Sacrificial anodes

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Revised by Hans Karlsson, Corrosion engineer with 30 years of experience within the cathodic protection industry .

Whenever you have two distinct metals that are physically or electrically associated and submerged in seawater, they turn into a battery. A small amount of current streams between the two metals.

The electrons that make up that current and flow are provided by one of the metals surrendering bits of itself- as metal particles – to the seawater. This is called galvanic corrosion and, left unchecked, it rapidly decimates submerged metals.

The most well-known loss to galvanic corrosion is a bronze or aluminum propeller on a stainless steel shaft, however metal struts, rudders, rudder fittings, outboards, and stern drives are likewise in danger. The way we check galvanic corrosion is to include a third metal into the circuit, one that is less noble than the other two to surrender its electrons.

This bit of metal is known as a sacrificial anode, and frequently it is zinc ( usually in brackish waters/seawater ) , aluminum ( usually seawater/brackish water ) or magnesium ( usally brackish water or freshwater ) .

It is difficult to exaggerate the significance of keeping up the anodes on your vessel. At the point when an anode is missing or to a great extent squandered away, the metal segment it was introduced to secure starts to break up – guranteed.

Go to Zinc anodes, Magnesium anodes, Aluminum anodes