Fouling, ship hulls

Fouling of hulls leads to a significant increase in the surface roughness which in turn Introduces an economic penalty for ship owners. The Importance of surface roughness has been reviewed by Christie (J ), who also describes the development of self polishing... 

Protective Coatings. A variety of protective coatings is available for steel in sea-water service. For such applications as ships hulls, normal practice is to apply compatible antifouling paint over the corrosion-resistant primer coating system. Figure 4 shows panels which have resisted fouling for a year or more as compared with adjacent panels where the experimental coating is not protective. 

The present-day Black Sea, similar to many other seas, is an area of practical human activity. Changes in the composition of flora and fauna are caused by the unintentional delivery of new species with ships, by intentional introduction of commercial species and unintentional release of other species with them, by insertion by aquarium holders, and by the propagation and spreading of species over newly constructed canal systems that connect previously isolated basins. At present, among the above-listed ways (vectors) of penetration of accidental invaders, the principal ways are the transfer with the ballast ship waters and traveling with the fouling communities of ship hulls. 

The invasion of alien species via the three pathways mentioned is mainly implemented with ballast waters of ships or with the ship hull fouling communities. 

Tributyltin (TBT) is used as an anti-fouling compound to prevent the growth of microbes and fungi, and to prevent the attachment of barnacles and other organisms to ships hulls. TBT has been found toxic towards aquatic organisms, including fish and marine mammals, rapidly accumulating in them [296]. 

Callow [1990] has described the use of antifouling paints in conjunction with ships hulls to reduce microbial and macro-fouling, but the principle could be applied to heat exchangers in suitable environments. She defines three major types of antifouling paints. 

Although trace amounts of copper are essential for life, copper in large amounts is quite toxic copper salts are used to kill bacteria, fungi, and algae. For example, paints containing copper are used on ship hulls to prevent fouling by marine organisms. 

For ship owners, the fouling of the ship hull has many detrimental effects. Both soft and hard fouling leads to increased drag on the ship which decreases both the speed and fuel efficiency of the vessel, and consequently leads to an increase in operating expenses (1). It has been reported that for oceangoing freighters, a 20% increase in fuel costs, or 1 MM per year could be anticipated (2). 

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