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Updated: Dec 12, 2018

Marine Corrosion Resistance, Prevention and Control

No Marine Engine can escape the damage from Marine Corrosion. In it’s simplest form is really a pretty basic phenomenon; Simply put, marine corrosion is an electrochemical reaction that happens when electrons flow between metals that are connected or grounded through water. What does this matter to you? Marine corrosion is the defining factor with regards to the longevity of your boat engine, boat exhaust system and sterndrive. As it happens, this electrical action causes one of the two metals to literally be eaten away – marine corrosion. The process is greatly accelerated in salt, brackish waters, or in waters with a high mineral content. That’s marine corrosion in a nutshell.


There are four essential elements necessary to accommodate marine corrosion. The first of which is the ANODE. The anode is the material that actually gives itself up as marine corrosion takes place. You may have noticed people with zinc anodes mounted on the stainless steel trim tabs on their boats. In many cases, people think Zinc is always the best material to use for an anode. This is not necessarily true. The materials must be matched with regards to the potential between the anode AND the cathode. Zinc makes a very good anode when coupled with aluminum, however in the case of stainless steel a piece of standard angle iron is a much better option. The reason for this is that the potential between stainless steel and zinc is so great that the zinc actually sacrifices itself too fast and will actually create a problem.

The second element of marine corrosion is the CATHODE. The cathode is generally the factor that