Shaft Anodes

Zinc Shaft Anode

Shaft anodes are mounted on the shafts of small leisure vessels to protect the exposed steel prolonging the life of the shafts and propellers. Zinc is the only material that has an official specification, the American MIL-A-18001 K spec. Zinc is a well-proven anode material and its capacity is virtually unaffected by the operating current density, although the driving voltage diminishes with increasing temperature therefore it has limited application. If zinc is not to this specification i.e. commercial purity zinc, it will have a limited use as an anode material because of excessive polarisation due to iron present as an impurity.

Aluminium Shaft Anode

Aluminium alloy anodes are now mostly preferred due to their higher electrochemical efficiency which enables them to operate at different temperature co-efficient. The anodes are less dense than zinc making them lighter and easier for handling when fitting.

Magnesium Shaft Anode

Magnesium alloy anodes are very active electrochemically, and they are usually recommended only for short exposes or temporary protection and in positions where replacement is easy in seawater. Magnesium alloy anodes are often used for hull protection of fresh water vessels i.e. narrow boats/barges.

MCPS LTD manufacture Zinc, Aluminium and Magnesium Shaft Anodes for use with small leisure craft.