Why are there two investigations into Bayesian – and could they reach different conclusions?

Nearly two years after the 56-metre Perini Navi sailing yacht Bayesian sank, one of the biggest questions surrounding the disaster remains unresolved: what actually caused the yacht to sink? So, why are there two investigations, what are they actually trying to determine, and why might they not produce the same answer? 

The tragedy, which occurred off the coast of Porticello, Sicily, on 19 August 2024, claimed the lives of seven people, including British technology entrepreneur Mike Lynch and his daughter Hannah. Since then, the disaster has prompted multiple investigations, a complex salvage operation and intense scrutiny from both the maritime industry and the wider public. BOAT has reported extensively on the sinking, covering everything from the salvage to the investigations in its live blog, as well as an insight into how the tragedy affected the industry one year on (2025).

Recent developments have only added to the confusion. While reports from Italy suggest prosecutors' experts are focusing on crew actions and operational decisions, a UK safety investigation has highlighted previously unidentified vulnerabilities in the yacht's stability characteristics when exposed to extreme winds.

So why do two separate investigations appear to be examining the same casualty – and could they ultimately arrive at different conclusions?

Why are there two investigations?

The existence of parallel investigations stems from Bayesian's unique circumstances. Although the yacht sank in Italian waters, she was registered under the UK flag. That means both British and Italian authorities have legitimate interests in determining what happened.

In Italy, prosecutors in Sicily have been conducting a criminal investigation into the sinking, examining whether any individuals or organisations could bear legal responsibility for the deaths and loss of the yacht. At the same time, the UK's Marine Accident Investigation Branch (MAIB) launched its own investigation because Bayesian was a UK-flagged vessel. While both inquiries are examining the same event, their objectives are fundamentally different.

What is the MAIB investigating?

Unlike prosecutors, the MAIB is not tasked with establishing criminal liability or assigning blame. An MAIB spokesperson told BOAT International: "The MAIB investigation into the foundering of Bayesian is ongoing, and the final report will be published once it is complete and the relevant people and organisations have been consulted on its content."

The agency also pointed to the legislation governing its investigations, which states that the purpose of a safety investigation is the prevention of future accidents through the identification of their causes and circumstances. The legislation further specifies that it is not the purpose of an MAIB investigation "to determine liability" or "to apportion blame".

According to the MAIB, this separation is deliberate. Safety investigations are conducted independently from criminal or enforcement proceedings, allowing witnesses and participants to provide information freely without fear that their evidence will be used against them in legal proceedings.

In practice, this means the MAIB is seeking to understand what happened and identify lessons for the wider maritime industry rather than determine who, if anyone, is responsible.

What has the MAIB found so far?

In May 2025, the MAIB published an interim report that provided the first detailed insight into its findings. Drawing on analysis commissioned from the UK Met Office and the University of Southampton, the report suggested that Bayesian may have been vulnerable to extreme wind conditions when operating in a particular configuration.

Researchers concluded that wind speeds above 63.4 knots striking the yacht broadside could have resulted in capsize if the vessel was in a "motoring condition" with her centreboard raised and sails stowed. Once the yacht exceeded a heel angle of 70.6 degrees, recovery would have been impossible, according to the study.

Crucially, the report concluded that the stability information available to the crew did not identify this operating limitation. Large yachts carry approved stability information that provides operators with guidance on the vessel's stability characteristics and operating limitations under different loading and operating conditions.

What are Italian prosecutors investigating?

The Italian inquiry has a very different purpose. Rather than focusing solely on safety lessons, prosecutors are examining whether criminal offences may have been committed. The investigation has reportedly considered allegations including negligent shipwreck and manslaughter.

Several crew members have  been placed under investigation. This is a procedural step in the Italian legal system that allows prosecutors to continue gathering evidence and does not imply guilt. 

In April this year, Italian media reported that meteorologists appointed by the prosecutors had concluded the weather was not severe enough to be the sole cause of the yacht sinking. The prosecutors declined to comment on the leak.  

The recovery of the wreck has been viewed as a crucial stage in the Italian investigation. Following the completion of the salvage operation, Italian authorities have taken possession of the yacht for forensic examination, with the hull expected to provide important evidentiary material as the inquiry continues.

Could the Italian criminal investigation conclude before the MAIB publishes its final report?

While the two investigations are legally independent, it remains unclear which will conclude first. The MAIB has emphasised that safety investigations are conducted separately from criminal investigations and enforcement proceedings. The two processes serve different purposes and operate under different legal frameworks.

Both investigation have indicated that examination of the recovered wreck will form an important part of their investigation. Now that Bayesian has been raised from the seabed and transported ashore, forensic examinations are expected to continue.

Whether the Italian investigation reaches its conclusions before the MAIB publishes its final report therefore remains uncertain. Likewise, there is currently no public timeline for the publication of the MAIB's final report, beyond the agency's statement that it will be released once the investigation is complete and relevant parties have been consulted on its contents.

Could the investigations reach different conclusions?

Potentially, yes. That does not necessarily mean one investigation is right and the other is wrong.

A safety investigator may conclude that the incident was caused by a combination of design vulnerabilities, environmental conditions and human factors. A criminal prosecutor, meanwhile, must determine whether specific individuals or organisations acted negligently or unlawfully. Those are related questions, but they are not identical.

As Bayesian undergoes forensic examination in Italy and both investigations continue, the maritime industry may eventually receive multiple answers to the same question – one focused on preventing future accidents, and another focused on legal responsibility.