Thunderbird Archeology, a division of Wetland Studies and Solutions, Inc., retained VIKA Virginia’s surveying services to conduct a 3D laser scan of a buried historic treasure in Old Town, Alexandria — a large, heavy ship likely scuttled in the late 1770s to 1790s.
The sunken ship’s bow was discovered as construction crews were excavating the site for construction of the 120-room Indigo Hotel at 220 South Union Street. Archaeologists found the partial hull of the ship in the same area where, several months ago, a builder also found the 1755 foundation of a warehouse that may have been Alexandria’s first public building.
The nearly 50-foot long remnant of the ship’s keel, frame, stern, and flooring is estimated to be about one-third the size of the ship’s original hull. As a nearly 150-foot vessel, the ship was likely built to carry heavy cargo or serve as a military ship.
This historical find is particularly exciting because the City of Alexandria has no records of the ship’s existence. Ship remnants may have been placed at their location to expand the shoreline along the Potomac River. The blackened bow did not decay because it was buried and preserved. The huge brick footing of a later warehouse did not disturb it. The City of Alexandria may preserve the ship for public display and salvage it for future study and possible conservation and reconstruction.
VIKA’s services for this exciting project included conducting 3D Lidar scans from several vantage points to capture as much of the shipwreck as possible and with a high level of resolution to capture diagnostic information such as nails, trunnels, and hand-hewn marks on the wood. VIKA also performed color 3D photogrammetry during the scanning.
Three high definition laser scans of the shipwreck were performed to capture the various levels of wood, as they were removed in conjunction with the archeological work:
- First scan aimed to capture ceiling planks and framing. The soils underneath the planks were archeologically excavated and screened for artifacts by Thunderbird Archeology prior to the second scan of the framing timbers.
- During the second scan, the framing and futtocks were mapped, tagged, and removed with the assistance of the City of Alexandria’s archeological staff and the US Department of the Navy.
- The third and final scan was of the remaining hull planking.
VIKA collected and processed the scanning data, and registered the information in a 3D electronic Point Cloud which was provided to Thunderbird Archeology, the archeological consultant, and the City of Alexandria for interpretation.
In addition, we prepared AutoCAD drawings showing the three stages of archeological excavation and also prepared other appropriate 2D drawings of ship details from the 3D Point Cloud data for use by the consultant in the archaeological evaluation report. In addition, we made the photogrammetry images available for use in the report.