turns the potential difference went down from 0,4 V to 5 mV, I will try to remove the bolt and apply Tef-Tec to it, but it's rather hard work to turn it, but 5 mV much better than 400 mV. I also notice some potential difference (5-20 mV) between the smal screws holding the "folded cover" for the slot in the mast, Can be worth measuring other areas where SS and aluminum are bonded together
Paul SY Kerpa SM#259 



Paul Osterberg
 

I will try to remove the bolt and clean out eventual crust or what ever I will find, then apply some Tef-Tec, I hope that will solve the issue. If that not work i will, I consider to put a ground wire to the bolt, and or put a zink anod on the mast.
Paul SY Kerpa SM#259 




Danny and Yvonne SIMMS
 

Hi Paul. I connected with grub screws and wire all of the boom, bolts, block and mast. Didn't seem to help.  I considered grounding it, ie connecting it to the boats grounding circuit system that is linked to the rudder zinks but was unsure about poking  that much current into the system. But the Zink on the mast, sounds good. Would it work? guess it should. Why don't I think of simple solutions like that.
I have had recommended a product called duralac to use between and stainless/alloy contact points. I too have a voltage between the small screws on the mast and the mast but no or very little corrosion around those points.
Thanks
Danny
 



From: "osterberg.paul.l@... [amelyachtowners]"
To: amelyachtowners@...
Sent: Friday, 15 January 2016 8:23 AM
Subject: Re: [Amel Yacht Owners] Re: electrolysis on mast/boom connection

 
I will try to remove the bolt and clean out eventual crust or what ever I will find, then apply some Tef-Tec, I hope that will solve the issue. If that not work i will, I consider to put a ground wire to the bolt, and or put a zink anod on the mast.
Paul SY Kerpa SM#259