‘We didn’t see it coming’: the tumultuous Sicilian night that took down the Bayesian

The 12 holidaying passengers had come from the UK, the US, Canada, New Zealand and Ireland, occupying six luxurious suites of Bayesian, a 56-metre-long superyacht boasting the tallest aluminium mast in the world. Among the 10 crew members were people from Sri Lanka.

The award-winning, British-flagged vessel, which was built in 2008 by the Italian shipbuilder Perini and managed by Camper & Nicholsons, left the calm blue waters of the Sicilian port of Milazzo on 14 August, sailing for a few days around the Aeolian Islands and off the historic coastal village of Cefalù.

But as storms and heavy rainfall swept across Italy, breaking a long heatwave, the dream holiday turned into a nightmare. The boat sank off the coast of Porticello, a fishing village close to Palermo, after the area was struck by a violent tornado while the passengers were sleeping. The boat’s anchor was down and strong winds caused it to lose balance, which is believed to have caused it to sink.

As of Monday afternoon, one man, reported by the Italian media to be a chef from Canada, was confirmed to have died and six were missing, including the British tech entrepreneur Mike Lynch and his 18-year-old daughter. A source within the rescue team told the Guardian that the passengers were mostly employees or associates of Lynch, known as the “British Bill Gates” and who is believed to have been the owner of Bayesian. He was the co-founder of the software firm Autonomy and in June this year was cleared of all charges at a trial in the US on the 15 counts of fraud he had faced over the $11.1bn purchase of the company by Hewlett-Packard in 2011. His wife, Angela Bacares, was among the 15 passengers rescued, as was a one-year-old child, Sophie, who was taken to hospital in Palermo.

Related: Who is Mike Lynch, the UK tech boss missing in superyacht sinking?

Sophie’s mother, Charlotte Golunski, 36, dramatically recounted how she fought to save her child from drowning in the dark and raging Mediterranean while hearing the piercing screams of fellow passengers. “For two seconds I lost the baby in the sea, then I immediately held her again in the fury of the waves,” she told Giornale di Sicilia. “I held her tightly, tightly to me, while the sea was raging. So many were screaming. Fortunately, the lifeboat inflated and 11 of us managed to get on it.”

Golunski, an Oxford graduate who works for Invoke Capital, a company co-founded by Lynch, told Corriere della Sera she had left London with a group of nine people, including her husband, James Emslie, who was also among those rescued, and Sophie. She said they were all “colleagues and collaborators” of the high-tech software firm. “We were all guests on our boss’s yacht, a kind, extraordinary person who maybe they have not yet saved,” she added. Golunski described a “wonderful, large boat” that had visited the Aeolian Islands, Milazzo and Cefalù before the journey was disrupted by bad weather.

According to La Repubblica newspaper, Bacares, who is in the emergency unit of Termini Imerese hospital in Palermo province, told doctors the boat began to tilt at 4am. Both she and her husband were awakened by the incident. Bacares then climbed up to assess the situation, but the vessel suddenly started to capsize.

One witness described Bayesian as “a beautiful boat, where there had been a party”. “A normal holiday spent happy at sea turned into a tragedy,” the witness told Ansa news agency.

James Catfield, the captain of the yacht who is also at the Termini Imerese emergency unit, told La Repubblica: “We didn’t see it coming.”

The tornado struck suddenly. Karsten Borner, the captain of a boat nearby that rescued some of the survivors, 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.

“We managed to keep the ship in position and after the storm was over, we noticed that the ship behind us was gone,” Borner said, adding that the other boat “went flat on the water, and then down”. He said his crew then found some of the survivors on a life raft and took them onboard before the coast guard picked them up.

Fabio La Bianca, the manager of the Baia Santa Nicolicchia restaurant in Porticello, described how he witnessed the tragedy unfold in front of him. He took a photo of the moored Bayesian, its tall, distinctive mast lighting up the port, at 10pm on Sunday. He wrote on Facebook on Monday morning, before the death of one of the passengers was confirmed: “The yacht on the left sank at 4:05am, hit head-on by the hurricane 300 meters from the port of Porticello, next to another sailboat that provided assistance. There are reportedly 22 people on board, but unfortunately seven are missing, feared trapped inside the hull. An absurd tragedy last night. I am at a loss for words.”

A video clip of the tornado wreaking havoc on an area of beach was also shared on the restaurant’s Facebook page alongside the message: “In an instant the hurricane took everything!”

Pietro Asciutto, a fisher in Porticello, also watched the tragedy unfold. He told Ansa: “I was at home when the tornado hit. I immediately closed all the windows. Then I saw the boat, it had only one mast, it was very big. I saw it suddenly sink.” He added that shortly afterwards he went to the bay of Santa Nicolicchia. “The boat was still floating and then it suddenly disappeared. I saw it sink with my own eyes.”

Specialist divers arrived from mainland Italy on Monday morning as hopes of finding those still missing began to fade. The coastguard said the wreck of Bayesian was lying at a depth of 49 metres.

Prosecutors in the nearby town of Termini Imerese have opened an investigation.

According to shipspotting.com, Bayesian is owned by a firm called Revtom Limited. Lynch’s wife, Bacares, was named as the sole shareholder of the firm, Reuters reported, adding that Lynch’s PhD thesis and the software that made his fortune was based on Bayesian theory.