Historic Ship Stabilization
Historic Ship Stabilization: Ship Ponding
This project includes the stabilization and storage of three historic ship remnants excavated at the Robinson Landing Site (archaeological site 44AX235). The overall goal of the project is to transport and store the timbers in Ben Brenman Pond (4800 Brenman Park Dr.) in a manner that preserves the possibility of future study and conservation when adequate funding and/or a location for permanent storage or display is available. Planning for the storage of the historic ship timbers began shortly after the ships were discovered in 2018. The implementation and fieldwork phase began in January 2021 and was completed in May 2022. Three interpretive panels were installed at Ben Brenman Pond in September 2022. Regular monitoring inspections will be carried out first in Summer 2023 and then every five years following the first annual inspection.
In the News
Return to the Depths , by Olivia Anderson, Alexandria Times, May 5, 2022
Caring for Alexandria's Merchant Fleet , Out of the Attic, Alexandria Times, May 26, 2022
Counterintuitive Preservation, by David Malakoff American Archaeology Magazine, The Archaeological Conservancy, Fall 2022
In 2018, Thunderbird Archeology, a division on Wetlands Studies and Solutions, Inc., in coordination with the City of Alexandria and the Maryland Archaeological Conservation Laboratory (MAC Lab), excavated three ship hull remnants from EYA’s development site called Robinson Landing. The discovery of the massive hull remnants resulted from implementation of the Alexandria Archaeological Protection Code. Passed by City Council in 1989, the code requires developers to hire archaeological consultants to conduct investigations prior to construction on land with the potential to contain buried sites of historical significance. Alexandria Archaeology, a division of the City’s Office of Historic Alexandria, oversees the code.
Early Alexandrians used these wooden ship remnants in a ca. late 18th century effort to make new land, extending the shoreline to the deeper channel of the Potomac River and creating a viable international port. These artifacts are tangible pieces of Alexandria’s maritime heritage, representing the City’s transformation to a bustling post-Revolutionary War harbor. The ships provide an important and unparalleled data source for understanding 18th century ship building and the land-making process.
Archaeologists, conservators, and EYA worked together to record and dismantle the hull remnants from 44AX235 into individual timbers. The City of Alexandria transported those timbers to a warehouse where they have been temporarily stored in large pools of water and kept wet and stable. A team from the Conservation Research Lab (CRL) at Texas A&M University, documented each of the over 1,000 timbers using a 3D laser scanner. From these individual scans they created physical and digital models of the three ship remnants.
A team from several city departments, archaeologists, and a Maryland Archaeological Conservation Lab conservator began developing a medium-term solution for storing the timbers shortly after they were excavated. After carefully considering several alternative solutions and locations, the team decided that Ben Brenman Pond was the most feasible option. The timbers were wrapped and transported to the pond site. Once there, a contracted archaeological consulting firm with scientific divers placed the timbers in the pond and recorded their location and site. Three interpretive signs located around Ben Brenman Pond will explain how the ship remnants were excavated, documented, and preserved. A future goal outside the scope of the current project is the selective conservation of some timbers that will not be placed in the pond. These will be retained and kept stable in a large pool of water for ease of access.
Learn more about Archaeology on the Waterfront.
Project Status Update (October 2023)
On September 19, 2023, State Underwater Archaeologist Brendan Burke kayaked across Ben Brenman Park while capturing side scan sonar data of the submerged Robinson Landing Site ship timbers. Side scan sonar detects and images objects beneath the surface of a body of water. This partnership allowed him to test out his equipment and provided us with further documentation of the historic ship timbers that were relocated to the pond last year. These images provide us with a baseline map of the timbers and pond bottom that can be used in the future to determine if anything has shifted. The center area outlined in green on these images is a blind spot caused by the kayak itself and the roughly rectangular, mostly parallel shapes on either side are the ship timbers that are secured to a geogrid on the pond bottom. Learn more in this video.
Project Status Update (June 2023)
On June 8, archaeologists and divers from AECOM, a conservator from the Maryland Archaeological Conservation Lab, and City archaeologists conducted the first monitoring inspection of the over 1,000 timbers submerged last year in Ben Brenman Pond. Overall, the curation solution appears to be working as intended. The geogrid and anchors are still in position and have not shifted since last year. The submerged timbers remain well wrapped and well attached to the geogrid. A protective layer of silt has accumulated on the timbers which mimics the original burial conditions and helps minimize biological growth by creating an anaerobic environment. All fifteen timbers that had been previously chosen to be raised to the surface for a more thorough condition assessment were easily located. These timbers are in very good shape and the wood has maintained its physical integrity while submerged in Ben Brenman Pond.
