Hull protection is a technique used to prevent corrosion and other types of damage to the hulls of ships, boats, and other marine structures. One common method of hull protection is cathodic protection, which involves the application of a direct current (DC) to the hull to inhibit the corrosion process. There are two main types of cathodic protection: sacrificial anode cathodic protection and impressed current cathodic protection.

In sacrificial anode cathodic protection, a metallic anode is attached to the hull and connected to the ship’s electrical system. The anode is designed to corrode more readily than the hull, so it will sacrifice itself to protect the hull from corrosion. This type of cathodic protection is relatively simple and inexpensive, but the anodes will need to be replaced periodically as they are consumed.

In impressed current cathodic protection, a DC current is applied to the hull using an external power source and inert anodes as carriers of the current. This method is more complex and requires more equipment, but it can provide more consistent and effective protection. Impressed current cathodic protection is often used on larger vessels or in environments where corrosion is a particular concern.