CORROSION COMMENTARY Available to Purchase

NEW ANTI‐FOULING SYSTEM. Localised penetration of anti‐corrosive paint systems on hulls can be caused by fouling organisms; they also encourage the growth of sulphate‐reducing bacteria in slimes which tend to decompose many anti‐corrosive paints. These are only two of the effects of fouling. Although less concerned with corrosion than we are in modern times, the Phoenicians in 800 B.C. were aware of some of the other effects of fouling and used copper sheathing as an anti‐fouling measure. Similarity between the principles and materials employed then and those in use today is outstanding, for copper remains the most widely used toxic included in anti‐fouling paints. There was one period in naval history, however, when the use of copper had unfortunate results. This was in the late 19th century with the introduction of iron ships. The practice of fitting copper sheathing was carried over to iron hulls; the iron hull was immediately rendered anodic to the copper and considerable corrosion ensued, while the copper, being the cathode, failed to pass into solution and therefore its toxic qualities were lost and fouling continued unabated. The fouling problem influenced the British Admiralty towards discontinuing the use of iron ships.