BAYESIAN TRAGEDY: Important Revelations in MAIB Report

May 17/2025:  NO! The near simultaneous accidental deaths of accused fraudsters and tech moguls Mike Lynch and Stephen Chamberlain—in disparate locations, of disparate causes—was NOT the product of an evil corporate revenge plot. It was purely coincidence. We established as much in my previous post on the sudden sinking of Lynch’s superyacht Bayesian while at anchor off Sicily last August 19. We are left with more pedestrian questions concerning exactly why the 183-foot sloop Bayesian foundered so quickly, which are addressed in the interim report just released by Great Britain’s Marine Accident Investigation Branch.

I urge you to read the report for yourselves. Or, if you are post-literate (as so many are these days) you can watch this very apt summary on the Yacht Report YouTube channel:

Early speculation as to the cause of the tragedy rotated around allegations of gross crew negligence (the view of Bayesian’s builder) or poor vessel stability (what most rational people wondered about). It turns out, predictably enough, it was a bit of both.

The most surprising thing I learned reading the MAIB report is that sailing superyachts are in fact inherently much less stable than the normal sailboats we commoners schlep around in. In the superyacht universe, it is evidently common and technically permissible for vessels to have an Angle of Vanishing Stability of less than 90 degrees. As in: your boat will become incapable of righting itself before its mast is in the water. Meanwhile, most cruising and racing sailboats (multihulls excluded) usually have AVS values well past 90 degrees. As in: your mast can be very underwater, and your boat will still right itself. (For a thorough and enlightening discussion of vessel stability and how it is quantified you can check this previous WaveTrain post right here.)

According to Bayesian’s officially approved stability booklet, her AVS in a sailing condition—sails up, centerboard down—was between 84.3 degrees and 92.3 degrees, depending on how much stuff was onboard. The stability booklet, however, did not provide any info on Bayesian’s stability with respect to wind heeling when idle or motoring, with sails down and centerboard up. The MAIB, per its report, commissioned the Wolfson Unit at the University of Southampton, to study that question, based on all available data, and the Wolfson folks concluded Bayesian’s AVS when anchored that fateful night off Porticello, Sicily, was something like 70.6 degrees, due largely due to her enormous aluminum mast (the tallest alloy spar in the world). They also estimated gusting winds greater than 63.4 knots would capsize the boat. This potential vulnerability, the MAIB report notes, was not known to the skipper or crew.

The report’s description of the crew’s activities is less surprising, but of course more dramatic. The skipper expected some thunder squalls and ordered the deck hands standing watch that night to get him up when the wind exceeded 20 knots, or if the boat dragged anchor. The deck hand (identified only as DH2) on the second watch, starting at 0100 hours, failed to do this. At 0300 he saw the approaching thunderstorm. By 0355 the wind was up to 30 knots, and the deck hand had posted a video of the advancing storm online. He also ran around closing hatches and cockpit windows, noted the boat had started dragging anchor, and finally, at 0400, went to wake the skipper.

It’s hard not to feel sorry for the poor skipper. He was roused at 0400. At 0406, Bayesian was hit by a 70-knot gust and her mast was in the water. She down-flooded and started sinking immediately thereafter. The crew made a valiant effort to get the boat up and running in those six minutes, but it turns out on a superyacht you don’t just press a button and start your engine. To get underway, the chief engineer had to start up three generators, plus steering pumps and hydraulic pumps.

Again, you should read the report (or watch the viddy) if you want the whole detailed timeline as to exactly who did what when and how the survivors got free of the boat and were rescued.

The MAIB carefully notes this report is only interim and facts may change as the vessel is salvaged and Italian authorities conclude their investigations, which may result in criminal charges. But I suspect we won’t see any major changes to this narrative.

The lessons learned, as I see them:

a) If you want a really safe sailboat, don’t get a superyacht.

b) If you are at anchor or motoring with sails down on a superyacht, always put your centerboard down if you expect bad weather. Stability booklets for these boats should definitely include info on wind-heeling stability when idle or motoring! Almost certainly, Bayesian would not have been lost if her board was down.

c) Always get the skipper up sooner rather than later.

Meanwhile, the tragedy of Bayesian continues to cost lives. In addition to the owner Mike Lynch, the five guests, and one crew member who were lost when the boat sank, one diver was recently lost while helping to salvage the wreck.

So far no details on how exactly the diver, 39-year-old Rob Huijben, died, but it may have been an explosion from a hydrogen torch. He and other divers reportedly were trying to remove Bayesian‘s boom at the time.