Copper bottom sticks to its task

Growth of marine organisms on ship hulls and structures has been a problem ever since men first went to sea

Problem: . It causes unwanted excess drag on marine craft and structures as well as blockages in pipe systems. Regular removal requires expensive mechanical means, such as by divers using high pressure hoses, or dry docking and scraping. Biocidal organo tin coatings to prevent marine growth are in the process of being banned because of their bad effects on the marine environment. Solution: The Copper Development Association, at a recent Midland's seminar, mention to Eureka that a solution is at hand. Stemming from an eighteenth century discovery, that naval vessels could maintain performance if their hulls were sheathed in copper sheets, Walsall-based Ecosea has created stick-on sheets of 5mm square, 150 micron thick, copper nickel flakes. Jim Kelly, chairman of Ecosea, and keen amateur yachtsman, conceived the idea for his new product, Cupro FF, after sheathing his rudder with the 90-10 copper nickel alloy. After ten years, it was still clean. This is due to the fact that corrosion rates for copper nickel are lower than for straight copper. The flakes are aligned by an insulating, waterproof, acrylic adhesive membrane. The surface to be exposed to the water has a protective cover that is removed when the hull is completely sheathed. The narrow areas between the flakes are then filled with an epoxy grout prior to launching. Lives in excess of 20 years are predicted and, for fibreglass hulls, the product has the added advantage of preventing osmosis. The material requires only a roller action at moderate temperatures to apply, and can be used for new builds or retrofit. Applications: A derivation of the product can also be integrated into the moulding of new hulls. Leaching trials carried out by CEFAS Laboratories to ISO/DIS 15181-02 have identified low copper leaching rates. Ecosea received a DTI SMART Award in 2001. TS Copper Development Association