How Tree Rings Helped Identify a Rhode Island Whaler Lost at Sea

A whaling ship known as the Dolphin left the shores of Rhode Island in 1858 for its last voyage, never to return to port again. The 42-person crew was rescued the following year from the waters of the southern Atlantic Ocean by an Argentine mariner, and its captain continued to command voyages a decade later, but the ship had continued to exist only in memory and written records.

That was until 2004, when the remains of a shipwreck were found off the coast of Puerto Madryn, a gulf city by the northern shores of the Patagonian region of Argentina.

Scholars speculated that the remains might have been the Dolphin, though they were careful not to state so conclusively for lack of evidence. New research, published last month in the scholarly journal Dendrochronologia, allowed researchers to identify the shipwreck to a high degree of certainty, said Ignacio Mundo, the lead author and an adjunct researcher with the Dendrochronology and Environmental History Laboratory at the National Scientific and Technical Research Council in Mendoza, Argentina.

The finding was possible because of the analysis of a kind of fingerprint of the ship itself: The rings on its wooden planks and futtocks, or curved timber pieces.

The effort to identify the whaler’s old remains required the collaboration of experts from different scientific disciplines, including the input of archaeologists, anthropologists and dendrochronologists, or tree-ring experts like Dr. Mundo.

“I find it incredible that starting with a piece of wood on a beach, we could make the connection to a boat that was built in Rhode Island,” he said.

The finding corresponds with local accounts of the time that the ship had been wrecked in that part of South America. The remains of caldrons, used to melt the wax blubber from whales, were also found, Dr. Mundo said. In the 1850s, the region was navigated by North American and European explorers who were searching for whales to hunt for commercial exploitation. Products derived from the hunt included the oil, which was used in lamps and as a lubricant, and wax for candles and soap. Whale bones were used in small household items that are now made with plastic.

New England played a significant role in the whale trade from the mid-1770s through the 1850s. Demand for whale oil dropped when petroleum, which had begun to supplant it around the mid-19th century, gained popularity.

The Town of Warren, Rhode Island, from which the Dolphin set sail, had been a popular spot for whaling dating back to colonial times, said Michael P. Dyer, the curator of maritime history at the New Bedford Whaling Museum in New Bedford, Mass.

“Rhode Island has a great whaling history,” he said.

To him, the search for the Dolphin is now a closed case. The tree-ring aging confirmed the historical record, said Mr. Dyer, who said he hopes dendrochronology will continue to offer insights into the identities of other shipwrecks.

“When you have evidence like this shipwreck that lines up with the historical record as nicely as it does, then you’ve got something to hang your hat on,” Mr. Dyer added. “You can think a little bit more firmly about the facts of history.”

The findings have made headlines from Rhode Island to places far away from the Dolphin’s home port and in publications tracking developments in the sciences, as tree rings open up the search for clues in historical research.

Tree-ring analysis helped researchers to pinpoint the ages of the wood types found among the remains of the Dolphin, allowing them to date the pine to 1810 and the oak to 1849, Dr. Mundo said. The apparent discrepancy in those ages resulted from some rings being lost when the planks were made to build the boat.

“Obviously, they weren’t imagining that 200 years later, we’d be using this wood to date the ship,” he said.

Samples with more than 75 rings, the minimum amount sought to ensure accuracy, were compared to a network of tree ring data from the Northeast and Southeast regions of the United States, according to the research.

“The tree-ring patterns in the cross-sections were visually inspected,” the research paper said, “and then the annual ring widths were measured to the nearest 0.001 mm.”

Little is known about whalers in Patagonia today, said Cristian Murray, a marine archaeologist with the National Institute of Anthropology and Latin American Thought in Buenos Aires. To him, the Dolphin’s discovery adds to the knowledge of the dynamic between international whalers and the communities near the waters they frequented.

For example, Mr. Murray wonders: Were the whalers in contact with Indigenous people still living in South America at the time? What was their relationship with the people in the region? Did they trade, or learn from each other?

“For me, one of the greatest values of this site from an archaeological and historic point of view, is to be able to answer a lot of questions about that activity in that period and in this region,” he said.

This research contributes to a larger project Mr. Murray is working on about the exploitation of marine resources in Patagonia in the 19th century, not just whales but also penguins, seals and seabirds.

Residents of that seashore region in Argentina who work at a museum in Puerto Madryn discovered the shipwreck when the tide was low, Mónica Grosso, an archaeologist with the National Institute, said. They were also involved at the site during the excavation and through the further studies of the findings.

“The shipwreck undergoes different processes through which it deteriorates and dismantles, so interpreting this is a complex process,” she said.

Dr. Grosso and Mr. Murray have spent about two decades working to find out more about the shipwreck, and she sees the results so far as the culmination of interdisciplinary collaboration. Adding the tree-ring analysis’ conclusions to what had been mostly research in maritime archaeology allowed for some longtime questions to be answered.

“The most exciting part was when we confirmed the suspicions that this could have been a whaling boat,” she said.

The wood from the shipwreck was compared to a database provided by Columbia University, said Mukund Palat Rao, a postdoctoral researcher who specializes in dendrochronology. He joined the project two years ago because it is similar to his work, which focuses on figuring out where the timbers used to build New York City originated.

“We get these glimpses into past human history,” he said, “and the interconnectedness of how we were moving around.”