Re: [Amel Yacht Owners] electrolysis on jib furling gearbox? [1 Attachment]

John Clark

Is it possible that this is localized galvanic corrosion caused by saltwater/salt accumulation under the disc?  Two metals+saltwater.....

SV Annie SM37
St. Augustine.

On Jan 9, 2018 11:11 PM, "pandmdegroot@... [amelyachtowners]" <amelyachtowners@...> wrote:
[Attachment(s) from pandmdegroot@... included below]

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:

  1. Has anyone else experienced this electrolysis on the aluminum disc on top of the gearbox?  (or is mine indicative of a bigger problem)
  2. I briefly investigated galvanic isolators as protection for poorly grounded shore power.  Is this worthwhile?

Thanks in advance.

BTW our plans are to cruise to Mexicos west coast after retirement in about 3 years.  Saludos a todas!

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