Maritime archaeologists have been going to great lengths to unearth a Victorian shipwreck and its artefacts, only to bury them again.
It may seem counterintuitive, but Flinders PhD student Debra Shefi says reburial is increasingly being used as a strategy to preserve shipwrecks around the world.
Ms Shefi and two other Flinders postgraduates were among 60 archaeologists and volunteers based on a jack-up barge, which acted as a diving platform and conservation laboratory above the wreck Clarence, an early Australian built wooden coastal trading vessel which foundered off Port Melbourne in 1850. It is thought to be the earliest wreck of a colonial boat in Victorian waters.
Clarence is the focus of the Australian Historic Shipwreck Preservation Project, which is funded by the Australian Research Council and involves universities and research institutions around the country.
As well as contributing to a better understanding of the little-known colonial ship-building industry, the aim of the project was to develop protocols for the rapid recovery, recording and reburial of artefacts from historic shipwrecks. Reburial is a major focus of Ms Shefi’s PhD thesis.
Ms Shefi said reburial is particularly useful in situations where funds are not available to pay for full-scale retrieval, conservation, storage and display of the recovered materials.
Although Australian archaeologists have been reburying wrecks after excavation for years, the practice of managing these sites in situ is growing popular both in Australia and overseas.
Ms Shefi said that Clarence was discovered in the early 1980s, and since that time more of the wreck has been exposed by the action of strong currents, storms and dredging in the area.
Clarence was first surveyed in 1985, and Ms Shefi said that comparison between the current state of the wreck and the original site drawings shows that large parts of the ship’s structure have since been lost, along with the remnants of the wooden deck.
Thanks to the action of wood borers, bacteria and water movement, almost any part of the wreck projecting above the seabed has grossly degraded: “We estimate we’ve lost around 60 per cent of what was there in 1985,” Ms Shefi said.
Reburial to preserve what is left became a high priority.
“Although there’s not the money to fully excavate the site, remove the artefacts and conserve them in a lab, by reburying them we don’t lose as much as we have over the last 25 years,” Ms Shefi said.
“And then if we have the opportunity to go back in the future, we can.”
Artefacts from Clarence included remnants of leather fittings, fragments of porcelain and wooden barrel staves, some very well preserved by the anaerobic effect of burial in sand.
Ms Shefi said the position of the artefacts is recorded before they are retrieved, catalogued and photographed. They are then wrapped in geotextile and shadecloth to slow down degradation, and reburied a metre below the seabed.
In cases where a site is under threat from development, the strategy is to excavate the wreck as thoroughly as possible, and bury artefacts off-site.
Ms Shefi said developing a protocol and national standard for reburial will assist with planned legislation that will bring Australia into line with UNESCO treaties and best international heritage practice.
“It really is revolutionary in the field of maritime archaeology,” Ms Shefi said.