Corrosion of a ship’s hull is the biggest fear that a shipowner has because it takes a toll on the vessel’s life, heavily. Hull protection methods are adopted in order to eradicate these complications. Impressed current cathodic protection (ICCP) is one such hull protection method that is highly effective and widely popular. Before learning about Ship’s ICCP, let us see why corrosion takes place in the first place.
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Why is Hull Corroded?
Corrosion is a natural process by which a material, usually metals attain lower energy levels. It is a spontaneous process in which the metal reacts with the environment. In most of the marine constructions, Mild Steel is used because of the ease of operation, strength, and cost factors but mild steel is highly reactive with salt water which facilitates corrosion, and the hull is damaged.
ICCP is a contemporary hull protection method but before it became popular and still today a more reactive material is placed on the hull. It is called a sacrificial anode. Just like how a true leader sacrifices himself/herself to save his/her team, the anode also sacrifices itself to save the hull. The material to be used as the sacrificial anode is decided by referring to the reactivity table of the material with respect to the seawater.
Impressed current cathodic protection (ICCP) System
Because of the reactivity of the hull’s material, corrosion takes place at the hull in which the surface of hull exposed to sea water becomes the anode and is depleted. The result is a corrosion current. The current supplied to the hull to counter the corrosion current is called the ICCP current. Corrosion current is measured by the the reference cell and signal is fed to the vessel ICCP Power supply unit which then sends a current equal to or greater than the corrosion current to the anode. This saves the hull from corrosion and by such simple arrangements we can save millions of dollars.