Many antifouling treatments are available including paints, the best of which all include a proportion
of copper which is slowly released as a biocide. Naturally, such coatings have a finite life and can
only extend the periods between dry docking rather than avoid the need for them.
While the fouling resistance of the copper-nickel alloys has been known for years, their use has been
restricted by their initial cost which is higher than that of steel. Now that the cost of all forms of
energy has risen, the total-life economics of the use of fouling resistant alloys has become more
attractive. Fuel savings and elimination of the loss of revenue during dry docking can now give
payback periods as short as 3½ years.
During the construction and operation of various types of hulls, the best techniques of construction
have been evaluated as well as the operating costs. With the techniques of joining these alloys
autogenously and to other metals such as steel now well established, the expansion of this market is
continuing.