A Brittle Coating on a 2,200-Year-Old Roman Shipwreck Reveals How Ancient Sailors Kept Their Ships Afloat

Over two thousand years ago, a Roman Republic ship laden with timber and wine met its demise in the Adriatic Sea, off the coast of modern-day Croatia. Remarkably, the 2016 discovery of the wreckage, dubbed Ilovik–Paržine 1, reveals the intricate process ancient sailors employed to waterproof their wooden vessels. According to a recently published study in Frontiers in Materials, the ship's hull was coated with a pitch derived from conifer trees, which served as an effective barrier against the corrosive effects of seawater.

The research, conducted by an international team led by Armelle Charrié-Duhaut, an archaeometrist at the University of Strasbourg, underscores the often overlooked significance of organic materials in ancient seafaring. "In archaeology, little attention is paid to organic waterproofing materials," Charrié-Duhaut notes, highlighting their crucial role in seafaring.

The study analyzed ten samples of the Ilovik–Paržine 1's coating, identifying molecular signatures of heat-treated conifer material, predominantly from the Pinaceae family. One sample contained a mixture of tar and beeswax, a formulation known as zopissa, a Greek maritime tradition dating back centuries. Beezwsax was added to the tar to enhance the coating's flexibility and ease of application.

Pollen trapped within the pitch offers additional insights into the ship's origin and maintenance. The preserved pollen grains indicate the presence of Mediterranean and Adriatic coastal flora, such as holm oak, pine, olive, alder, ash, and hazel. These plants are consistent with the ship's proposed construction site near Brindisi, on Italy's southeastern coast.

Geological analysis of the ship's ballast further supports this hypothesis, suggesting that the ballast was loaded in Brindisi during construction. The presence of four to five distinct coating batches implies successive repairs or separate applications during the ship's construction or refitting. The findings shed light on ancient shipbuilding techniques and maintenance practices, emphasizing the importance of navigation routes and the practical challenges of maintaining long-distance voyages.

The study highlights the connections between shipbuilding traditions across the Mediterranean basin, revealing the circulation of technical knowledge and technological transfer throughout history.