2,200-Year-Old Roman Shipwreck Unlocks Ancient Waterproofing Secrets
Researchers decode the waterproofing techniques used on a Roman-era shipwreck off the coast of Croatia.
1Waterproofing in Ancient Maritime History
Throughout the history of sea voyages, ships have been coated to protect them from water, salt, microorganisms, and marine creatures like shipworms. However, until the mid-20th century, little research was conducted on non-wood materials used in ancient shipbuilding. Waterproof coatings in particular remain largely mysterious. A new study published in Frontiers in Materials is helping fill this gap by analyzing protective coatings on a 2,200-year-old Roman shipwreck.
2Intriguing Discovery: The Zopissa Mixture
Researchers from France and Croatia analyzed the protective coatings on the Ilovik-Paržine 1 shipwreck, which sank off modern-day Croatia during the Roman Republic era. They found two types of coatings: one made of pine tar (pitch) and another consisting of a pine tar and beeswax mixture. This combination, known to Greek shipbuilders as zopissa, created a more flexible adhesive that was easier to apply when heated.
3Tracing Geography Through Pollen Analysis
Since pitch is naturally sticky, it can capture and preserve pollen from nearby vegetation for extended periods. By studying the types and relative abundance of pollen trapped in the coatings, researchers could narrow down where some of the pitch might have been produced or reapplied during repairs. Pollen recovered from the wreck indicated diverse environments typical of Mediterranean and Adriatic coasts and valleys.
4The Ship's Probable Construction Site
Previous research on the vessel's ballast suggested it was built in Brundisium (modern Brindisi) on Italy's southeastern coast. The new pollen evidence indicates some coatings may have been applied in this area too. However, other layers might have been added along the northeastern Adriatic coast, closer to where the wreck was ultimately discovered near Croatia.
5Multiple Repair Layers Revealed
Analysis suggests the ship received four to five separate coating applications over time. While the stern and midsection appear to have been covered with the same material, researchers identified three distinct coating batches at the bow. This pattern may indicate repeated repairs using materials sourced from different locations around the Mediterranean region.
6Shedding Light on Maritime Technology History
Lead author Dr. Armelle Charri notes, 'In archaeology, little attention is paid to organic waterproofing materials. Yet they are essential for sea or river navigation and are true witnesses of past naval technologies.' Such studies provide insights into how specific Adriatic characteristics led local populations to develop unique shipbuilding traditions.
7Analytical Methods and Findings
Researchers employed structural, molecular, and pollen analyses to examine the coatings. Using techniques like mass spectrometry, they identified and measured unknown substances within complex organic mixtures. Analysis of 10 coating samples revealed the biological origins of natural materials used on the vessel. Molecular fingerprinting showed each sample was dominated by heated coniferous resin or pitch.
8The Significance of Ancient Maritime Techniques
This study makes important contributions to our understanding of ancient maritime technologies. While it's obvious that long-distance ships needed repairs, proving this isn't always straightforward. Pollen analysis proved particularly useful in distinguishing different coatings when molecular profiles were identical. Such interdisciplinary work continues to expand our knowledge of ancient shipbuilding techniques.