The Monterrey Shipwreck: Mapping the Site

OET's ROV Hercules mapping the Monterrey Shipwreck
OET’s ROV Hercules mapping the Monterrey Shipwreck.

National Geographic Grantee and Texas State University Research Faculty Frederick “Fritz” Hanselmann and a team of leading archaeologists are conducting an expedition to the Monterrey Shipwreck in order to carry out the deepest archaeological shipwreck excavation ever in North America. Follow along with Fritz’s updates from the field.

By Fritz Hanselmann

One of the most important aspects of archaeological research is mapping a site.  We map for a number of reasons: to understand the context of the artifacts in their location, site interpretation, and to have a record of where artifacts were located prior to excavation.  Basically, that means that we try to understand how a site was formed, how a site and its associated artifacts were used, and make a record prior to disturbance through recovering artifacts for further in depth study.  My team member Chris Horrell of BSEE adds that mapping is one of the most critical elements of any archaeological project because it provides provenience for all the artifacts, and provides a tool that ultimately aids us in interpreting this incredible site.  In the case of the Monterrey Shipwreck, we are interested in not only understanding how the ship wrecked, but also the human stories behind the ship.  How did the crew live?  What did they do?  What was the vessel’s nationality and function?  What role did the ship play in the maritime history of the Gulf of Mexico and the surrounding regions?  The first step to answering these questions is to map the site.

OET's ROV Hercules positions a compatt for LBL mapping
OET’s ROV Hercules positions a compatt for LBL mapping.

Mapping a shipwreck in 4,300 feet of water is no easy feat.  In shallow water, a cost effective and simple method is carried out using divers, slates, paper, and measuring tapes.  At such a great depth where the human body cannot survive by itself, we use the ROV’s Hercules and Argus as our avatars through which we conduct our research.  In order to map the Monterrey Shipwreck, we pilot Hercules to position a long baseline (or LBL) array, which consists of a series of yellow boxes on tripods placed around the site.  These boxes are called compatts and they give off sonar frequencies which allow Hercules to have marked electronic waypoints and create an extremely accurate map by running lines across the shipwreck area and taking measurements use Blue View laser imaging and capturing still photos.  As an interesting side note, this is only the third shipwreck ever be mapped using Blue View technology!  Once the measurements and the photos are beamed back to the Nautilus at the surface, they can then be combined after the fact to create a map and a photomosaic of the site, which is essentially an overall image made up of many single images stitched together.  Ian Vaughn, our project mapping specialist, estimates that it took around 800-900 images for the photomosaic, over 100,000 laser measurements, and close to 600,000 total images and measurements during our latest efforts.  This type of detailed mapping truly allows us to interpret the site with a high degree of accuracy and we are now able to move on to the excavation and artifact recovery phase.

Funding provided by foundations and individual donors through the Meadows Center for Water and the Environment and the Office of Advancement at Texas State University and the Way Family Foundation. 

NEXT: Initial Artifact Recovery


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Meet the Author
Frederick "Fritz" Hanselmann is Research Faculty, who serves as the Chief Underwater Archaeologist and Diving Program Director with the Meadows Center for Water and the Environment at Texas State University. He is also the director of The Meadows Center's Underwater Archaeology and Exploration Initiative. Fritz learned how to swim at age three, and has been in love with the water ever since, having been taught to breath hold dive by his grandfather diving for golf balls tied in a sock in the Gulf of Mexico. Having worked on underwater sites from a wide variety of time periods, his research ranges from submerged prehistoric deposits in springs and caves to historic shipwrecks in Latin America and the Caribbean, including the wreck of the Quedagh Merchant, abandoned by Captain Kidd in 1699 off the coast of Hispaniola. Fritz led the first-ever archaeological survey of the mouth of the Chagres River in Panama as the initial phase of the ongoing Río Chagres Maritime Landscape Study. One aspect of this study is the Lost Ships of Henry Morgan Project, the search for the famous privateer's sunken ships. He is one of the Principal Investigators of the Monterrey Shipwreck Project in the Gulf of Mexico, which is the deepest shipwreck excavation ever conducted in North America, in collaboration with three federal agencies, three universities, and three non-profit organizations. Fritz is also the co-director of the Sunken Ships of Colombia project, which focuses on finding, documenting, studying, and managing historic shipwrecks along the Caribbean coast of Colombia. The Spring Lake Underwater Archaeology Project on the university's campus also falls under his supervision and he assists other projects in Mexico and Texas as part of the Initiative. Fritz also focuses on capacity building and training for archaeologists and heritage managers in less developed countries, as well as the development of marine protected areas and underwater preserves. He is a GUE Cave and Technical Diver, a Nautical Archaeology Society Tutor, a certified scuba instructor, an ambassador for Aquadive Watches, and a fellow of the Explorer’s Club. Fritz regularly gives public lectures and presentations for museums, universities, and other organizations.