ANODE ACADEMY #4 - Electrolytic Corrosion

ANODE ACADEMY #4 - Electrolytic Corrosion

September 12, 2018

If you’ve been paying attention, now you understand why metals corrode, but wait, there’s more information that can help you take care of your boat. Anodes can and do erode at different rates. One of the most common reasons for an increased rate of erosion is caused by stray current leakage. This leakage is referred to as electrolytic corrosion. Galvanic Corrosion (see ANODE ACADEMY WEEK #3) and Electrolytic Corrosion are often confused with each other, but it is important to know the difference. Here’s how it works and how you can protect your boat.

Electrolytic Corrosion is driven by an external source of electromotive force (EMF). EMF can also be referred to as stray current leakage. This leakage can come from any external power source like your shore power connection, a battery on your boat or the wiring that controls the lights. Stray current leakage typically occurs with a damaged or worn out wiring system or poor installation of electrical equipment. This lack of grounding causes an increased amount of electrical activity which accelerates the rate of corrosion to an anodic metal.

Here are some examples…

#1- If you have twin inboard motors and the shaft anode on the left/port shaft always seems to erode at a faster rate than the one on the right/starboard, you most likely have a wiring issue internally near the left side. It could be a wire connection that has come loose, worn out, or was never grounded properly in the first place.

#2- If you move to a new marina and notice that your anodes are eroding at a faster rate than they did at the old marina, there may be wiring issues with the shore power, or a boat around you may have wiring issues that cause increased electrical activity around your boat.

The bottom line is this, there are numerous factors that can cause damage to your boat, be sure you are using Martyr sacrificial anodes to protect it.

Come back next week to learn which type of anode you should be using for your boating environment.

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