What is Corrosion? | What is Cathodic Protection? | What is a Salty Doggs Anode?

Common, but expensive corrosion problem

Did you know, when you are tied into shore power at your marina, your boat’s zinc may be providing current to your neighbor’s unprotected fittings and to the dock grounding system? This will deplete your anodes at a much faster rate and after the anodes are sufficiently depleted, corrosion will start eating away at your stainless steel shaft, rudder, and other metal parts of your boat.

We can solve your galvanic corrosion problems and reduce your zinc replacement costs with a simple, cost effective and proven solution.

Install a Salty Dogg™ I or Salty Dogg™ II anode to take care of current leaks, faulty circuits and to prolong the life of your zincs.

What is Corrosion?
Corrosion is an electrochemical process accompanied by the flow of electrical current. The process of corrosion will take place if the following four components are present:

  1. An electrolyte – a medium which conducts current by ion flow (i.e. water)
  2. An anode – a metal which corrodes to protect another metal (i.e. prop shaft, rudder, hull, etc.
  3. A cathode – a metal which is protected by another metal (i.e. bronze and stainless steel fittings)
  4. A metallic pathway – a medium which conducts current by electron flow (i.e. boat hull, bonding and electrical systems)

Galvanic corrosion is the most common form of corrosion that attacks boats and marine equipment. This type of corrosion develops when different types of metals which are electrically common are submerged into water. For example, when a boat equipped with a steel rudder that is bonded to a bronze or stainless steel fitting is placed into the water, the steel rudder will corrode. In this example, the steel rudder becomes the anode and the more noble metals such as bronze or stainless steel become the cathodes. The water is the electrolyte and the metallic path is the boat’s hull (if metal) or the boat’s bonding system. If this sounds confusing, RELAX!

Corrosion is nothing more than a battery that forms naturally between different types of metals in a boat when the boat is placed into the water. Batteries or corrosion cells also develop between different boats in a marina when they are connected to a common power source on the dock. When this situation occurs, people often refer to the marina as a “Hot Marina.”

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What is Cathodic Protection?
Cathodic protection is the process of reversing the corrosion current to stop the damaging corrosion process. One type of
cathodic protection known as Galvanic Cathodic Protection is achieved by placing a type of metal into the water with the boat, and connecting it to the boat’s metallic parts. Metals such as zinc or aluminum are less noble than the other metals on the boat, and therefore, will act as anodes when connected to the metal parts of the boat. All boats are equipped with zinc anodes that are typically mounted to the hull or prop shaft or rudder, etc. of the boat. These zinc anodes are designed to provide protection from galvanic corrosion on the boat.

However, when these zinc anodes corrode, they lose their ability to provide sufficient protection to the metal parts of the boat that are submerged into the water. Zinc anodes need to be replaced often to keep corrosion at bay. Oftentimes, however, when boat become older and paint on metal parts deteriorates, the zinc anodes are no longer sufficient to provide the degree of protection required. Also, when galvanic corrosion occurs between boats in marinas, the zinc anodes usually are not sufficient to counter this type of corrosion attack as well. A common symptom of these problems is when the zinc anodes on a boat corrode quickly.

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What is a SALTY DOGGS anode?
The SALTY DOGGS anode is designed to counteract the se galvanic corrosion problems by supplementing your boat’s existing cathodic protection system (i.e. zinc anodes). The SALTY DOGGS anode will provide optimum performance and efficiency. The plastic bumpers are designed to protect the hull of the boat from damaging scrapes and dents that would occur of a metal anode were to bang into the hull of the boat due to wave action.

The SALTY DOGGS anode is designed for use on boats with steel, aluminum, and fiberglass hulls.


The current generated by the SALTY DOGGS anode is sufficient to cause alkali damage to the wood in wood hull boats.

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Do you want to learn more?
Please click on the links below to download PDF's with more detailed information.

Installing the Anode

Installing the Anode w/Current Tester

Using the Corrosion-Test-Kit

Using the Reference-Electrode

Using the Shaft-Brush

Still have questions? Please contact us at 1-800-644-6555 or email us at info@saltydoggs.com.