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Posted by on Feb 1, 2013 in Ask the Expert, How To, Maintenance, Powerboating, Sailing | 2 comments

What’s My ZincSaver For?

If you keep your boat at a dock with the shore power cabled plugged in, you should have one of these devices to prevent galvanic corrosion.

Question: Recently I had a chance to look behind the scenes on my new catamaran to get a feel for where things are and what is actually installed. In the photo I sent along, I see this grey box simply called a ZincSaver. What is it anyhow?


The ZincSaver device protects against galvanic corrosion when your boat is plugged into AC shore power.

Answer: A good question and one that we get from time to time. ZincSaver is actually a trademark for a product that has been produced by Professional Mariner for many years. What you have on your boat is the much-improved newest version.

The ZincSaver is what is known as a galvanic isolator. If you keep your boat in a marina plugged into shore power, you really do need this type of device. What people have trouble understanding is that whenever they are plugged in at a dock in a marina, they are actually connected to all of the other boats plugged into the dock via the green “grounding” wire in the dock’s electrical distribution system.

On your boat the green wire is also connected to a part of your boat’s wiring system known as the “bonding” system. This is all part of an electrical network that is supposed to keep all things metallic and in contact with sea water at an equal ground “potential.” The system also serves to support another important safety feature; that is to provide a ground fault path to insure that a circuit breaker trips in the event of an electrical short circuit in an electrical appliance on your boat.

The whole system is also tied to your boat’s anode (zinc) system to provide protection against corrosion of underwater metal fittings on your boat. The problem is that when you are plugged into shore power, without the ZincSaver installed, your boat’s anodes, which may or may not actually be made of zinc (more common today is aluminum alloy) will be helping to protect all the other boats on the dock that may have inadequate corrosion protection via their anode systems. The ZincSaver achieves this by effectively blocking low-level galvanic electrical current flow to and from your boat inside the zinc saver device. The unit will still allow for the passage of any fault current in your boat’s AC shore power system, if that should ever occur, but it will stop the flow of low-level DC current associated with galvanic corrosion.

The bottom line is that if you keep your boat plugged in at a dock, you need one of these devices.

Need zincs? We’ve got ‘em, at the Gear and Parts Store.

- Ed Sherman


  1. my old zinc saver has given the ghost. How do I get one from your country? I reside in durban south africa my boat a searay sundancer 1985 29ft
    luke craft marine

  2. West Marine here in the US does ship internationally. The Promariner units are what you need. You can check them out at They also have and international department. The tel# is: 831-761-4800