Approximately 70 miles west of Key West, Florida, lies a cluster of seven islands, accessible only by boat or seaplane, which comprise the federally-protected Dry Tortugas National Park. This isolated outpost is home to Fort Jefferson, a massive but unfinished former military installation built in the mid-19th Century as part of a coastal defense system against piracy and other threats.

Known as the “Guardian of the Gulf,” the fortress incorporated some of the most sophisticated war technology of its era, including specialized wrought iron shutters used to protect the cannon openings. The fort’s designers could not anticipate, however, that in a saltwater environment, wrought iron would quickly rust and expand. Over time, this expansion has pushed thousands of the surrounding bricks into the waters below and caused serious structural damage to Fort Jefferson’s walls.

Dry Tortugas National Park has initiated a multi-phased, multi-year preservation project to restore and stabilize this unique piece of American history. PBS&J recently contributed to the restoration efforts by completing a comprehensive high definition survey of the fort. The project involved establishment of permanent survey monuments, horizontal and vertical survey control, and a detailed survey of the wall faces. Deliverables included 3D drawing files and sketches that provided a detailed condition assessment for each of the damaged wall openings that had been used for military weaponry.

The team was led by Roberto Mantecon, PSM, project director in the national survey group, accompanied by Phil Barker (Houston, Texas) and Chad Taylor (Miami, Florida). The entire fort was scanned in two days, reflecting the technological capabilities and “can-do” attitude of the group.