"Bayesian" s/y sinks in Palermo

[Frank Holden]

I’m sure the downflooding angle is impressive, it needs to be as water where such events occur is never flat. The water just slops in by the bathtub full when you’re leaned over far enough for the waves to do their thing. The C32 is good at that stuff, don’t take it the wrong way. I’m more pointing out that the very best designs can still be overcome in the wrong circumstances.

Easy enough to calculate the down flooding angle . Check posts #115 and #157 . The 'outdoor entertainment areas' frd and aft extend almost right to the yacht's side . Simply use half the beam ( 5.7 metres? ) and the freeboard (2 metres?) to find the angle either by construction or by looking up the tangent thingo - Tan Angle = Freeboard/half beam.
This Marinetraffic screen shot is interesting. You can see her coming up from the east, anchoring, dropping back and sitting like a duck in a westerly wind, and then dragging off to the southeast before transmissions ceased.
I reckon that with all that windage frd of midships - three furled headsails plus the mast - her head fell off as she dragged and she presented her beam to the wind.

 

[14K478]

Easy enough to calculate the down flooding angle . Check posts #115 and #157 . The 'outdoor entertainment areas' frd and aft extend almost right to the yacht's side . Simply use half the beam ( 5.7 metres? ) and the freeboard (2 metres?) to find the angle either by construction or by looking up the tangent thingo - Tan Angle = Freeboard/half beam.
This Marinetraffic screen shot is interesting. You can see her coming up from the east, anchoring, dropping back and sitting like a duck in a westerly wind, and then dragging off to the southeast before transmissions ceased.
I reckon that with all that windage frd of midships - three furled headsails plus the mast - her head fell off as she dragged and she presented her beam to the wind.View attachment 181865

Go to the top of the class, Frank!

We still don’t understand why a boat/small ship, under bare poles, is wind heeled to the point of knockdown by a 60 knot wind on the beam, but there may have been more wind where she was than was recorded at the airport.

 

[14K478]

Tragic. The power of nature.....

From the links, as one would expect, a local investigation has started. As the yacht was Brit flagged and has Brits onboard, both criteria for a Marine Accident Investigation Branch enquiry have been met. Either either, or in this case, both. They are super professional and highly regarded. The report will take time but when it is released, the normally publish causes and preventative action to help other vessels.

They do not prosecute. If there is a case of negligence then the MCA enforcement Unit takes responsibility for prosecutions.

This will take time......

It maybe, however, I the interim, survivor statements may be released by the press.

I’d like to clarify a point: the MAIB are not a part of the MCA and do not report to it. Their investigations never lead to action by the MCA Enforcement Unit. The latter carry out their own investigations, quite separately.

 

[Mark-1]

Go to the top of the class, Frank!

We still don’t understand why a boat/small ship, under bare poles, is wind heeled to the point of knockdown by a 60 knot wind on the beam, but there may have been more wind where she was than was recorded at the airport.

It was hit by a waterspout (tornado).

 

[Baggywrinkle]

It was hit by a waterspout (tornado).

... or a microburst. I've been hit by one beam on at anchor in a thunderstorm with a land line ashore .... it came from nowhere, was much stronger than the prevailing wind at the time, and immediately tore the anchor out, the landline was like a bowstring and the boat heeled and swung through almost 90° before the anchor caught some rocks and stopped us. Scared the sh!t out of me and we stopped a few metres from the shore, I thought we had gone aground as when I tried to move the rudder it was jammed, fortunately it was the brake on the wheel and when released all was OK. It was a goood few years ago, but we will now only use a lind-line if the weather is very settled and never if isolated thunderstorms are predicted.

What Is a Microburst and How It Occurs | RainViewer Blog

 

[Chiara’s slave]

It was hit by a waterspout (tornado).

With potential momentary windspeeds of 200knots or so. Hard to imagine a boat that wouldn’t be knocked down.

