Ancient Shipwreck’s Brittle Coating Reveals Mediterranean Waterproofing Techniques

A Roman Republic-era ship that sank in the Adriatic Sea more than 2,000 years ago has preserved evidence of how ancient shipwrights protected wooden hulls from seawater. Researchers examining the Ilovik-Paržine 1 wreck found that its hull had been coated with material made from heat-treated conifers. The wreck, discovered off the coast of present-day Croatia in 2016, is about 70 feet long. It was carrying timber and wine when it sank in the middle of the second century B.C.E. Logs and amphorae remain among the material associated with the vessel. For a study published in Frontiers in Materials, researchers analyzed 10 samples of the hull coating. Molecular traces pointed to tar or pitch derived from conifers, particularly trees in the Pinaceae family. One sample also contained beeswax mixed with the pitch. That combination is associated with an ancient Greek shipbuilding formulation known as zopissa. Adding wax would have made the pitch more flexible and easier to spread. Its presence on a later Roman vessel suggests that shipbuilding knowledge circulated across the Mediterranean, according to the study’s authors. The coating also trapped pollen released by nearby plants. Researchers found grains associated with holm oak, pine, olive, alder, ash and hazel—vegetation found along Mediterranean and Adriatic coasts and in nearby valleys. Those findings are consistent with the idea that the ship was built near Brindisi, on Italy’s southeastern coast. Earlier analysis of the ship’s ballast had also linked it strongly to that region. The pollen evidence may indicate that the ship received coatings in more than one place or at different times. Statistical analysis identified four or five distinct batches, potentially reflecting separate applications during construction, repairs or refitting. Small quantities of fir and beech pollen in some samples are consistent with mountainous areas of the northeastern Adriatic, including parts of Istria and Dalmatia near the wreck’s final location. Together, the coating and pollen evidence suggests that the vessel traveled from the western Adriatic, where it was probably built and initially treated, toward the eastern Adriatic. The findings also provide unusually direct evidence that ancient ships were maintained during their voyages—an ordinary necessity of long-distance sailing that is difficult to demonstrate archaeologically.