The paper has two basic parts. The first describes the maintenance-free performance and economies that can be realized through the use of copper-nickel alloys in the salt water environment. The data presented has been obtained in studies of the performance of a copper-nickel hulled fishing vessel during two and one-half years of operation. Comparisons are made with the performance of steel-hulled sister ships. Significant savings result from the antifouling and corrosion resisting characteristics of the material. Observations of performance of dissimilar metal combinations in seawater are reported.
In the second part, methods of construction with copper-nickel plate and copper-nickel clad steels are discussed. Details reported are attachment of 8' × 15' × 1/4" copper-nickel plates to a steel framing and procedures for all position field welding using. 65 Ni-35 Cu and 70 Cu-30 Ni stick electrodes.
The antifouling properties of copper have long been utilized in coatings for marine applications. However, it is possible to have all the advantages of the best copper coating without the disadvantages of periodic maintenance, under film corrosion and diminishing performance. Copper Alloy No. 706 (88.6% copper, 10% nickel, 1.4% iron) offers excellent antifouling properties, resistance to erosion and corrosion in seawater, good weldability, and useful strength. Almost as important as a practical consideration, the alloy, as a solid material or clad on steel, can be joined to steel and incorporated into existing designs with very little modification. To demonstrate this concept the Copper Mariner, a 67-foot shrimp trawler, was constructed with a Copper Alloy No. 706 hull as a working prototype. The hull of the Mariner and many items of hardware were made by welding 1/4-inch plate of the copper-nickel alloy. The vessel has clearly demonstrated that antifouling and maintenance-free systems are possible.
The Copper Mariner was built to establish by actual performance that the inherently anti-fouling and corrosion resistant Copper Alloy No. 706 was an economical and structurally sound choice for service in seawater. The alloy was used for the hull plates from keel to gunwales. Construction of the vessel was a cooperative effort of Copper Development Association Inc., Artilleries IMESA, S.A., a Mexican builder of commercial fishing vessels; The International Nickel Co., and Booth Fisheries, a division of Consolidated Foods, Inc., Chicago, the vessel's owner and operator.
Factors contributing to the savings which it was felt should result from use of copper-nickel as a hull material are:
Reduced fuel bills,
no corrosive deterioration of the hull material,
no expenses for periodic haulout, scraping and painting of the hull, and
more time at sea.
Performance and operating costs of the Copper Mariner have for three years been compared to sister ships launched at the same time, working out of the same port in the same type of service, and built to identical specifications except for the hull material.
Construction of the Copper Mariner is according to American Bureau of Shipping rules. The vessel is fully classified by American Bureau of Shipping with "Maltese Cross Al Fishing Service."