Colonial Shipwrecks of Colombia: Mapping the Tortuga Wreck Site and Surveying the Reef

Archaeologists Andres Diaz, Chris Horrell, and diver Felipe Mergueitio Sicard measure and map one of the cannons on the site. Credit: Fritz Hanselmann/The Meadows Center for Water and the Environment at Texas State University
Archaeologists Andres Diaz, Chris Horrell, and diver Felipe Mergueitio Sicard measure and map one of the cannons on the site.
Credit: Fritz Hanselmann/The Meadows Center for Water and the Environment at Texas State University

National Geographic Grantee and Texas State University Research Faculty Frederick “Fritz” Hanselmann and a top-notch team of archaeologists from Colombia and the United States are leading an expedition to locate and document historic shipwrecks off of the Caribbean coast of Colombia. Follow along with Fritz’s updates from the field.

With one last day remaining on the first phase of our survey off the coast of Cartagena, we continue to map and document what we are now calling the Tortuga Wreck, due to the recent siting of a sea turtle on the site and for the wonderful assistance of our colleagues at La Tortuga Dive School.

Much information can be gained simply from measuring and mapping a site, even one that consists mostly of large ferrous – or iron – artifacts.  Our goals for the dives today were to measure all of the anchors and cannons, so that we can return to shore and create an accurate site map drawn to scale. Mapping allows us to better understand the site and to attempt to interpret, or hypothesize, potential answers to questions of identity, function, nationality, and the cause of its sinking.  Since the depth of the site is shallow and varies from 15 – 30 feet, it is perfect for the use of scuba and the cost-effective method of physically mapping using pencils, slates, and measuring tapes.  Mapping requires a minimum of two to three divers: one to hold the end of the tape, one to hold the reel, and another to write down the information.  In this case, we had two mapping teams focusing on two of the sections of the site that hold the most promise to provide data.  Length, width, and measurements of various features of the anchors and cannons will allow us to try to “type” their sizes with known artillery and anchors of different countries and time periods.  Clearly, excavation and conservation would provide much more detailed information, but as we are just beginning to explore these waters, maintaining the integrity of the site is of the utmost importance, especially when considering future long term research efforts.

We were also curious to know what else might be in the area surrounding the Tortuga Wreck, so after finalizing our dives, we deployed the magnetometer, a Marine Magnetics Explorer.  A magnetometer functions similar to a metal detector, but has a much broader range, able to detect large metallic signatures, or anomalies, in the magnetic signature of a given geographic region.  The magnetometer allows us to conduct geophysical and electronic mapping.  What this means for us as archaeologists is that we have a tool that is extremely useful for finding historic shipwrecks as many of them have different characteristics and features that are made of iron.

SeaSPY Magnetometer Credit: Marine Magnetics
Explorer Magnetometer
Credit: Marine Magnetics

The mag is towed from the stern of the boat and the boat is driven in lanes predetermined in the GPS and survey software, which allow us to cover an area accurately and efficiently.  We spent the rest of our afternoon “magging” the surrounding area of the site and then returned home to process our data, our notes and measurements as well as the mag survey results.

Later tonight, we will pack our bags and prepare for what will be an adventurous trip to the next leg of our project: surveying the coast of the one of the earliest Spanish settlements in the New World, Santa Maria la Antigua del Darién founded by Vasco Nuñez de Balboa in 1510, in the southernmost portion of the Darién Jungle.  As this is new territory for us, we will most likely be off of the grid for this portion of the fieldwork and I will post more as soon as we have internet access again.  Arrival at our new digs will take two flights, one bus ride, and one boat ride.

Funding and support provided by a National Geographic Society-Waitt Grant, the Universidad del Norte, the Instituto Colombiano de Antropología e Historia, the Centro de Investigaciones Oceanográficas e Hidrográficas of the Dirección General Marítima, the Agencia Presidencial de Cooperación Internacional de ColombiaLa Tortuga Dive SchoolHalcyon Dive Systems, the Way Family Foundation, and The Meadows Center for Water and the Environment at Texas State University.


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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.