Hello and welcome to the group;
Sorry to not address you by your name but I did not see your name in the e-mail.
I cannot comment on the source of your particular issue. However if you are connected to shore power in a marina or harbor without a galvanic isolator, you are exposing the boat to a high risk of electrolysis depending on your particular location, wiring and boats surrounding you.
I would highly recommend the installation of a galvanic isolator to prevent creating an unintended electrical circuit. Olivier recommended the install on our 54 during the survey. The installation is fairly straight forward and it took us a couple of hours to get done.
Mohammad and Aty
Amel 54 #099
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Tuesday, January 09, 2018 8:11 PM
Subject: [Amel Yacht Owners] electrolysis on jib furling gearbox? [1 Attachment]
Greetings and Happy New Year,
I’m new to the group having purchased “Liebling” SM hull #207 In June 2017. Now she is “La Querida” berthed in Moss Landing, California.
Over the last several months I noticed something like grease dripping out from the jib furling gearbox and finally dismantled it last weekend. In general it was in reasonable shape for a 20 year old gearbox. However the aluminum disc on the out put shaft showed considerable pitting which I interpret as electrolysis. On my particular box, the aluminum is in contact with a bronze or brass bushing. I did some reading on line and was quite alarmed to learn that neighboring boats and poor grounding of the marina shore power apparently can accelerate electrolysis on a well designed and maintained boat such as our Amels. So two questions:
Thanks in advance.
BTW our plans are to cruise to Mexicos west coast after retirement in about 3 years. Saludos a todas!