Specialist Italian divers on Tuesday launched a fresh search for six people, including UK tech tycoon Mike Lynch and his teenage daughter, missing since their yacht capsized off Sicily.
The British-flagged Bayesian, which had 22 people aboard including 10 crew, was anchored some 700 metres from port before dawn Monday when it was struck by a waterspout, a sort of mini tornado.
Lynch's wife Angela Bacares was among 15 people rescued, but the businessman and his 18-year-old daughter Hannah were missing, Salvo Cocina, head of the Civil Protection Agency in Sicily, told AFP.
Firefighter divers trained to work in tight spaces were flown in from Rome and Sardinia late Monday, but a first search of the wreck some 50 metres below the sea surface failed.
"Access was limited only to the bridge, with difficulty due to the presence of furniture obstructing passage", the firesfighers said on X.
The 56-metre (180-foot) long luxury 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," a British survivor named as Charlotte Golunski told ANSA news agency.
Golunski lost hold of her one-year-old daughter in the waves "for two seconds", before managing to grab her "while the sea raged", she said.
"Lots of people were screaming" in the dark, said Golunski, who managed to get on a life raft.
A waterspout is a column that descends from a cloud to form a rotating mixture of wind and water over a body of water, often during severe thunderstorms.
Just a few hours later, the seas were calm as divers recovered a body, reported to be the yacht's chef.
They also spotted a body inside the sunken vessel, a source close to the recovery operation said.
Lynch, 59, is a celebrated technology sector entrepreneur and investor, sometimes referred to as the UK's answer to Bill Gates.
Most of those aboard were British, and the passengers were guests of Lynch, celebrating his recent acquittal in a massive fraud case, according to Italian media.
Lynch was acquitted on all charges in a San Francisco court in early June after he was accused of an $11 billion fraud linked to the sale of his software firm Autonomy to Hewlett-Packard.
The Bayesian was a superyacht built by the Italian shipbuilding firm Perini Navi in 2008 which boasted a 75-metre mast, the tallest aluminium sailing mast in the world, according to the Charter World website.
A photograph posted on social media Monday by the Baia Santa Nicolicchia bar in Porticello showed the yacht all lit up, its towering mast shining in the darkness, just a few hours before the storm hit.
Karsten Borner, the captain of another yacht anchored nearby at the time of the storm, said there was a "very strong hurricane gust" and he had to battle to keep his vessel steady.
He saw the Bayesian's mast "bend and then snap", according to Italy's Corriere della Sera daily.
Italian authorities have opened a probe into the incident.
