One man died and six people were missing, including British tech entrepreneur Mike Lynch, after a luxury yacht was struck by an unexpectedly violent storm and sank off the Sicilian capital Palermo early on Monday, APA reports citing Reuters.
The 56-metre-long (184-ft) sailboat was identified as the British-registered Bayesian and sank with 22 people on board shortly before sunrise, the Italian coast guard said in a statement.
The names of the dead and missing were not immediately released, but a person familiar with the rescue operation confirmed that Lynch was not accounted for. The Italian coast guard said the missing had British, American and Canadian nationality.
The 15 people rescued included a one-year-old child.
"The wind was very strong. Bad weather was expected, but not of this magnitude," a coast guard official in Palermo told Reuters.
Storms and heavy rainfall have swept down Italy in recent days - with floods and landslides causing major damage in the north of the country - after weeks of scorching heat.
Eight of those rescued were transferred to local hospitals. All were in stable condition, local media reported.
The captain of a nearby boat told Reuters that when the storm hit he had turned the engine on to keep control of the vessel and avoid a collision with the Bayesian.
Lynch, aged 59, is known as Britain's Bill Gates and is one of the country's best-known tech entrepreneurs.
He was acquitted in June by a jury in San Francisco of fraud charges linked to the sale of his software company, Autonomy, to Hewlett-Packard for $11 billion in 2011.
He said at the time that he was "elated" to be cleared in the criminal trial in which he denied any wrongdoing and blamed HP for botching the integration of the two companies.
The coast guard said divers were inspecting the wreck, at a depth of 49 metres.
Prosecutors in the nearby town of Termini Imerese have opened an investigation to look into what had gone wrong.