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Corrosion and biofouling of shipboard seawater piping and cooling systems reduce readiness, impact operations and are costly to prevent and to remediate (Jones and Little, 1990). The materials most widely used currently by the Navy in these systems are copper-nickel alloys, which are susceptible to erosion corrosion and microbiologically influenced corrosion (Little et al., 1990; Little et al., 1991). Titanium has been proposed for more extensive use by the Navy in seawater piping and heat exchanger applications because of its high corrosion resistance, high strength, and light weight. Titanium is susceptible to biofouling, however, and currently used chemical fouling control methods, such as chlorination, may soon be phased out due to their adverse environmental impact. Alternative biofouling control technologies are available, and new technologies currently are under development. Ultraviolet (UV)sterilization and ozone disinfection are two technologies that have been used successfully to maintain control of microbial populations in a wide variety of both freshwater and seawater applications. Ozone has the added advantage of removing dissolved and suspended organics, color and odor from the water. Both ozonation and ultraviolet irradiation are non-polluting and are economically competitive with chlorination for water treatment when the expense is considered of dechlorination chemicals and injection equipment that are necessary in order to meet strict government regulations for effluents. We have been testing the effectiveness of several potential alternative methods to chlorination for environmentally safe control of biofouling in seawater piping. NSWC/Code R33 has a titanium test loop at Ft. Lauderdale, Florida.