Did Bayesian superyacht’s 237ft mast cause it to sink?

Wind could have toppled aluminium structure, leaving hull to take on water

Bayesian’s 237ft metal mast may have played a part in the sinking of the superyacht off the coast of Sicily, experts have suggested.
The yacht, named after the mathematical theory Mike Lynch used to make his millions in the tech industry, foundered in the small hours of Monday morning.
Key among potential reasons for the loss of the vessel will be its most striking feature – the aluminium mast.
Four British personnel from the Marine Accident Investigation Branch are on their way to Palermo to carry out a preliminary assessment.
There are also theories that hot overnight temperatures of 27C (80C) could have prompted passengers to leave portholes and windows open – hastening the sinking when the high winds hit.
Launched in 2008 by Perini Navi, Bayesian is one of the 50 largest sailing yachts in the world and her mammoth mast supported a total sail area of almost 32,000 sq ft.
Bayesian had the tallest aluminium mast in the world when it first took to the seas under her former name Salute. The record was overtaken last year when Jeff Bezos, the Amazon billionaire launched his yacht, Koru.
Koru’s masts stretch to 278ft tall according to Boat International magazine.
Tom Sharpe, a former Royal Navy commander and warship captain, said initial reports from survivors and witnesses suggested “that the weather was sufficiently violent to cause her to capsize at anchor”.
Weather reports from Palermo airport, 12 miles west of the yacht, suggest that at about 4am, winds switched from a gentle south-westerly breeze to gusts of 40mph, with temperatures dropping.
Local newspapers have described the weather as a tornado and a waterspout, which is a tornado above water.
The pressure of high winds on the mast could have helped tip the boat over in rough seas, experts have suggested.
Mr Sharpe said capsizing seemed “unlikely” to him given the Bayesian’s size “and that boats like that are designed to survive poor weather – unless something failed at the same time like a valve that let water in and made the whole boat unstable”.
He said it was more likely that the Bayesian had “dragged anchor”. Anchors are designed to lodge on rocks on the seabed, but if the seabed is too soft, or weather is so bad that the anchor is dislodged, then a boat can drag its anchor and drift.
If a boat drifts into an obstruction such as a rock or another boat, this can damage the boat by tearing a hole in its side leading to sinking, Mr Sharpe suggested.
The sea bed off Porticello, the Silician harbour nearest to where Bayesian was moored for the night, consists of a mixture of rocky and muddy areas, according to nautical charts reviewed by The Telegraph.
This means the yacht could have dragged anchor if it had been lowered into a soft, muddy patch of seabed.
A captain of another boat anchored nearby said his vessel was hit by abnormally strong winds on Monday morning.
Karsten Borner said the Sir Robert BP was battered by strong gusts in the early hours of the morning but he managed to stabilise the vessel while anchored by using the engine.
He said as they were doing this, they noticed the Bayesian nearby and manoeuvred to avoid hitting it.
“We managed to keep the ship in position, and after the storm was over, we noticed that the ship behind us was gone,” said Capt Borner.
Mr Sharpe said: “From a seamanship point of view, the other boat (Sir Robert BP) coming up on her main engines and using those to keep position around [her own] anchor is what you should do. Yacht anchors are often not that robust and that is the best way to avoid putting too much strain on it and/or dragging.”
An alternative theory is that the weight of the mast led the Bayesian to capsize.
A yacht industry source told The Times that the vessel sank after the weight of her mast took the hull beyond its “down-flooding angle” – the point at which a boat cannot right itself after swinging at a steep angle – meaning water rushed over the sides into the interior.
“The wind toppled the mast, which fell over the side, causing the boat to heel over and take on water, capsize and sink very quickly,” the source said.
This can occur whether the mast snapped off or not.
Sam Jefferson, editor of Sailing Today, told The Telegraph: “She has a very tall, aluminium mast – I believe it is the second tallest aluminium mast in the world – and that would not have helped.
“Many yachts with big masts have carbon masts instead of aluminium as these save on weight and improve stability and performance.
“Stability was obviously the problem in the extremely strong winds she was experiencing and I’d assume the boat was pinned on its side and could not right before it filled up with water.”
Another superyacht expert who asked not to be named told The Telegraph that the mast could have pulled the Bayesian over into capsizing, although he expressed some scepticism, saying sailing yachts are designed to prevent that from happening.
He said the anchor-dragging theory was also a plausible explanation for why the Bayesian sank.
Typically, crews try to anchor in safe spots that are sheltered away from the wind, they said.
The Bayesian was moored just off Porticello, a few miles east of Palermo. Prevailing winds from the north-east may have robbed the vessel of the shelter offered by the Sicilian coast, which lay to the west.
Dr Lynch was reportedly aboard the vessel. His wife, Angela Bacares, is among those rescued but six others, including four Britons, are still missing.
One person, reportedly the yacht’s chef, died in the incident and his body was recovered by rescuers.
The Bayesian’s last refit was in 2020.
The vessel was listed for rent for up to €195,000 (£166,000) a week, according to online charter websites.
The interior featured six cabins – one master, three doubles and two twin rooms – for up to a dozen guests, with the crew occupying separate quarters.
Fitted out in a Japanese style, the interior was styled by the Remi Tessler design house.
Under her former name Salute, the yacht won the Best Exterior prize at the World Superyacht Awards in 2009, and the Best Interior at the International Superyacht Society Awards in 2008.
A coastguard statement issued on Monday morning said the missing passengers were of “British, American and Canadian nationality”.
Camper & Nicholsons, managers of the Bayesian, confirmed the vessel sank at about 4.30am following “severe weather”.
The Italian Coast Guard is leading search and rescue operations, and said on Monday it had safely recovered 15 individuals.