Yachting Art Magazine

May 16 2025

Sinking of the Bayesian yacht: what does the MAIB interim investigation report say?

On 19 August 2024, the British pleasure yacht Bayesian capsized near Porticello, on the north coast of Sicily, killing seven people. A combination of human error, extreme weather conditions and technical vulnerabilities led to this tragedy. Actunautique Yachting Art has published the MAIB's interim report, which details the circumstances of the tragedy.

The Bayesian sank at 4:06 a.m., less than a nautical mile from the Italian town of Porticello. The 55.9-metre British-flagged yacht was on a private cruise with 12 passengers and 10 crew members on board. The final port of call was Naples, after a series of stops around the Aeolian Islands and the north coast of Sicily. But during the night of 18 to 19 August, the weather conditions suddenly deteriorated.

According to the initial findings of the Marine Accident Investigation Branch (MAIB) inquiry, an extremely violent storm, associated with a supercell thunderstorm, generated winds of over 70 knots (130 km/h), causing the vessel to capsize rapidly.

Underestimated weather conditions

The Bayesian had weighed anchor to head for a more sheltered anchorage in Porticello. It had dropped anchor east of the harbour breakwater at around 9.24 p.m. At that time, the sea was calm and the winds were light. Storms had been forecast, but their actual intensity did not seem to have been anticipated. The captain had asked to be woken if the wind exceeded 20 knots or if the ship began to drift. At 3:55 a.m., the wind suddenly picked up. Within minutes, the yacht began to drift with the wind abeam.

At 4:00 a.m., the captain was urgently awakened. The chief engineer started the generators and prepared the hydraulic pumps. The crew busied themselves securing the interior of the boat. At the same time, the first effects of the storm were felt. A strong list to starboard suddenly increased. In less than 15 seconds, the Bayesian was listing at 90°.

A chaotic evacuation

The yacht, now listing, began to fill with water through the openings in the deck. The emergency lighting comes on, and injured or disoriented passengers try to get out. Some crew members manage to reach the upper deck; others are trapped in air pockets. Several people, including a child, are evacuated from the deck or through the openings in the wheelhouse.

Passengers improvised flotation devices. At 4:24 a.m., a life raft was finally released and inflated. Several survivors climbed aboard. The chief engineer fired a distress flare, which was spotted by another yacht nearby, the Sir Robert Baden Powell, which dispatched its launch to rescue the shipwrecked passengers. At 4:53 a.m., the first survivors were brought back on board.

Despite an improvised search operation in the darkness, seven people – six passengers and one crew member – perished in the accident. Their bodies were later recovered by Italian rescue services.

An extraordinary storm

According to the analysis commissioned by the MAIB from the British Met Office, the weather on 19 August was marked by the passage of a very unstable low-pressure area. Conditions in the Porticello area were conducive to the formation of supercells, violent storm structures capable of producing downdrafts and marine tornadoes.

Radar data, satellite images and weather reports confirmed that an intense cell had swept through the area at the time of the tragedy, with gusts exceeding 87 knots. Such violence, concentrated over a narrow strip, could have created a situation of sudden imbalance on a stationary vessel.

Structural stability issues

The Bayesian was built in 2008 by Perini Navi under the name Salute. Its stability was in line with the British Large Commercial Yacht Code (LY2) standards, but only under sailing conditions with the centreboard lowered. However, at the time of the sinking, the vessel was at anchor, under engine power, with the centreboard raised. The centre of gravity and wind profile were therefore different.

A study commissioned by the University of Southampton revealed that, in this ‘motoring condition’ configuration, the maximum stability angle (beyond which the vessel can no longer right itself) was reduced to 70.6°. Gusts of over 63 knots across the beam were enough to cause capsizing, even without the effect of the sail. This critical limit was exceeded on the night of 19 August.

Another point of concern is that these stability data were not mentioned in the logbook. Neither the captain nor the crew were therefore aware of the increased risk of capsizing at anchor in these conditions.

An avoidable disaster?

The MAIB emphasises that extreme conditions played a decisive role in the accident, but that the configuration of the Bayesian, combined with a lack of operational information on its stability limits at anchor, contributed to the situation.

The lack of concrete measures to anticipate or prevent evacuation in the face of a serious weather warning also raises questions. The crew reacted quickly, but too late, and in a situation of total emergency.

The investigation is ongoing

The recovery of the wreck by the Italian authorities, which is still pending, will provide further technical details: the position of the centreboard, the volume of cargo on board, the points of flooding, the interior configuration and the condition of the liferafts. This data will be crucial in drawing conclusions about the chances of survival, the effectiveness of the safety equipment and the precise sequence of events.

At the same time, a criminal investigation is underway in Italy, which has limited access to material evidence by British investigators. The MAIB's final report, expected in the coming months, should shed light on structural and operational responsibilities.