Impressed current cathodic protection systems (ICCP) predominate in ships today, especially when current needs and electrolyte resistivity are high. They can be automatically controlled when a ship is operating in varying conditions. The necessary protection current is automatically adjusted for changes in ship speeds and electrolyte resistivity (as when a ship enters brackish or fresh water) so that the ship is neither under protected nor overprotected. Unlike galvanic anode systems where the natural potential difference between the anode and cathode provides the driving force for current, an ICCP system is supplied with power from an external source. The power supply converts shipboard AC power to low-voltage DC and allows an adjustment of electrical current delivered to the anodes.