The former captain of the luxury superyacht that sank off the coast of Sicily killing seven people has shared his own notes on the tragedy, claiming it would have required “extreme circumstances” for the “sound and seaworthy” vessel to capsize.

Stephen Edwards, who skippered the Bayesian from 2015 to 2020, took to LinkedIn to share his thoughts, focusing on the design of the yacht and noting that he wished to avoid “contributing to the wild speculation” around the sinking.

James Cutfield, the 51-year-old New Zealander who was captain of the vessel when it sank, has so far declined to answer questions from Italian prosecutors.

A key point raised by Edwards was the “downflooding angle” of the Bayesian, or the angle at which water would begin to enter through the engine room and vents in the cabins when the vessel was heeled (tipped or leaned) to one side.

Edwards said this angle was around 40-45 degrees, much less than the Angle of Vanishing Stability (AVS) which is the angle at which the boat can no longer return to upright.

The AVS would be 90 degrees with the keel lowered and 75 degrees with it raised, he said.

He said the Bayesian would be in “serious trouble” if flooding could not be controlled once it reached the “downflooding angle”.

A local Facebook page shared a picture of the yacht Bayesian at anchor before sinking near Palermo. Photo / via Facebook, Fabio La Bianca

Edwards also said he was “100%” sure the hull door, located on the port side aft, would not have been left open at night, writing that it was only ever opened in flat-calm conditions.

He said there were no other opening windows or portholes and the only other openings are on or close to the centre of the boat, meaning the Bayesian would have had to be tipped beyond the “downflooding angle” and already flooding through the vents.

“The vessel Bayesian was sound and seaworthy by design, and to my knowledge well maintained as such,” Edwards wrote.

“However, heeling her to more than around 45 degrees while in normal operational state could result in flooding and subsequent loss if the flooding could not be controlled.

“The weather conditions that could have created these extreme circumstances can indeed occur with very little warning and being so localised are difficult to prepare for, leaving a very short time for the crew to react.

“How the vessel came to be taken outside her operation limits is what the investigators will need to determine, which I’m sure they will,” he concluded.

‘Understandably exhausted’

Skipper James Cutfield is under investigation by Italian authorities alongside other crew members, but is yet to answer prosecutors’ questions.

Aldo Mordiglia, one of his two lawyers, told the Telegraph there were “two reasons” for the skipper’s decision not to respond to questions.

“He is understandably exhausted. In addition, we were only appointed as his lawyers on Monday and we need to gather information, which we do not have yet, in order to prepare the defence.”

Investigators previously announced it was plausible that crimes of multiple manslaughter and causing a shipwreck through negligence had been committed, despite the yacht being hit with a very sudden meteorological event.

‘We didn’t see it coming’

James Cutfield’s brother said he is a “well-respected” captain who has worked on boats his whole life.

Immediately after the sinking, Cutfield told Italian media of the abrupt nature of the water spout that made a death trap out of the superyacht.

“We just didn’t see it coming,” he said.

New Zealand citizen James Cutfield, 51, was the captain of the Bayesian, the boat that sunk off the coast of Italy.

Cutfield’s brother Mark told the Herald his brother was a “very good sailor” and was “very well respected” in the Mediterranean.

James had been a captain on luxury yachts for eight years and had previously been working on them and involved in building them for the past 30 years in various locations around the Mediterranean.

He said before he worked for the British tech tycoon Mike Lynch, he had worked for a Turkish billionaire.

Mark said James was a “top sailor” in his youth and raced 470s competitively.