By Sharon Kennedy - ABC
Why it's not feasible to raise Bunbury's whaling wrecks ?
Digging up a wreck is the easy part, says Ross Anderson from the WA Museum. A marine archaeologist, Ross was part of the successful dig late last year which uncovered wrecks near Koombana Bay.
"It's the physical raising and the conservation of the material, for the long term, that's really difficult and expensive.
"We're still learning lessons here with the Batavia."
The archaeologists work closely with department of materials at the Museum to conserve shipwreck artefacts, says Ross.
"There is a whole field of study called waterlogged organics. Skin and bone and wood survives well but as soon as you take it out of that environment, they dry out and they can disintegrate really quickly.
"So it's a specialised area. What has been done with the Batavia and the Mary Rose is that they are treated with polyethylene glycol, a water soluble wax. As the wood dries out and all of those cellular spaces in the wood dry, it's replaced.
"You can see it on your hair conditioner."
Treating a ship would need a few tonnes of PEG, says Ross and a specially constructed framework in which to immerse it. "It would take at least ten years...and then you'd have to dry it out under controlled conditions.
"The cost of something like that is estimated to be something like $5-6m. Then you've got the long term storage and curation of it."