MG Duff MD72 Straight Magnesium Hull Anode for Fresh Waters (4.5kg)

Part No: AA-072

MGDUFF MD72 straight shaped magnesium sacrificial hull anode, suitable for use in fresh waters. Sacrificial anodes should be fitted and correctly bonded to all boats / vessels to help prevent corrosion by cathodic protection when in the water.

Wooden hulled vessels operating in fresh water are subject to the same corrosion problems as GRP craft. However the fitting of magnesium anodes is NOT recommended as they will have a damaging effect on the timbers around the fixings known as electro-chemical decay. MGDUFF advise that the appropriate action is to fit a magnesium shaft collar on the exposed propeller shaft and if necessary to fit anodes directly to mild steel rudders and keels.

Cathodic protection is an electrochemical process which halts the natural reaction (corrosion) of metals in a particular environment by superimposing an electrochemical cell more powerful than the corrosion cell. Sacrificial anodes are fitted or bonded to the metal to be protected which in turn, as it has a greater electrical potential than the anode material, becomes cathodic and causes the anode to waste instead of itself.

All cathodic protection systems must be inspected annually and the sacrificial anodes renewed if more than 50% are wasted. You should check the working surface of the sacrificial anode to ensure that it is free of paint and chalky corrosion deposits. When fitting or replacing a sacrificial anode you should also replace the serrated fan disc washers under the nuts and change the anode backing sheet on wood and GRP hulls. Exposed fixing studs, nuts and washers should be well greased or painted after assembly.