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

Traces of pine tar and beeswax preserved on the vessel reveal the painstaking techniques shipbuilders millennia ago used to protect their ships from the briny deep

Sonja Anderson | Daily Correspondent

August 26, 2026 2:45 p.m.

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More than two millennia ago, a Roman Republic ship carrying timber and wine sank in the Adriatic Sea, off the coast of what is now Croatia. Remarkably, the wreck offers clear evidence of an elaborate effort to waterproof its wooden hull, shielding the vessel from the corrosive effects of seawater.

Discovered in 2016 and named Ilovik-Paržine 1, the ship offers a detailed glimpse into ancient shipbuilding techniques. According to a study published this spring in Frontiers in Materials, the hull was coated with conifer-derived pitch, and one sample contained a mixture of pitch and beeswax. The findings highlight an often overlooked aspect of ancient seafaring: the organic materials used to keep wooden vessels watertight.

“In archaeology, little attention is paid to organic waterproofing materials,” says lead study author Armelle Charrié-Duhaut, an archaeometrist at the Laboratory of Mass Spectrometry of Interactions and Systems at the University of Strasbourg, in a statement. “Yet they are essential for navigation at sea or on rivers and are true witnesses of past naval technologies.”

The materials used for that purpose varied widely across time and place. As Charrié-Duhaut told Chemistry World’s Mason Wakley in April, “There’s a long history of coating” in shipbuilding. Because shipbuilders would have had access to different raw materials depending on where they lived, the coatings differ as well, she said, “Each boat has its own history.”

Charrié-Duhaut and her coauthors analyzed ten samples of the Ilovik–Paržine 1’s coating. They found molecular fingerprints characteristic of heat-treated conifer material, particularly from the Pinaceae family, indicating that the coating was made from conifer-derived tar or pitch.

One sample, however, contained a mixture of tar and beeswax, a formulation associated with ancient Greek shipbuilding and referred to in ancient sources as zopissa. Adding beeswax to tar would have made the coating more flexible and easier to apply. As Pliny the Elder wrote in Natural History, “Zopissa is the pitch, macerated with saltwater and wax, that has been scraped from off the bottoms of ships.”

The use of zopissa is an “archaic Greek tradition,” Charrié-Duhaut and study co-author Quentin Couillebault, a bioarchaeologist at Aix-Marseille University, tell Gizmodo’s Gayoung Lee. Its presence on a Roman ship built centuries later, they explain, is consistent with the “circulation of technical knowledge” and “technological transfer across the Mediterranean basin.”

But the coating revealed more than its composition.

Sticky pitch can trap airborne pollen—tiny grains released by plants during reproduction. By analyzing the types and relative abundance of pollen lodged in the material, the researchers gained clues about where it might have been produced or applied.

The pollen preserved in the pitches points to environments where holm oak, pine, olive, alder, ash and hazel grew. These plants are characteristic of Mediterranean and Adriatic coasts and valleys and are consistent with the ship’s proposed construction area near Brindisi, on Italy’s southeastern coast. Previous analysis of the ship’s ballast found a strong geological match with the Brindisi region and suggested that the ballast was loaded there when the ship was built.

Statistical analysis identified four to five distinct coating batches, which may reflect successive repairs or separate applications during construction or refitting. Small amounts of fir and beech pollen found in some samples are consistent with mountainous environments in the northeastern Adriatic, including areas near Istria and Dalmatia, close to the ship’s final resting place. The roughly 70-foot-long ship sank in the middle of the second century B.C.E., according to a report detailing its 2016 discovery.

“Our study highlights navigation routes based on clues related to the ship’s construction areas and, especially, to the different phases of coating application on the ship,” Charrié-Duhaut tells Popular Science’s Margherita Bassi. “It suggests that this vessel traveled between the western Adriatic coast, where it was likely built and where the first layer of coating was applied, and the eastern Adriatic coast.”

The findings also shed light on how ancient ships were maintained during their voyages.

“While it seems obvious that ships sailing long distances need repairs, it’s simply not easy to demonstrate this,” Charrié-Duhaut concludes. “Pollen has been very useful in identifying different coatings where the molecular profiles were identical.”

Sonja Anderson is a daily correspondent for Smithsonian magazine who covers art, archaeology and culture, from newly discovered artifacts to the latest art heists.