Galvanic Isolator

[Jim Price]

Friend of mine is a surveyor here in the Southeast and just returned from "corrosion school".  He has an older Allied Princess 36 he is rebuilding for offshore.  Intersting info about corrosion and zincs.

"Just back from Jacksonville where I took a metal corrosion course.  It was quite informative & required studying 4-5 hours every day after class.  Won't know if I passed the certification test for a couple of weeks.  It was an intense course with a lot of information. 

We usually only think of corrosion in salt water, but there is a lot of "stray current" corrosion in fresh water.  Float switches and bilge pumps are a major source of stray current as are heat & AC pumps.  The brushes are carbon & the dust accumulates around the SS shaft then they leak DC current into the bilge water and through the ground wires. 

Also, the zinc anodes are worthless in fresh water.  They "go to sleep".  Aluminum is the answer, it's lighter, more active and lasts longer.  It can also be used in salt water.   NEVER use magnesium as it is so active it will cause the paint to bubble & peal off the boat.  It also should not be used unless the water is free from polutants.  The PH needs to be about 7 for them to work properly.  I have seen so many zincs during my surveys and never realized they were worthless on the lake. 

It has convinced me to install a galvanic isolator on our boat & put all new bonding wires on the metal fittings.  A perfect time since we are in the tear it apart stage & can access everything.  Check out the galvanic isolator that was recommended in the class.

http://www.dairyland.com/index.php?page=products_mgi  "


Just thought I would share his opinion and insight.

[Rick Johnson]

OK, now you have me worried.  Since I'm now in freshwater I took your advice very seriously, but are you sure about aluminum anodes and where do you find them? 

[Jim Price]

I may not see my friend for couple of weeks but I will try to get more information from him about this.  I am certainly not knowledgeable in this area.  He is a certified / registered  :thinksurveyor and is getting additional certifications in electrical and "corrosion"  and I don't know what all else.

This is the first I heard about this so I have interest also.  He just sent me a short email giving the info I quoted.  He is doing some teak work on our boat when the weather is good so I am sure I sill get more info when I run into him.

I just thought I would put this out for folks to mull over.   

[karista]

Interesting information, I will install a galvanic isolator shortly. Does anyone have any experience with the YANDINA Isolator carried by Defender for a very reasonable price?

[BillG]

Check out their website at www.yandina.com for alot of useful info and downloading of the manuals.