Before explaining the importance of zincs, let's talk about galvanic corrosion.
Galvanic corrosion is the deterioration of the anode of a galvanic couple resulting from the flow of ions from the anode to the cathode through an electrolyte. To put this in more simpler terms, when two dissimilar metals or alloys are placed together in an electrolyte, one metal will assume a higher potential than the other. Without getting into a deep explanation of cathodic protection and bonding, let's just look quickly at how stray-current corrosion happens and how it can be avoided.
When dissimilar metals such as in bronze thru-hulls, a stainless shaft and a bronze propeller, in an electrolyte (salt water) are mechanically or electrically bonded, the only metal to corrode will be the least noble (highest in the galvanic series) of the group. The metal most often used in boats for this purpose is zinc. The phenomenon is called cathodic protection, and the zinc masses are called zinc anodes, or "zincs" for short.
Anodes are used to protect buried or submerged metal structures from corrosion. Zinc anodes prevent electrolytic corrosion due to stray currents. This sacrificial metal corrodes away while protecting fittings and gear that are much more costly to replace. They must be checked periodically and replaced about a month before they are completely eaten away.
There are different types of zinc anodes - shaft, engine, keel and rudder, transom, and guppy. The techs at Kompletely Kustom Marine will check each one for you and determine whether they need to be replaced or not. Kompletely Kustom also offers dive services for the inspection and/or replacing of your zincs while your boat remains in the water. You can have the peace of mind of knowing that your important metal components are protected without having the expense of hauling your boat out of the water.
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