Italian special forces divers have embarked on an operation to recover video surveillance equipment which could explain why Mike Lynch’s superyacht sank.

The sinking of the Bayesian off the coast of Sicily last month led to seven deaths, including that of the British tech tycoon and his teenage daughter.

The challenging task has been assigned to specialist divers from a navy special forces unit called Comsubin, the equivalent to Britain’s Special Boat Service and which normally specialises in underwater sabotage and coastal raids.

The divers are venturing down to the wreck, which lies 165ft beneath the sea, about half a mile off the fishing town of Porticello on the north coast of Sicily.

Investigators hope that if they can be recovered intact, the surveillance cameras and other equipment will help them find out what happened on the night the Bayesian sank during a violent storm.

It is believed the luxury yacht was hit by a meteorological phenomenon known as a downburst, which can pack as much punch as a mini tornado.

Aside from Lynch and his 18-year-old daughter Hannah, the other victims of the Aug 19 tragedy were Recaldo Thomas, the ship’s Antiguan chef, Jonathan Bloomer, the chairman of Morgan Stanley International, his wife Judy Bloomer, Chris Morvillo, a lawyer at Clifford Chance, and his wife Neda Morvillo.

Fifteen people survived the sinking, including James Cutfield, the captain from New Zealand. After being questioned by investigators in Sicily, he returned to the home he shares with his wife in Majorca. He is under investigation for possible charges of multiple manslaughter and causing a deadly shipwreck but has not been charged. 

Tim Parker Eaton and Matthew Griffiths, the two British crew members also under investigation, have not been charged either. 

Under the Italian legal system, being placed under investigation does not imply guilt and does not necessarily mean that charges will be brought.

Prosecutors investigating the tragedy are determined to raise the wreck of the Bayesian and bring it to shore.

The objective is “to find out elements of the situation which led to the sinking”, said Raffaele Macauda, an admiral in the Italian coast guard who is involved in the enquiry. The navy divers’ inspection of the wreck “will help us draw up a plan to recover the yacht”, he said.

The operation to lift the yacht from the seabed will require a team of divers, a leading salvage expert said.

Nick Sloane, the South African salvage master who raised the Costa Concordia cruise ship after it rammed into an island off the coast of Tuscany in 2012, told The Telegraph the divers would have to remove the vessel’s mast and rigging, empty thousands of litres of fuel from its tanks, and then connect rigging from the wreck to a barge equipped with cranes on the surface of the sea. The divers would work with underwater robots known as ROVs (remotely operated vehicles).

Once on the barge, the yacht will then be brought to a port and investigated for clues as to what went wrong.

Tracking data from on board the yacht suggests there was a 16-minute window between it being hit by the storm and sinking.

Although the incident is under investigation, the head of the company that built the yacht reiterated allegations that the sinking must have been caused by a chain of human errors.

“From the analysis of the terrible 16 minutes of that night we maintain that the water must have entered from open hatches,” said Giovanni Costantino, the chief executive of Italian Sea Group, which owns Perini Navi, the company that built the Bayesian.

“We maintain the actions that you would expect from a crew were not taken. They should have prepared the vessel, closing all the hatches. It was unsinkable. If water had not entered, there would not have been any problems. The storm that was coming was clearly visible. It is significant that the local fishermen read the situation and decided not to go out to sea.

“The water must have started to enter from the stern and the stability was compromised.”

Seven people died “probably because the crew was not coordinated, they were not properly prepared, they were distracted and not ready to intervene”, Mr Costantino told an Italian television channel. “They didn’t follow the correct procedures and seven people remained trapped below.”