Zinc anodes, also called "sacrificial anodes," protect all of the metal parts located underneath the water line (hull) from corrosion. In order to protect the boat's hull from corrosion, the hull is connected to a more inferior metal (anodes), which are oxidized more easily. For example: A zinc anode is attached to a boat with a steel-alloy hull, which causes the inferior metal of the anode (zinc) to sacrifice itself, in order to protect the high-quality metal of the boat's hull from corrosion.
Usually "sacrificial anodes" have to be changed after each season, even more frequently in highly corrosive waters. The anodes are attached along the keel. The current intensity is larger at the hindsteven, due to the position of the propeller. It is advisable to use several anodes. Anodes should also be attached to the rudder blade and propeller shaft. For vessels mainly operated in fresh water, we recommend using aluminum anodes because of the greater potential difference it has to other metals, in comparison to zinc.
This zinc anode has very little resistance in the water due to its flat shape.