SHIPS' CATHODIC PROTECTION SYSTEM
ZINC & ALUMINIUM HULL & TANK ANODES
Corrosion causes frictional drag on the ship's hull which in turn leads to higher operating cost. A high quality Coating provides a smooth hull and together with a well-engineered cathodic protection system, helps to ensure That the surface is maintained in good condition.

Sacrificial anode systems are commonly used for external Hull cathodic protection as they are virtually maintenance Free. Anodes for the external hull are designed to protect localAreas and are evenly spread to ensure a good distributionOf current.

Anodes located in the stern area are normally spaced Closer together becaus turbulence in this area increases Oxygen content in the water making it more corrosive and hence a higher current density is required to provide Cathodic protection.

Cathodic protection of ships' cargo and ballast tanks is effected using sacrificial anodes. Zinc and/or aluminium Anodes are used and the material selection depends on the Compatibility of the alloy with the service of the tank. Aluminium anodes are acceptable in cargo/ballast tanks Provided they are not located at a height (in metres) greater Than '27/W' where W is the total mass of anode and core (in Kg).

Zinc presents no spark hazard and thus zinc anodes are Commonly used throughout. Magnesium anodes present a Spark hazard and are not allowed, except as ribbon for descaling. Aluminium anodes as well as zinc anodes conforming to US Military Specification 18001K.