2006 Expedition to the USS Macon
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Monterey Bay Aquarium Research Institute's (MBARI) 117-foot water-plane area twin hull (SWATH) R/V Western Flyer served as the research platform for scientists during the USS Macon expedition.
Credit: R. Schwemmer/NOAA |
The overarching goal of the mission was to conduct comprehensive documentation of the USS Macon wreck site that can be used to evaluate the archaeological context of the craft. This will allow NOAA's National Marine Sanctuary Program and the Naval Historical Center to determine the condition of the site, the level of preservation of the archaeological remains, and the potential for research at the site.
Working in collaboration with the Monterey Bay Aquarium Research Institute (MBARI), researchers utilized MBARI's 117-foot (35.66 meter) research vessel Western Flyer, a small waterplane-area twin hull oceanographic ship. The vessel provides a stable platform for deploying, operating, and recovering a tethered remotely operated vehicle (ROV) and capable of working at the required depth of the Macon site.
The ROV Tiburon (retired), deployed from the Western Flyer, has a maximum working depth of 13,123 feet (4000 meters). Tiburon is equipped with adjustable high-definition video cameras and coordinated lighting. A high-resolution video camera system was configured for this mission by Stanford University to be used in conjunction with an ROV control system. The ROV was also equipped with imaging sonar, which was key to maneuvering around the wreck site to avoid entanglement and scan the sea floor for further debris fields.
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Description: MBARI's Remotely Operated Vehicle (ROV) Tiburon being launched into the moonpool on board the R/V Western Flyer. The unmanned submarine is launched and recovered through two folding doors located between the Western Flyer's two hulls. The ROV can dive to 4000 meters (about 2 1/2 miles) depth, and is controlled using a very long cable, which also transmits data and video images back to the ship. The brightly colored upper portion of the ROV is constructed of incompressible foam, whose buoyancy makes the 3 1/2 ton ROV nearly weightless in seawater.
Credit: Greg Pio for MBARI (c) 1997 |
Over the course of a five-day archeological investigation in September 2006, researchers from NOAA's National Marine Sanctuary program, Monterey Bay Aquarium Research Institute (MBARI), University of New Hampshire, and Stanford University conducted deepwater surveys (more than 40 hours of video) using MBARI's remotely operated vehicle Tiburon.
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| Co-Principal Investigators (left to right) Robert Schwemmer (NOAA), Chris Grech (MBARI), and Bruce Terrell (NOAA) examine draft photomosaic. Credit: E. Burton/NOAA |
The first goal of the expedition was to fly the ROV Tiburon above the wreck site and systematically record the visual remains of the airship and aircraft through high-definition video and high-resolution still photography. The imagery will be used to create a photomosaic of the two major debris fields. The photomosaic will provide a visual reference of the full magnitude of the wreck site and assist in the site characterization and interpretation as well as produce imagery for education and outreach efforts.
Researchers documented two major debris fields associated with the submerged wreck site. The two debris fields, designated by scientists as debris fields A and B, are separated by a distance of 250 meters, measure 60 meters in diameter, and are elevated several meters above the seafloor. Several centimeters of sediment were deposited on wreck artifacts, including the wings of the Sparrowhawk biplanes.
The second goal of the expedition was to record in more detail specific artifacts utilizing Tiburon's still camera, video zoom, pan/tilt cameras, and precession parallel laser system for measuring, including examination of the aluminum structural remains of the airship and aircraft. Scientists concluded that sections of the aluminum girder show signs of degradation after 71 years in the marine environment. An analysis will be conducted to compare the 2006 visual record to the site documentation in 1990/91. This may provide important data on the rate of degradation of aluminum in a deep sea, saltwater environment.
Distinguishable features found in debris field A included the airship's hangar bay containing four Sparrowhawk biplanes and their detached landing gear. Five of the Macon's eight German-built Maybach 12 cylinder gasoline engines also were identified. Objects from the ship's galley were found, including two sections of the aluminum stove, propane tanks that supplied fuel for it, and the enlisted men's dining table and bench. Debris field B contained the Macon's bow section including the mooring mast receptacle assembly. This field also contains aluminum chairs and desks that may have been in a port side officers' or meteorologist's office.
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A third goal of the expedition was to conduct a biological survey. Video footage and images from the 1991 survey of the USS Macon indicate the submerged remains serve as an artificial reef in the deep sea. To characterize the habitat and species composition associated with the wreck (and surrounding area), megafaunal invertebrates and fishes were identified using the digital video and still cameras on ROV Tiburon. The biological survey characterized species that occurred on wreck debris (hard substrates) in deep water and will add to the body of knowledge for management and protection of Sanctuary resources.
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| Inverted desk drawers with handles, possibily from the officers' or meteorologist's office located on board the port side of the USS Macon. Splitnose rockfish (Sebastes diploproa) and thornyheads (Sebastolobus sp.) use wreck site as habitat. Credit: NOAA/MBARI |
The expedition was designed to build upon information gathered by the U.S. Navy and MBARI, who first recorded the aircraft's remains during expeditions in 1990 and 1991. An initial survey involving NOAA, MBARI, U.S. Geological Survey, and Moss Landing Marine Laboratories was completed in May 2005 utilizing side-scan sonar deployed from the NOAA research vessel McArthur II.
Both phases of the survey will assist in meeting the mandates of the National Historic Preservation Act (which directs Federal programs managing public lands to survey and inventory historical and archaeological properties and nominate them to the National Register of Historic Places) and the National Marine Sanctuaries Act (which directs the MBNMS to manage and protect archaeological resources such as the Macon site). This expedition aided in the assessment of the USS Macon and four Curtiss F9C-2 Sparrowhawk aircraft for eligibility to the National Register of Historic Places.
The expedition was a collaborative venture involving NOAA's National Marine Sanctuary Program, NOAA's Office of Exploration, NOAA's Preserve America Initiative, Monterey Bay Aquarium Research Institute, Stanford University, University of New Hampshire, U.S. Navy, state of California, Monterey Maritime and History Museum, and Moffett Field Historical Society and Museum. Noah Doughty, an educator from Mission College Preparatory High School in San Luis Obispo, Calif., participated as a NOAA "Teacher-at-Sea" and provided daily science and technology web-based logs.