More than 180 feet long, with a mast towering about 240 feet and a keel that could be lowered for greater stability, the Bayesian luxury yacht did not, in the eyes of its maker, have the vulnerabilities of a ship that would easily sink.

“It drives me insane,” Giovanni Costantino, the chief executive of the Italian Sea Group, which in 2022 bought the company that made the ship, said after its wreck last week. “Following all the proper procedures, that boat is unsinkable.”

But the $40 million sailing yacht sank within minutes and with fatal results: seven dead, including the British technology billionaire Michael Lynch, his teenage daughter, four of Mr. Lynch’s friends and a member of the crew. Fifteen people, including the captain, escaped on a lifeboat.

Mr. Lynch had invited family, friends and part of his legal team on a cruise in the Mediterranean to celebrate his acquittal in June of fraud charges tied to the sale of his company to the tech giant Hewlett-Packard.

The Italian authorities have opened a manslaughter investigation, searching for answers from the survivors, the manufacturer and the wreck itself. They face a range of questions and possible factors.

An ‘earthquake’ in the sky?

When the Bayesian sank around 4 a.m. on Aug. 19, the waters in its area, about half a mile off the Sicilian port of Porticello, were transformed by an extremely sudden and violent storm, according to fishermen, a captain in the area and meteorologists.