SNAME San Diego Section Hears Paper On Sheathing Hulls With Copper-Nickel

The San Diego Section of The Society of Naval Architects and Marine Engineers gathered recently at the Harbor House to hear a paper by D.W. Czimmek and L.W. Sandor titled, "Economic and Technical Feasibility of Copper-Nickel Sheathing of Ship Hulls." Mr. Czimmek is a research project engineer at Newport News Shipbuilding and Dry Dock Company in Virginia; Dr. Sandor is manager of materials technology at the Franklin Research Center in Philadelphia. Both authors are members of the SNAME Technical and Research Panel HS-9. In 1979, this panel became interested in copper-nickel sheathing as a biofouling protection of ship hulls.

Mr. Czimmek investigated the economic feasibility of copper-nickel sheathing for two ship types on a life-evcle basis. The ship types chosen were an 18,000-dwt RO RO vessel and a 280,000-dwt tanker. Three different antifouling systems were traded off in his studies— conventional antifouling paint, self-polishing copolymer (SPC), and copper-nickel sheathing.

Dr. Sandor addressed the technical feasibility of copper-nickel sheathing. Four methods of attachment were discussed. Test results were presented of the in-service performance over a period of two years for four groups of sheathing panels attached by the various methods to the 90,000-dwt tanker Arco Texas. New, cost-effective welding techniques for copper- nickel sheathing were also introduced.

The results of the analysis indicate that there is an economic advantage to ship operators by sheathing their vessels with copper- nickel. Some of these advantages are: low hull surface friction for the ship's life, resulting in fuel savings, reduced maintenance cost, and reduced drydocking time. Environmental problems due to toxic waste associated with the removal of conventional antifouling paint and SPC during recoating of ship hulls are eliminated as well.

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