Inside the tragic sinking of a tech mogul’s $40M superyacht off Sicily

In August, a $40 million superyacht named the Bayesian set sail off the coast of Sicily. Its owner, billionaire tech mogul Mike Lynch, was celebrating a new lease on life with family and friends after winning a yearslong legal battle.

But triumph turned to tragedy early on Aug. 19, when the luxury vessel sank in the Mediterranean Sea. Lynch was among the missing.

The 59-year-old was known as the British Bill Gates.

"I think it's more Steve Jobs," Reid Weingarten, who defended Lynch in court, told ABC News' Juju Chang, noting that some considered Lynch "the grandfather of AI" who "completely changed the world with his brilliance."

His first job involved mopping floors, but the math savant soon moved up in the world.

"He earned whatever he got, " Weingarten said. "And then, you know, went to Cambridge, and just by dint of his intelligence succeeded."

Lynch's big break came in 1996, when he launched software company Autonomy, a pioneer in artificial intelligence. He rose quickly in the ranks of British society, becoming an adviser to then-British Prime Minister David Cameron and hosting members of the royal family at Autonomy’s headquarters.

In 2011, Lynch sold Autonomy to U.S. tech giant Hewlett-Packard for $11 billion. The company later sued Lynch, alleging that he had inflated Autonomy's value by billions of dollars prior to the sale.

The lawsuit kicked off a saga that consumed the next decade of Lynch's life. He was extradited to the U.S., where he was put under house arrest and faced the possibility of dying in prison. In a turn of events, a San Francisco jury unanimously acquitted Lynch this past June.

He and his wife Angela were also the proud parents of two daughters. Lynch was eager to see 18-year-old Hannah as she prepared to attend Oxford University in the fall.

Sunday Times journalist Danny Fortson interviewed Lynch after the verdict, and told ABC News that being a father "meant a lot" to the businessman.

"He got really animated when he started talking about his daughters, and kind of this idea of making up for lost time," he said. "And clearly this yacht trip was about that."

Fortson’s interview with Lynch took place weeks before the tech mogul died.

Lynch spoke about embracing his freedom in a podcast interview with Fortson.

"And so now it's very strange. You have a new life," he said in July. "And that comes to the question you're asking me, which is what do you want to do with your new life?"

Lynch planned to celebrate his legal victory aboard his beloved boat, with those closest to him. It was a beautiful day when Lynch, Angela, Hannah, nine guests and 10 crew members boarded the superyacht the Bayesian from the coast of Italy, on Aug. 18.

Among the guests were Chris Morvillo, a friend of Lynch and a member of his legal team, and his wife Neda. The New York couple’s daughters were planning to meet them in Greece after the Bayesian’s tour ended.

The Bayesian’s aluminum mast was among the tallest in the world, standing at around 240 feet in the air.

"The mast looked like the Empire State Building in the middle of a sailboat," Weingarten said. "It was huge."

Family friend Susannah Gurdon lives near the Lynches in Suffolk, England, and vacationed with them several times.

"It was just thrilling," Gurdon told ABC News of her past trips on the Baynesian. "It was like one of those old ships you can imagine from, you know, from history and this giant boat, as you build up speed, there's some wind, you know, you're tilting on one side."

She noted that Lynch urged anyone who came on board to prioritize safety.

"One of the first things he does when you're a guest on his boat is, you're given a talk about safety. And he totally prioritized and respected the captain," Gurdon said. "He made it very clear, no wandering about on the deck in the night and things."

After several days of sailing on the Mediterranean, the trip was coming to an end. Sunday, Aug. 18, was the last full day of the trip, with guests planning to leave the yacht the following afternoon. While the vessel was at anchor in the bay near Porticello, a storm barreled through early the next morning.

Tracking data revealed how the Bayesian struggled at 3:50 a.m., with the winds seeming to send the superyacht zigzagging out of control. CCTV imagery showed the mast’s lights disappearing in the storm, and after 4:06 a.m. location data for the Bayesian cut out. The superyacht was fully submerged.

