Tuesday, April 4th, 2017
There’s news about the large piece of an 18th century ship discovered on the Potomac riverfront in Alexandria, Virginia, in December of 2015. Archaeologists have been studying the 50-foot section of hull which was deliberately scuttled to fill waterfront property. Property records were able to narrow down the date of the ship’s burial to between 1775 and 1798, but it took dendrochronological analysis to discover the ship’s age. The tree-rings in the planks reveal that the trees used to make the timber were cut down in Boston after 1741.
[City of Alexandria archaeologist Benjamin] Skolnik said some of the earliest tree rings from the ship are from 1603 — four years before John Smith showed up in Jamestown and 17 years before the Pilgrims showed up in Massachusetts.
“So the wood in the ship comes from a time of early American history that even predates the earliest permanent English settlements here in the New World,” he said.
Preserving these venerable timbers poses a great challenge. The surviving section of the hull includes some of the keel, frame, bow stem, stern, exterior boards and interior flooring. The archaeological team dismantled the ship one board at a time, numbering, tagging and inventorying each timber so it could be reassembled in its original configuration once the wood was stabilized. Getting to that point was by no means a foregone conclusion, however.
The immediate problem when I first wrote about this find early last year was locating a space that could accommodate 50 feet worth of ship timbers in a climate and humidity controlled environment. The wood had to be kept in water to keep it from drying out and warping, and there were no facilities that could accommodate the sheer size of the 18th century ship parts. The solution was a building known as the “bus barn,” a large depot used by the City of Alexandria to store emergency vehicles and school buses.
The ship’s timbers were transported to the bus barn by archaeologists and volunteers. The largest pieces were submerged in two massive water tanks lined with plastic. The smaller timbers were placed on a tarp, hosed down and covered with another tarp to create a wood-preserving tarp sandwich. The ship has been in the bus barn since January of 2016.
The next step is permanently preserving the wood with polyethylene glycol (PEG), a waxy substance that gradually replaces the water in wood leaving it supple and stable, the same treatment that preserved the Mary Rose and the Vasa. The problem with PEG is that it’s expensive and it takes decades, but that time can be significantly shortened if the PEG treatment is followed by freeze-drying, as was done with French explorer La Salle’s frigate La Belle.
Even so, the conservation process will take five or six years and will cost more than the city can afford by itself. So far, the costs have been defrayed by a combination of private donations, grants and city funds, but the long-term preservation and display of the ship requires significant additional funding. It’s worth it, though.
“One of the appeals of the ship is, I mean it’s something large, and it’s very visible and very tangible piece of the past that you know, sometimes when you’re in school and you’re learning about history, it’s sort of in the abstract. You sort of have to imagine it, but if you have a 46-and-a-half-foot chunk of a ship standing in front of you, I mean it’s very very visible and very very real,” Archeologist Benjamin Skolnik said.
The City of Alexandria has set up a donation page on its website.