ELECTRICITY, ELECTROLYSIS & GALVANIC CORRISION

[Lobo]

This summer my yacht club completely replaced our 290 slip 50/60+ year old docks with new pilings, docks, power, water lines and fire protection. After power was installed two of our members – Roger, an electrical engineer and Mike – a commercial electrician took up the challenge of checking for stray currents that lead to electrolysis. This led to Roger putting on a 2-hour seminar at a standing room only event this week on electricity,electrolysis and galvanic corrosion. There was a 43 page PowerPoint included in the seminar. I asked Roger if I could lead Tugnut Members to it and he agreed.

The presentation starts off with “what is electricity?” and ends up explaining just what electrolysis and galvanic corrosion are, how it happens, how your neighbours contribute, what to look for, and how to combat it.

The presentation was filmed and at a later date should be on U-Tube, and I will post the link for you. No matter your level of knowledge in this topic – you will find something of importance that you might not have known.

To get the material:

Website: rvyc.bc.ca. This gets you to the home page. On the right hand side click LATEST NEWS, then click ELECTRICITY, ELECTROLYSIS AND GAVANIC CORRISION and then click the blue “here”. Download and save to that special spot on your hard drive for important boat stuff. This will be available on our site for a “short while”.

Check the bottom of page 43 for Rogers qualifications.

Dave
LOBO

 

[nzfisher]

Wow. Looking forward to the YouTube presentation.

 

[knotflying]

Thanks for the information. Definitely a good read while at the dock or anchored out.

 

[Hydraulicjump]

This was great! Thanks so much. Still burning through anodes every other month, even when unplugged from shorepower and with all systems shut down (I know that there are multiple things still drawing juice, like the propane valve and CO detector). I am in a very hot marina I guess.

Our systems are bonded, but I am wondering why there is no sacraficial anode on the transom linked to the bonding system. Or is the prop zinc supposed to cover that? Or worse, have I missed something?

 

[elan]

No you have not missed something, replacing zincs every other month is NOT normal.
As to the external zinc for your grounding system.
For whatever reason(cost) Fluid uses the negative wire on the batteries for grounding? We have installed a large zinc(divers dream) on the transom just below the water along with a galvanic iselater, problems went away!
Make sure that ALL the green grounding wires are sanded clean by taking them off & reattaching them, then spray them with clear lacker to seal them from moister & or corrosion, your prop zinc nut only protects the shaft & prop
Hope this helps to answer your query,
Mike
M/V Elan
2012 CW 26

 

[Hydraulicjump]

Thanks! I have a grouper hanging over the side, which has slowed the anode loss, but it is still way too fast. Time for a galvanic isolator and a transom anode.

 

[dialtone]

I installed a galvanic isolator and still replacing zincs every other month too. I have also removed green wires, sanded, re-attached. My diver says something is still wrong but not as bad as before. Transom anode sounds good and boat is coming out of water for other repairs so good time to do it. Any other advice? I'm going to download the ppt now

 

[bakerboat]

Hi,

Relatively new Tug owner here. I'm kind of surprised there has been no mention of the use of a silver/silver chloride (AG/AgCl) cell to help analyze the excessive zinc usage folks have been experiencing. It's a very useful tool and can tell you if there is voltage/current in the water causing the problem or if you are under or over zinc'd. Boatzincs sells them and has a useful manual they provide. I have one but our R27 is in Georgia for the winter and we're in Maine. It will be one of the first things I check when we get her back in the water in May.

Here's one article on the process:

http://assets.fluke.com/appnotes/electr ... 269b_u.pdf

Regards,
Ken
2013 R27 O' Meara

 

[swordmanjosh]

Thank you for the post. Love the Tugnuts.

 

[macnmm]

https://www.rvyc.bc.ca/images/Club%20Do ... _SMALL.pdf

 

[walldog]

Thanks to Dave and Mac for this most informative discussion about a universal problem. I have downloaded the pdf found at the link and will keep it in my boat files.