Zinc Anode Question

[ak-guy]

What is a Taiwan zinc? In searching for a plate zinc with 3" center to center bolt spacing the only one I could come up with has a galvanized steel core. This seems odd to me. It is also refereed to as a Taiwan zinc. I have a fiberglass hull.

 

[AKDoug]

The plate zincs have a steel core so it doesn't fall off as the zinc erodes, otherwise the zinc might lose it's material around the attachment bolts and just fall off leaving you unprotected. I am unfamiliar with the term Taiwan zinc...

 

[psneeld]

Also I believe the bolt spacing and slot size is different from moant regular sized zinc.

 

[Capecodder]

Good information on this site BoatZincs.com (978-841-9978) - FAQs

 

[HopCar]

You could use a “Diver’s Zinc”. They have slots instead of holes so they fit a wide range of bolt spacing.

 

[psneeld]

I use Mini Divers, but the threaded rod is thicker than the slots by a 1/4 inch or so....weird Taiwan threaded rod used throughout the boat.


nothing a drill doesn't fix.

 

[foggysail]

Just my humble comment, you are better with aluminum than zinc for two reason. First, aluminum has greater amp hours/pound than zinc. Second, aluminum is less expensive.

I use a so called diver's plate anode 6X12X1 mounted on the stern. That one anode protects all of my underwater metals and lasts our New England boating season.

 

[ak-guy]

Just my humble comment, you are better with aluminum than zinc for two reason. First, aluminum has greater amp hours/pound than zinc. Second, aluminum is less expensive.

I use a so called diver's plate anode 6X12X1 mounted on the stern. That one anode protects all of my underwater metals and lasts our New England boating season.

I was ready to buy aluminum instead of zinc for the reasons you stated. Then I learned that aluminum wasn't good on a boat that wasn't used a lot. Aluminum is great on for example a commercial vessel that is used daily but not on a yacht that is used occasionally. Here is one exampple:
https://citimarinestore.com/citiguide/when-to-use-zinc-anodes-over-aluminum-anodes-on-a-boat/

 

[foggysail]

I was ready to buy aluminum instead of zinc for the reasons you stated. Then I learned that aluminum wasn't good on a boat that wasn't used a lot. Aluminum is great on for example a commercial vessel that is used daily but not on a yacht that is used occasionally. Here is one exampple:
https://citimarinestore.com/citiguide/when-to-use-zinc-anodes-over-aluminum-anodes-on-a-boat/

I have a problem with some of the assumptions made in your attached URL. One is that magnesium will not work in sea water. Here I would suggest that a better statement would be magnesium is unsuitable for sea water use. Yes, it will provide excellent protection but not for long. The metal’s higher voltage will result in higher ion flow and quickly destroy the metal. I also do not believe it has a very high amp hour rating/pound or at least not as high as aluminum.

That higher self voltage is ideal for fresh water usage where the water’s resistance is much higher than sea water. Now back to aluminum for boats that see a few trips during a season. The ocean water’s resistance is not going to change very much for a boat moving vs a stationary boat. If anything, I believe a moving boat could have a higher resistance between the metals caused by a disturbance in the ion flow. I yield to others here who may have expert knowledge pertaining to ion flow in a conductive medium.

Our boat most definitely spends far greater hours docked than in motion. My aluminum anode experience indicates that the anode provides excellent protection. I did however have to increase the anode’s mass in order for the anode to perform as needed near the season’s end. I was using a 6x12x0.5 diver’s plate and I doubled the size to 6x12x1....inches of course.

I can get by with one anode only because I made and installed bonding brushes for the boat’s prop shafts. I periodically measure the anode’s performance using my silver-silver chloride half cell. When my measurements begin to fall from 0.8 absolute volts it indicates anode trouble.

So I guess it matters not what you anode material you selected to provide galvanic corrosion protection for your boat as long as you remain protected. With that, I am very pleased at how well aluminum has performed for me over the last ten or so years.

 

[fstbttms]

What is a Taiwan zinc? In searching for a plate zinc with 3" center to center bolt spacing the only one I could come up with has a galvanized steel core. This seems odd to me. It is also refereed to as a Taiwan zinc. I have a fiberglass hull.

This is what you are looking for. Model number ZHC-2. Also known as a "Taiwan predrilled anode":