Within 16 minutes of being struck by what investigators believe was a downburst -- a strong downward wind system that gushes outward -- with winds of at least 60 mph, the Bayesian sank by the stern before tilting on its right side and plummeting onto the seabed.

Elizabeth Smith, a research meteorologist with the National Severe Storms Laboratory at NOAA (National Oceanic and Atmospheric Administration), told ABC News that downburst winds are often mistaken for tornadoes.

"They can be quite severe and quite scary if you don't know what's going on," she said. "The really destructive phase of a downburst is incredibly short. That's going to be when the initial strong winds arrive. And that will only last for a minute or so."

The 22 people on board had to act quickly in the brief window of time before the Bayesian went under. Sailor Matthew Griffiths, who was on watch at the time of the sinking, told Italian authorities that he "woke the captain up when the wind was blowing at 20 knots" and that "he ordered to wake everyone else up," according to Italian news service ANSA.

Griffiths noted the superyacht "tilted and we fell into the water … we were then able to climb back on and we tried to rescue those we could," ANSA reported. He also said "we were walking on the walls" of the vessel.

Some of the people on board had to cling to a life raft after the Bayesian capsized. They were rescued by a nearby vessel, captained by Karsten Borner.

"After the storm was over, we noticed that the ship behind us was gone," Borner told Reuters. "And then we saw a red flare so my first mate and I went to the position and we found this life raft drifting, 15 people inside."

Among the survivors were nine crew members and six passengers, including Mike Lynch's wife Angela.

Lawyer Ayla Ronald and her partner Matthew Fletcher barely made it off, according to attorney Reid Weingarten.

"Ayla, I'm told she made it by ... seconds," he told ABC News. "I mean she was the last one up on the deck."

Also among the survivors was Lynch's colleague Charlotte Golunski, who was tossed into the sea along with her 1-year-old daughter.

"I kept her afloat with all my strength, my arms raised so she wouldn’t drown," she told Italian newspaper la Repubblica. "It was all dark, I couldn’t keep my eyes open. I screamed for help, but I could only hear the screams of others."

Dr. Domenico Cipolla treated 1-year-old at the hospital, and told ABC News how close Golunski came to losing her to the sea.

"She momentarily lost hold of her daughter, who was carried off by the current," he said in Italian. "After 2 or 3 seconds, she was able to recover her."

Golunski's partner survived as well.

However, six passengers and one crew member were still missing -- Mike and Hannah Lynch among them.

Search and rescue teams descended on the scene, recovering the body of Recaldo Thomas, the ship's cook, near the wreckage.

Specialist divers had to go so deep that they could only stay under for about 12 minutes at a time, traversing through furniture and objects blocking access to cabins.

The bodies of the six missing passengers were all found in cabins on the left side of the ship. This area was closest to the surface, where air bubbles would have been concentrated, investigators noted.

Mike Lynch's body was found with the bodies of lawyer Chris Morvillo, his wife Neda Morvillo, Morgan Stanley executive Jonathan Bloomer and his wife Judy Bloomer in one room.

Hannah's body was the last recovered, discovered alone in a separate cabin.

Autopsy reports showed that some of those who died had no water in their lungs, according to Reuters.

"They found an air pocket, they didn't drown," journalist Danny Fortson told ABC News. "So that they were, you know, 100 feet down, 150 feet down, in the dark, in the cold, with just, you know, with a dwindling supply of oxygen."

Greg Morvillo is haunted by the fates of his brother Chris and sister-in-law Neda.

"I think about the last few moments for them, on the ship all the time. It's haunting, it's terrifying," he told ABC News. "And I cannot imagine what they were going through. I can't imagine how it felt or what they knew. It is impossible to wrap my mind around, but I can't stop thinking about it."

The investigation into the cause of the sinking is ongoing, as are efforts to recover the ship from the bottom of the sea.

"Was there a problem with the design of the ship?" Morvillo said. "People have speculated. I don't know the answer to that."

ABC News Studios' "IMPACT x Nightline: Gone in 16 Minutes: Sinking of the Superyacht" streams on Hulu beginning Thursday, Nov. 14.

ABC News' Aicha El Hammar and Phoebe Natanson contributed to this report.