Rescue teams in Porticello, Sicily, returned to the site of a storm-sunken superyacht Tuesday to search for six people, including British tech magnate Mike Lynch. Fifteen of the 22 people aboard survived. Italian Firefighters via AP, HO PORTICELLO, Sicily — Police divers resumed searching Tuesday for six people believed trapped in the hull of a superyacht that sank in deep seas off Sicily, including British tech magnate Mike Lynch, who was celebrating his recent acquittal on fraud charges with the people who had defended him at trial.

The luxury sailboat, off Porticello near Palermo, was some 164 feet underwater – far deeper than most recreational divers are certified for and a depth that requires special precautions. Recovery crews could only stay for 12-minute shifts, a measure that slowed efforts to reach the cramped inside of the wreck. Divers tag-teamed the shifts and were using a remote-controlled underwater vehicle, or ROV, to help in the search.

They hadn’t been able to access the below-deck cabins because they were blocked by furniture that shifted during the violent storm that struck the vessel early Monday. Rescue crews said they assume the missing six are in those cabins because the storm struck when most would be sleeping, but the teams haven’t verified their presence there through portholes. The Bayesian, a 184-foot British-flagged yacht, was moored about a a half-mile offshore when a storm rolled in before 4 a.

m. Monday. Civil protection officials said .