Mike Lynch is a celebrated technology sector entrepreneur, sometimes referred to as the UK's answer to Bill Gates
Mike Lynch is a celebrated technology sector entrepreneur, sometimes referred to as the UK's answer to Bill Gates AFP

Divers and an underwater drone searched Tuesday for six people, including a British tech tycoon and international banker, believed trapped when a luxury yacht sank off Sicily.

The 56-metre (185 feet) yacht "Bayesian" was anchored with 10 crew and 12 passengers on board when it was struck by a waterspout mini-tornado, before dawn on Monday.

Fifteen people, including a woman and her one-year-old baby, were rescued. The body of one man -- reported to be the yacht's chef -- was found.

Among the six missing were UK tech entrepreneur Mike Lynch and his 18-year-old daughter Hannah, and Jonathan Bloomer, the chair of Morgan Stanley International, and his wife Judy.

The passengers were guests of Lynch -- sometimes referred to as Britain's Bill Gates -- to celebrate his acquittal in a massive US fraud case.

While Italy's coastguard said the search continued without a break, Captain Vincenzo Zagarola said it was "difficult to imagine" it would end well.

Experts and officials have described the sinking as an "extroardinary" event.

The search was made difficult by the British-flagged yacht lying largely intact on the seabed some 50 metres down.

Divers take one minute to get down and another minute to get back. They are restricted to 12 minutes for each dive because of the water pressure, according to fire service spokesman Luca Cari.

Lynch's wife Angela Bacares was among those rescued, according to Salvo Cocina, head of Sicily's Civil Protection Agency.

As well as Bloomer, who testified for Lynch in the US case, the missing included Lynch's lawyer Christopher Morvillo, and his wife Neda, according to law firm Clifford Chance.

Lynch, 59, was acquitted on all charges in a San Francisco court in June after he was accused of an $11 billion fraud linked to the sale of his software firm Autonomy to Hewlett-Packard.

It emerged Tuesday that a co-defendant, former Autonomy executive Stephen Chamberlain, died after being hit by a car on Saturday in England.

Divers trained to work in tight spaces were flown in from Rome and Sardinia late Monday.

A first, nighttime search of the wreck failed, with firefighters saying early Tuesday that furniture was blocking their way.

Marco Tilotta, from the Palermo fire service divers' unit, told AFP search efforts were concentrated on getting inside the sleeping and living areas of the yacht.

"The spaces inside the boat are very tight and if you encounter an obstacle it is very complicated to move forward, just as it is very difficult to find alternative routes," said Cari, from the fire service.

The vessel was moored off Porticello, east of Palermo, when violent winds and rains suddenly swept up the coast.

"It was terrible. The boat was hit by really strong wind, and shortly after it went down," survivor Charlotte Golunski told ANSA news agency.

Golunski, board director at Luminance, a company founded by Lynch, lost hold of her one-year-old daughter in the waves "for two seconds", before grabbing her again.

"Lots of people were screaming" in the dark, said Golunski, who scrambled onto a life raft.

Reportedly owned by Lynch's family, "Bayesian" was built by Italian shipbuilding firm Perini Navi in 2008. Its 75-metre mast was the world's tallest aluminium sailing mast, according to the Charter World website.

A waterspout is a column that descends from a cloud to form a rotating mixture of wind and water, often during severe thunderstorms.

Matthew Schanck, from the Maritime Search and Rescue Council, told AFP it was an "extraordinary event".

"This is a large, luxurious superyacht that has founded quite quickly in a touristy, well-known sailing area off Sicily. It's pretty unprecedented."

Karsten Borner, captain of a yacht anchored nearby at the time of the storm, said there was a "very strong hurricane gust" and he battled to keep his vessel steady.

Borner saw the yacht's mast "bend and then snap", according to Italy's Corriere della Sera daily.

Italian authorities have opened a probe, while the UK's marine accident investigation branch sent four inspectors to Palermo.

The 56-metre (180-foot) long luxury vessel was moored off Porticello, east of Palermo
The 56-metre (180-foot) long luxury vessel was moored off Porticello, east of Palermo AFP
Firefighter divers trained to work in tight spaces were flown in from other parts of Italy to search the vessel.
Firefighter divers trained to work in tight spaces were flown in from other parts of Italy to search the vessel AFP