The next monitoring inspection is scheduled in five years in the spring of 2028.
Project Status Update (May 2023)
In November 2022, the City of Alexandria sent 20 ship and wharf timbers to the Maryland Archaeological Conservation Lab (MACL) for treatment. The conservation process will include submerging the timbers in polyethylene glycol and then freeze drying them to remove any remaining water. This treatment stabilizes the artifacts for future exhibit and study. The timbers will be used to interpret the city’s rich maritime heritage, providing tangible examples of 18th century ship building and land making techniques.
During the first week of June (5-9), AECOM, the City, and the MACL are scheduled to conduct the first monitoring inspection of the over 1,000 timbers submerged last year in Ben Brenman Pond. Scientific divers will assess any issues with timber storage including drift and sediment accumulation. They will pull timbers to the surface of the pond and City staff and conservators will examine the timbers’ state of preservation. Divers will report on the below water condition of timbers, geotextile, and geogrid to the City of Alexandria. This monitoring visit is anticipated to take two to three days, weather permitting, and cause minimal disruption to park operations.
Monitoring inspections will be carried out every five years following this first annual inspection.
Project Status Update (June 2022)
In May 2022, the team successfully relocated over 1,000 timbers from temporary storage at a City warehouse facility to the southern portion of the Ben Brenman Pond site by carefully wrapping, tagging, and transporting the timbers. Once delivered to the site, AECOM’s scientific divers placed the timbers in the pond and recorded their individual location.
During the ponding process, Alexandria Archaeology with the assistance of the Maryland Archaeological Conservation Lab chose a selection of ship and wharf timbers for conservation. The conservation process will include submerging the timbers in polyethylene glycol and then freeze drying them to remove any remaining water. This treatment stabilizes the artifacts for future exhibit and study. The timbers will be used to interpret the city’s rich maritime heritage, providing tangible examples of 18th century ship building and land making techniques.
Timeline and Project Updates
- Spring-Fall 2018: Excavation of three ship remnants at the Robinson Landing Site. Transfer of timbers to a city facility.
- Spring 2018 (April): Alexandria Archaeological Commission (AAC) convenes the Ships’ Committee to discuss and develop recommendations for the ships’ storage, exhibition, and interpretation within the context of the Waterfront Plan.
- Summer/Fall 2018: Planning begins with help of the Department of Project Implementation (DPI) and Maryland Archaeological Conservation Lab.
- Winter 2019/2020: Community engagement efforts begin
- June/July 2020: Project approved in FY21 CIP budget
Implementation and Fieldwork Phase
- January 2021: Request for Proposals for the Historic Ship Stabilization Project posted
- January 2022: Contract Awarded to AECOM
- April 19, 2022: Public event – Pre-Construction Meeting at Ben Brenman Pond
- May 2022: Relocation and timber placement portion of project. (Fieldwork started in spring to provide for more favorable working conditions and water temperatures)
- September 2022: Three interpretive panels installed at Ben Brenman Pond.
- November 2022: Selective conservation of timbers that were not ponded begins.
- Timber Monitoring schedule:
Part of this project requires that the timbers’ condition is regularly monitored.
One year after the relocation is complete (Summer 2023), divers will visit the site to assess any issues with timber storage including drift and sediment accumulation. They will pull timbers to the surface of the pond and City staff and conservators examine the timbers’ state of preservation. Divers will report below water condition of timbers, geotextile, and geogrid to City of Alexandria.
Monitoring inspections will be carried out every five years following the first annual inspection.
Community Meetings and Public Outreach
- Regular updates: Alexandria Archaeological Commission (AAC)
- November 2019: Parks and Recreation Commission
- January 2020: Historic Alexandria Resources Commission (HARC)
- February 2020: Cameron Station Civic Association
- November 2020: Waterfront Commission
- March 2022: Parks and Recreation Commission
- March 2022: Waterfront Commission
- April 19, 2022: Community Pre-Construction Meeting for the Historic Ship Timbers Stabilization Project
- May 2022: Cameron Station Civic Association