CORROSION ON DEEP GULF SHIPWRECKS OF WORLD WAR II1

摘要

During the summer of 2004, National Oceanic and Atmospheric Administration's (NOAA) National Marine Sanctuary Program (NMSP) participated with Minerals Management Service (MMS), NOAA's Office of Ocean Exploration (NOAA OE) and C&C Technologies, under the auspices of the National Oceanographic Partnership Program (NOPP), in an investigation to study the "artificial reef effect" of manmade structures in differing depths, and conversely, the effect of the environment on those structures over the course of 60 years, by studying six steel-hulled vessels sunk in the Gulf of Mexico.The National Marine Sanctuary used this opportunity to con- duct research on the effects of corrosion on the six vessels identi- fied for study. Corrosion on Deep Gulf Shipwrecks of World War II project represents Phase II of NOAA's RUST database project. Through this study, we addressed the following questions:1 Does depth of a wreck effect state of corrosion?2 Is this primarily a chemical, physical or biological process?3 Do ferrous-hulled shipwrecks follow a fairly consistent degradation process as they age?4 Is it possible to attach a specific timeline to the degradation scale?The corrosion processes affecting the structural integrity of these vessels is important for two reasons. If we begin to gain an understanding on the corrosive processes at work, we may be able to develop an approximate time line on the eventual fate of these vessels. Second, applying this corrosion timeline, it may enable us to anticipate when tanks and holds containing fuel oils or other hazardous materials will fail and release their cargos into the en- vironment. Using this information, resource protection personnel can assess sites and determine which vessels are considered for direct intervention such as the removal of the threat sources, iso- lation of the threat, and management plan development or estab- lishment of a monitoring protocol for the site. The survey has added valuable assessment data on steel-hulled vessels and contributes to our understanding of both chemical and biological corrosion in the marine environment. The survey also contributes to the field of underwater research, allowing inter- pretation and peer review of the results, provides baseline data to examine long-term protection strategies for National Marine Sanctuaries currently threatened by shipwrecks containing oil within or in close proximity to their boundaries.