Long-term research on fouling and corrosion has been conducted as a part of the effort to develop heat exchangers for the US Department of Energy's Ocean Energy Technology program. After obtaining initial experimental data from various sites, including Puerto Rico, the Gulf of Mexico, open ocean (a buoy) in Hawaii, and Wrightsville Beach in North Carolina, Argonne National Laboratory carried out a six-year research program at the National Energy Laboratory of Hawaii. In the Phase 1 experimental program, a data base was developed for characterization of biofouling of corrosion-resistant material exposed to two types of seawater -- surface (warm) and deep-ocean (cold). The major objective was to determine optimal biofouling-control methods. The results of the Phase 1 research were published in a report in 1985. The major objective of the Phase 2 research has been to develop a technical data base for the qualification of aluminum alloys for ocean thermal energy conversion (OTEC) heat-exchanger applications. Aluminum alloys have many desirable mechanical properties that can be utilized for the development of low-cost, compact heat exchangers that can be designed on a modular basis. The research program for aluminum alloys has included biofouling, corrosion fouling, uniform corrosion, localized corrosion, and evaluation of brazed joint and epoxy-bonded joints. Conclusions derived in this report represent a major milestone in OTEC materials and fouling research.