The majestic Bayesian superyacht, which foundered last year off Sicily, killing seven people, was likely knocked over by an intense gust of wind and sank within minutes, according to a preliminary investigation by British maritime authorities.

As the storm approached, a young deckhand on watch delayed waking up the captain and instead posted a video of the squall on his social media feed, the investigation found.

The result was a fast-moving catastrophe — just minutes, from when the skipper was roused to the ship going down — in which the storm ripped apart a protective awning on the bridge, pushed the enormous yacht all the way over onto its side and sent passengers and crew members scrambling in the dark for their lives as water began to cascade through the cabins.

“The findings indicate that the extreme wind experienced by Bayesian was sufficient to knock the yacht over,” said Capt. Andrew Moll, the chief inspector of marine accidents for the Marine Accident Investigation Branch, a British agency. “Once the yacht had heeled beyond an angle of 70 degrees, the situation was irrecoverable.”

The report noted that the Bayesian’s signature feature, its gigantic single mast, one of the tallest in the world, increased the vulnerability of the boat capsizing in high winds. The New York Times published similar findings last year in its own investigation of the accident and found that the Bayesian was an outlier. All the other boats in the same series, from the same Italian manufacturer, had two masts instead of one.

The company claimed that when operated properly, the Bayesian was “unsinkable.”

Outside experts who read the government agency’s report also pointed to the mast and said that the overall stability of the boat — from its ballast to its superstructure — was questionable at best.