What Caused the Sinking of the 186-ft Perini Navi ‘Bayesian?’
If you’ve read the Dr. Seuss story Yertle the Turtle, you probably have a pretty good sense of what caused the sinking of the superyacht Bayesian. Yertle the Turtle wanted to sit atop the world on a tower of turtles that would reach the moon. The need to be higher than all others led to his undoing.
The Bayesian is an immense and impressive yacht, but its Achilles heel appears to be the original owner’s desire to have one of the tallest masts in the world. The 186-ft Perini Navi superyacht was one of several of that model built, though the others were ketch rigs. The Bayesian had an immense 237-ft-tall, six-spreader aluminum spar, putting far more weight aloft than on her sisterships.
The storm that sank Bayesian was about as extreme as the yacht’s design, and, beyond the spar, there is a long list of contributing factors. The final report on this disaster won’t be written until the boat is raised and the lawsuits are over, but in the meantime, the New York Times has put together what is the most comprehensive outline to date of all the leading factors. The switch to a sloop rig required ballast adjustments and numerous other follow-on modifications that likely contributed to the disaster. You can read the excellent report here.
Like the owners of the Titanic, the current owners of Perini Navi said Bayesian was unsinkable.
Your. Almost. Close. But. There. Few. Matters. Many. Didn’t. Think. About the. Main. Issue. Lighting. Hit. The. Mast. And. Broke. The left. Side. Rigging. Just. Secs. Before. She. Sank. !
You. Can. Almost. Put. A. Sentence.togeather. A. L. M. O. S. T.
Conjecture ……is a somewhat calculated guess .
Wait for the autopsy report of the boat……………….when up.
Not to mention the severe downflooding risk inherent in the design, due to the very low downflooding angle and the unsecured sliding saloon doors which fell open under their own weight when the boat heeled.
Another factor is the below deck level air intakes for ventilation and engine operation, for the same purpose as old time deck funnels. These open vents were seen by the divers who recovered the bodies. On a warm, calm Mediterranean night, they would have been open and allowed to be open. The sudden extreme squall was the key to starting this horrible sequence. It seems like there were multiple factors for this tragedy that will be thoroughly investigated and modeled
I’m surprised not much is opined about the anchor in this case.
According to the alleged published GPS tracker, the yacht not only dragged its anchor a considerable distance (perhaps into deeper water), but the yacht rotated 180, meaning the bow (where anchor is attached) was facing mainly away from the wind direction.
if this is correct, the likely only way the yacht would have maintained its stern more-or-less into the wind, is if the anchor fouled the keel, and the wind held the yacht against the anchor pivoting at the keel, but not able to rotate, because the pivot point is no longer the bow, but somewhere mid-ships, some 30ft below.
This could explain why the yacht began to tip starboard as the wind increased, with the height of the mast not helping, and waves smashing direct into the stern and into the engine exhaust vents.
Difficult to explain without a diagram, but I’m surprised this has not been discussed… perhaps I’m totally wrong.
The orientation of the yacht is an error in the AIS data based on the direction of the travel. There was no giro data to be with so the AIS assumed it was pointed that way. The Yacht Report did some great reporting on this whole thing.
Assumption is the Mother of all mess ups
Is this really that hard to understand?
I’m only speculating of course, but she had a keel that when extended–as it normally would have been when sailing–gave her a draft of 32 feet. When retracted her draft was a mere 13 feet. That’s an enormous difference in stability between keel up and keel down.
Initial reports said her keel was up, but how far up we don’t know.
Calculating stability is not difficult. If the yacht could sail upwind with a full main and jib–and certainly she could do that–should could withstand an enormous wind with only her mast as windage, assuming the keel was fully down.
The likelihood that her mast was “too tall,” and that’s why she flipped over (as that utterly stupid article in the New York Times claims)–with no sail up–is highly unlikely.
I suggest that her captain probably wanted to anchor as close to shore as he could. It’s better scenery and a shorter ride to the beach that way. No one likes to be anchored way out if they don’t have to. Plus in shallower water you don’t have to put out as much chain to get adequate scope. So he lifted the keel and chose his spot. Probably has done the same routine hundreds of times and never had a problem.
The strength and direction of the wind probably came as a surprise. He wasn’t thinking that a front would arrive suddenly and blast the yacht from the side before she had a chance to swing to her anchor. That doesn’t happen very often.
And with the keel probably mostly up, so that he could anchor where he wanted to be, the wind laid her over, very suddenly. Any sailboat beam to the wind will react accordingly.
Obviously the water came in, and probably the air intakes for the main engines were open (and maybe there was no provision to close them), so probably that was it.
It’s not likely that Ron Holland would have designed the engineroom to flood when the yacht heeled over–he’s a lot smarter than that–but my guess would be that Perini Navi didn’t pay him to work out the details of the engineroom ventilation because they have built plenty of big yachts and think they know how to do it themselves. Unfortunately, they didn’t think it through and put them in below where they should have been. Maybe they were focused more on the aesthetics in choosing the location when they should have been making sure the yacht had watertight integrity in unusual situations?
Almost always in a big catastrophe it’s a combination of things that, had any one of them not been present, it never would have happened.
My guess, and it’s only a guess, is that (1) the keel was too far up so they could anchor where they wanted to be so (2) when a storm front arrived and the wind suddenly came from the beam she laid over far more than she should have, then (3) the water came in quickly through poorly located engineroom ventilation ducts, which (4) further degraded her stability, so (5) instead of coming up she (6) went down.