The Challenges of Underwater Excavation
A story of the discovery and excavation of a mid-third century BCE Punic shipwreck, led by Honor Frost, a pioneer in the field of underwater archaeology
By Honor Frost Foundation
Archive images copyright of the Honor Frost Archive, Special Collections, University of Southampton
Survey of the Punic Ship (1972-08-10)Honor Frost Foundation
The Excavation
Excavation of the Punic ship commenced immediately, revealing part of the sternpost, a large portion of the keel, and the port side of the hull that remarkably had survived up to the waterline. Five V-shaped, transversal floor timbers also survived, along with a number of frames. Overall, the hull remains measured about 10 metres in length and 3 metres in width.
Punic ship timbers (1971) by Honor FrostHonor Frost Foundation
Preserved for over 2,000 years
Despite being found so close to the shore in shallow waters, the hull and its contents were remarkably well preserved primarily due to the sandy environment of the seabed.
Honor also believed that the Poseidonia seagrass that formed dense mattes across the site, whilst presenting a challenge to excavation, created conditions that resulted in the exceptional preservation of the buried ship timbers.
Divers working on the site (1971-08-21)Honor Frost Foundation
Working in a challenging environment
Excavation was challenging in shallow waters, deep sands constantly moving back and forth across the site, and unpredictable winds made working conditions difficult. As a result, the team had to constantly adjust their work programme and equipment to reduce the risk of damage to the site.
Conditions were most challenging in 1973, when a deep sand bank was found to have entirely buried the site over the winter. Honor is quoted as saying, “The wreck had become my Moby Dick”. (Frost 1981).
Tracing the timbers (1973)Honor Frost Foundation
The presence of large quantities of ballast stones indicated that the ship had likely not been carrying cargo when it sank, as less ballast is required for safe sailing when a cargo is loaded. The fact that the hull was almost empty made recording more straightforward, enabling the team to complete the excavation in four seasons.
Marsala Site plan (1972) by Honor FrostHonor Frost Foundation
Creating a site plan
Despite the various challenges, the team produced a conventional two-dimensional plan of the site. The hull planking was traced under water using sheets of polythene. Every object was recorded and plotted on site before being recovered. The frames and other timbers were also recorded to full scale after recovery. Once on land, all finds were drawn and photographed.
Taking a section with the comb (1972-08-29)Honor Frost Foundation
Recording sections
Three-dimensional recording was also required to document the hull shape. To do so the team developed a metal comb-like tool that worked like a contour gauge. Once the hull sections were recorded under water, the tool replicating the section was passed to the illustrator waiting in the boat above, and the hull shape transferred to the site plan.
Schematic Section (1981) by Honor FrostHonor Frost Foundation
Schematic section
Careful recording of the hull sections offered clues about the actual process of the ship's sinking. Measurements showed that the keel inclined at an angle such that the prow would likely have protruded above the surface of the shallow water when the vessel sank, whilst the stern remained firmly stuck in the sand.
Photography (1973)Honor Frost Foundation
Photography
The shallow depth made underwater photography particularly challenging: the water was often cloudy and long shots were rarely possible. Photography was used to document the Punic markings painted on the timbers, but many signs quickly disintegrated as soon as the timber was touched or exposed to light.
This exhibition was created by the Honor Frost Foundation, archive images are courtesy of the Honor Frost Archive, Special Collections, Hartley Library, University of Southampton.
The Regional Archaeology Museum of Lilybaeum-Marsala
The Alagna Family and the Cantine Pellegrino winery of Marsala
Claire Calcagno, Independent Scholar
Giulia Boetto, Centre Camille Julien, Aix-Marseille University, CNRS
Grant Cox, Artas Media
Lauren Tidbury, Honor Frost Foundation
Lucy Blue, Honor Frost Foundation
Mateusz Polakowski, University of Southampton
Pat Tanner, 3D Scanning Ireland Ltd/University of Southampton
References
Frost, H. et al., 1981, Lilybaeum (Marsala). The Punic Ship: Final Excavation Report. Notizie degli scavi di antichita, Supplement to Vol. 30 (1976), Serie Ottava. Rome: Accademia Nazionale dei Lincei.
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