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


  1. Debbi Head
    July 21, 2013, 2:53 pm

    This is so exciting! The world is watching and to be able to follow along live is truly amazing! We have posted the link on our Facebook page and people are loving it. You rock! Hello to Amy.