Museum veteran carefully conserving shipwreck treasures

Shipwrecks may capture the imagination, but the job of retrieving what is left behind from reefs, rocky coastlines and the seabed beneath wild oceans is painstaking and at times challenging.

Western Australian Museum conservator Jon Carpenter, who has dived on ship and aircraft wrecks around Australia and overseas, said safely delivering the historic pieces to shore required meticulous planning and careful packing.

Mr Carpenter has worked at the museum since 1974 and gave a presentation to senior school students as part of the Western Australian Marine Science Institution’s Thinking Blue outreach program.

Some of the objects he’s helped recover and conserve are displayed at the WA Shipwrecks Museum in Fremantle. These include a cast iron cannon from Australia’s earliest shipwreck, Trial (wrecked in 1622) and a wrought iron anchor from the Zuytdorp (1712). Other objects, now located at the Museum of Tropical Queensland, are a silver pocket watch and pistol from HMS Pandora (1791).

“Objects that we recover from the ocean have absorbed water and incorporated salts and have been altered by it,” Mr Carpenter said.

“It is important that they are kept in wet storage, to prevent damage due to drying, corrosion and crystallization of salts,” he said.

“If an organic object such as one made of waterlogged wood dries out before impregnation or consolidation treatment it will irreversibly shrink, crack and distort.”

To avoid the potential for osmotic shock, ceramic objects recovered from the sea are initially soaked in seawater diluted with freshwater, and eventually desalinated completely in freshwater.

“Legislation protects underwater archaeological sites so you cannot indiscriminately recover material. You must also know how to conserve it properly,” he said.

On a wreck site, buried objects are uncovered using an airlift or water dredge which operate like an underwater vacuum cleaner. It is safer to expose an object by using a hand to fan the sand to mobilize it and allow the vacuum to carry it away.

Mr Carpenter said the material a vessel was made of, the location where it sank and the prevailing environment on the seafloor all affect how well it is preserved more than the time it’s spent underwater.

“When a ship is buried, and the environment is stable it is usually conducive to preservation and that is why the remains of many shipwrecks are more than 2,000 years old,” Mr Carpenter said.

Dozens of ships have been wrecked along Western Australia’s coast and include Batavia (1629), the Vergulde Draeck or Gilt Dragon (1656), Zeewijk (1727), Xantho (1872) and Omeo (1905).

“When you uncover personal belongings like the watch from HMS Pandora, it is a reminder that people were on board and may have lost their lives.”

The Zuytdorp, wrecked near present day Kalbarri, is the only Dutch East India Company ship to have run into the coast of the Australian mainland rather than on a reef or island.

Mr Carpenter said ships wreck because they are in the wrong place either by human error or by loss of control. Working these sometimes dangerous locations can also pose challenges to marine archaeologists and conservators centuries later.

Diving on the Zuytdorp, at the base of coastal cliffs, was one area where the diving team had to be aware of the risks and take particular caution.

Mr Carpenter said while the objects have been recovered from many shipwrecks and after conservation displayed in museums some wrecks such as HMAS Sydney II are designated war graves and will remain untouched.

Jon Carpenter’s presentation: Shipwreck to Showcase is available to view on WAMSI’s YouTube channel.