Maritime historian Norman Brouwer had suggested that the unusually crafted sailboat was from a small rural shipyard and the trees for its timber from the same forest. "The data we see suggest something very similar," says Neil Pederson of the Lamont-Doherty Earth Observatory's Tree Ring Lab in Palisades, NY. "It's an interesting intersection in experts," he told Discovery News. He was part of a four-person dendrochronology team from the Tree Ring Lab working on samples of the vessel's white oak planks and its hickory keel. Other tree species used in the boat's construction included spruce and southern yellow pine, reported wood deterioration researcher Robert Blanchette of the University of Maine.
Looking up tree ring patterns for white oak timber samples is like hunting down a family's genealogy. To get the most accurate result, teams of people around the world need to have already done the manual labor of counting rings and entering forest timber chronologies into a database. Then it's a matter of sleuthing through generations of tree life-cycles to find a pattern that fits: where the timber samples and the trees share the same local climate of wet and dry years allowing them to make matching patterns of wide rings and skinny rings. So where to start?
An oak sailboat in New York could have originated anywhere in Europe or North America. Dutch ships original carried sloops across the Atlantic in the 1600s. Whose side was this sailboat on? Pederson said when they first heard of the find they weren't sure if they could track the soggy wood - when the team saw the keelson, the upper floor of the hull, the planks looked like white oak. When Blanchette confirmed their suspicions but added that they'd be getting a sample of hickory from the keel, the tree-ring team were relieved. The hickory keel sample was key - "it's been extinct in Europe for two million years or so," Pederson said.
So once the team did their own grueling process of slowly drying the timbers, waiting to see if the wood would decay, then sanding the samples, and counting the rings, sometimes as thin as one thousandth of a millimeter, and hoping each sample would provide at least 100 years of rings to make the sample comparable to other chronologies then the scientists got started looking for a match. They used a computer system to compare their samples with chronologies of forests from the New York State's Hudson Valley and then took a stab at a historical timber chronology they have from Philadelphia, "and that just about nailed it – really good," said Pederson.
When the wreck was first found the archeologists were confused as to whether they were looking at the front (stem) or back (stern) of the vessel. Turns out the sloop was rounded at both ends. Last month the Port Authority of New York and New Jersey excavated behind a concrete wall, where archeologists from the firm AKRF hoped to find remnants from the bow, where the figurehead and bowsprit thrust forward over the curving stem, the part of the sailboat that forms a bowshock of cresting waves and a good place to look for dolphins when under sail.
Eventually AKRF did recover a large portion of the structural part of the front of the boat. Now that material is with the Center for Maritime Archaeology and Conservation at Texas A&M University, where Director Kevin Crisman and his team are assisting the excavators with storage of the timbers. Alum and archeologist Carrie Fulton, now at Cornell University, spent a week cleaning, inspecting, and recording the new finds using stereophotography to generate 3D models.
One image shows part of the Roman numeral II, a draft mark carved into the lower stem indicating the point where the vessel was two feet from the bottom of the keel. With light loads this mark would likely hover just at the water line indicating to the crew that they would run aground if they traveled through water that was less than two feet deep, an event they likely did often.
Read more and see pictures at Discovery News
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