McCartney said the salvage barge photographed near Singapore last year appeared to be equipped with a large crane and a 5-ton "drop chisel," which is designed to cut a shipwreck apart.
"What they're doing is just dropping it down on the wreck, chopping the wreck into manageable pieces, and then using that crane to haul it on board," he said.
Similar equipment was used by some Dutch salvage operators in recent years to remove especially valuable metals, like brass, from British shipwrecks that were sunk at the Battle of Jutland in the North Sea in 1916, McCartney said.
Although researchers have identified and documented the salvage firms responsible for much of the damage to the Jutland wrecks, so far the Dutch authorities have taken no action, he said.
Eyes in the sky
Radio beacons and satellite radar technology now make it possible to track salvage ships in the same way that many fishing trawlers are now tracked to prevent illegal fishing, McCartney said. Salvage ships that are seen to linger over known shipwrecks, or that exhibit other suspicious behavior, can be flagged automatically and inspected when they reach port, he said.