Rescue teams trying to access the submerged Bayesian yacht could be listening out for a timed banging noise, a senior university lecturer has said.
A maritime diving and wreckage expert also warned the teams would have to make “a big choice” as their efforts intensify.
Bayesian was moored around half-a-mile off the coast of Porticello when it sank at about 5am local time on Monday as the area was hit by a storm.
The Italian Coastguard said the six missing tourists from the incident, including Mike Lynch, are feared to have died with their bodies trapped inside a luxury yacht.
Dr Jean-Baptiste Souppez, who teaches mechanical, biomedical and design engineering at Aston University, said: “A sign the rescuers may be looking for is a banging noise at regular intervals.
“This is common practice on submarines, and was one of the signs the search mission for the Titan submarine was looking for after it went missing last year.”
Dr Souppez added the next 24 hours of the rescue operation were “crucial” and the chance of air pockets forming inside the vessel was “simply impossible to predict”.
Speaking to BBC News about what caused the sinking, Dr Souppez said: “Reports from the survivors were that the sinking happened in a matter of minutes.
“We now have reports from the divers that the vessel is pretty much intact, so that very much hints at extreme winds on a rather large-sized rig, causing the vessel to keel over and then most likely start taking on water, which would then lead to a very fast sinking.”
He said the yacht could tilt further than 90 degrees into the water in very strong winds, causing it to take on “very large amounts of water through a number of the openings”.
Bertrand Sciboz, a maritime diving and wreckage expert at French company Ceres, told BBC News: “I think 50 metres is a limit to dive with a certain category of professional divers, so you will need to dive with some kind of helmet and pipe and [be] connected to the surface for oxygen, and also for speaking and hearing and telling what you see and do.
“It’s always very difficult, and especially with a sailing vessel, because you’ve got rope everywhere, you’ve got a sail which is floating in the current, because we are in the Mediterranean Sea and not in the English Channel.
“But the main thing, you know, it’s the fact that in those kind of conditions, it’s very hard to go inside the wreck, and they will have to have to make a big choice at one moment, of salvaging the whole wreck or rescuing the bodies.”