Boater’s Guide to Corrosion Prevention

If you have ever consulted a boat maintenance guide, you will have noticed that many of the tasks involved in regular upkeep are intended to prevent corrosion. This is perhaps the most important aspect of boat maintenance, because damage caused by corrosion can be permanent. Corrosion can take hold easily and spread quickly, leading to expensive repairs. 

But what exactly is corrosion, and how does it occur? When you understand the science of corrosion, you will be better prepared to manage it. This article from White’s Marine Center aims to answer all your questions about corrosion.

White’s Marine Center is your trusted boat dealer in Pittsburg, MO. We welcome customers from Kansas City and Springfield, MO.

What Is Corrosion?

Corrosion is a natural process by which metal deteriorates as the result of a chemical reaction with its environment. There are several types of corrosion, but as a boat owner, you should be most concerned about galvanic corrosion.

Galvanic corrosion occurs when two materials with a dissimilar atomic makeup (such as those found in the metal alloys used in boat construction) are brought into electrical contact under water. This activates the positive and negative charge in the materials, and creates a sort of battery. The positively charged metal functions as the cathode, while the negatively charged metal functions as the anode. The cathode attracts electrons from the anode, causing the negatively charged metal to lose particles. This results in the anode breaking down.

It is important to understand the distinction between galvanic corrosion and simple oxidation. While oxidation can cause gradual corrosion over a period of decades, galvanic corrosion happens much faster. That’s why constant maintenance is necessary to prevent galvanic corrosion from taking hold.

Where Does Corrosion Occur?

Galvanic corrosion primarily occurs in areas where steel and bronze or steel and aluminum alloys are in contact with saltwater. The hull, the propeller, and the mast are the most common targets for galvanic corrosion. When working to prevent corrosion, you should focus primarily on these components.

How Do I Prevent Corrosion?

Galvanic corrosion cannot be entirely prevented. This is a natural, chemical process, after all. But you can control where galvanic corrosion takes place. The best approach involves what is called a “sacrificial anode.” This is an easily corroded metal that serves to draw galvanic corrosion away from essential components, like the propeller and the hull.

There are several options for sacrificial anodes, with aluminum and magnesium being the most effective. Your choice of material will depend on the corrosive potential of your hull, and this can be determined using a multimeter. When you have the voltage reading for the hull, you can use the standards developed by the American Boat and Yacht Council to determine the correct sacrificial anode.

Keep in mind that sacrificial anodes are intended to break down over time, so you will need to replace them eventually.

We hope you found these tips helpful! Need more advice on boat maintenance? Feel free to ask the qualified staff at White’s Marine Center. You can find us in Pittsburg, MO.