Zinc anodes, also called “sacrificial anodes”, protect all metal parts below the waterline from corrosion. To prevent corrosion of the hull, the anode oxidises faster than the metal it is protecting, sacrificing itself before the other metal reacts with the electrolytes. The water, which acts as an electrolyte here, varies in its aggressiveness depending on the navigable waters. Typically anodes have to be replaced once per season. In harsh water conditions, a more frequent replacement schedule might be necessary. Anodes are mounted along the keel. The electric current is higher at the stern post due to the propeller being located there. It is advisable to install several anodes in this area. Anodes should also be mounted on the rudder and propeller shaft. For vessels that are predominantly operated in fresh water, we recommend aluminium anodes because aluminium has a relatively high driving voltage compared with zinc.
