On February 11, 2010, seventy five years after the dirigible USS Macon crashed into the Pacific Ocean, its crash site was added to the National Register of Historic Places. This underwater wreck was extensively documented using MBARI submersibles.
At 785 feet long (similar in size to the RMS Titanic), the USS Macon was one of the largest dirigibles ever built. Designed for military surveillance, it carried five Sparrowhawk biplanes that could be launched and recovered in mid-air. Only two years after its construction, however, the Macon crashed into the ocean off the Big Sur coast during a storm on February 12, 1935, and sank to the seafloor. All but two of its crew were rescued by nearby Navy ships. The exact location of the wreck was unknown until 1990, when MBARI's Chris Grech used Navy and MBARI vehicles to search the seafloor and find debris that could only have come from the Macon.
In 2006 MBARI collaborated with the National Oceanic and Atmospheric Administration (NOAA), the Monterey Bay National Marine Sanctuary, and other organizations on an expedition to explore and map the debris of the USS Macon. Using MBARI's remotely operated vehicle (ROV) Tiburon, the team scoured thousands of square meters of seafloor. The expedition returned with hundreds of photographs and dozens of hours of video showing pieces of the dirigible and of the biplanes that it carried when it plunged into the sea.
After analyzing the images and video, historical researchers identified remnants of the Macon's airship-hangar bay, its four Sparrowhawks, five of its eight engines, and various structural components. Video from the dives also showed numerous objects used in the daily life of the crew on board the airship, including sections of a stove, the enlisted men's dining table, and chairs and desks from an officer's or meteorologist's office. All these items were made of aluminum (to save weight). The expedition did not recover any portions of the wreck, but only documented its extent and condition.
The extensive documentation of the wreck of the USS Macon was instrumental in allowing this underwater feature to be added to the National Register of Historical Places. According to Paul Michel, Monterey Bay National Marine Sanctuary superintendent: "The National Register listing highlights the importance of protecting the wreck site and its artifacts for further understanding of our past." The National Register is the nation's official list of cultural places considered worth preserving. Places listed in the National Register can also qualify for federal grants for historic preservation.
As Bruce Terrell, senior archaeologist, NOAA Office of National Marine Sanctuaries Maritime Heritage Program points out: "Dirigibles were an important development in the history of aviation and the Macon's remains represent the only archaeologically-documented example of such aircraft in the United States and possibly the world." MBARI is proud to have played a role in helping preserve this unique underwater historical site.