A galvanic (also called sacrificial) anode is a metal that has a more negative potential with respect to the structure metal to be protected. Galvanic anodes corrode preferentially to the protected structure, providing protection to the structure. The objective of a galvanic anode system is to deliver sufficient current to protect part of the structure for the designed life of the system. There are three basic components of a marine galvanic anode cathodic protection system.