Frank, I’m not sure if you realised the context of my post you quoted. In any case, the point stands, even the best designs can be caught out by conditions that are just wrong for them, clearly nobody in the design office ever thought that this yacht would be knocked down. I’ll not go so far as to say it was poor, just ‘too big to have that happen’. All it lacked was Leonardo and Kate.

 

[flaming]

... or a microburst.

I think the accounts of broken glass which seem to be from before it turned over suggest that the windows were smashed, and then it capsized. That may well be fairly consistent with being hit by a waterspout.

 

[westernman]

After all it only weighs 500 tonnes.

So 4 bags 6m across would easily do the job.

 

[Fr J Hackett]

I think the accounts of broken glass which seem to be from before it turned over suggest that the windows were smashed, and then it capsized. That may well be fairly consistent with being hit by a waterspout.

The broken glass is most probably from glasses, plates and interior fittings that would not ave been secured.

 

[Mark-1]

I think the accounts of broken glass which seem to be from before it turned over suggest that the windows were smashed, and then it capsized. That may well be fairly consistent with being hit by a waterspout.

Yeah, I saw that. the owners wife escaped over broken glass and got her feet badly cut in the process. Perhaps she was able to escape *because* the windows were out.

...but against that we have been told the windows were intact and the glass was 3cm toughed glass so strong the divers has to get a local engineering firm to make bespoke tools to break it. Surely windows strong enough to resist waves could handle wind of any strength? On that basis I'd come to the hypothesis that the glass was from mirrors or glass coffee tables etc, not from windows. But who knows. Broken windows would certainly explain the sinking.

Of course a grand piano (or somesuch) in freefall would certainly break a window, but then wouldn't it be the 'lower' windows that broke and under those circumstances how would she be walking on the glass and escaping?

I guess we'll have to be patient and wait for more details.

 

[flaming]

The broken glass is most probably from glasses, plates and interior fittings that would not ave been secured.

There's a very interesting interview in Der Spiegel with the captain of the other boat who rescued the crew from the liferaft. In it he recounts what the chief engineer told him. It's paywalled, but has been quoted over on Anarchy.

The really important things seem to be that the capsize took 16 seconds, and from capsized to sunk was under 2 minutes. He also said that there were no open hatches etc.

When you think of the volume of water that has to enter in order to sink a boat this size in under 2 minutes, I think failure of the windows, either being hit by the waterspout or when pushed underwater, is the only real way that could happen.

Imagine being on a luxury cruise on a superyacht. You're asleep in your cabin at 4am with the boat at anchor. All of a sudden you're thrown out of bed and all power is lost. Then water rushes in and you never get out. It really doesn't bear thinking about.

 

[pmagowan]

Very sad and thoughts must be with all the loved ones of those involved. A terrifying and random occurrence.

I think we could all speculate until the cows come home about what happened and what we might learn from this but, I suspect, it comes down to very very bad luck. I, personally, would have no concerns about being on such a boat whether hatches are open or closed etc and would not have any fear of a similar event happening. We can learn from keels falling off, boats foundering in storms and all kinds of situations but the bottom line is if you find yourself in a waterspout, or a volcano or under a falling meteorite it is just bad luck! I, personally would not take any significant preparations for this situation because it just doesn't happen (you are obviously much more likely to win the lottery). Of course, we should all take what reasonable precautions we feel is necessary for bad weather events but if we plan for waterspouts we are probably missing the wood for the trees and our actions are very likely introducing greater and more likely risks.

People were having a good time in a great boat then they weren't. If the MAIB finds anything useful for general consumption, great. You can't engineer out all risk without also engineering out the enjoyment of life.

 

[Fr J Hackett]

There's a very interesting interview in Der Spiegel with the captain of the other boat who rescued the crew from the liferaft. In it he recounts what the chief engineer told him. It's paywalled, but has been quoted over on Anarchy.

The really important things seem to be that the capsize took 16 seconds, and from capsized to sunk was under 2 minutes. He also said that there were no open hatches etc.

When you think of the volume of water that has to enter in order to sink a boat this size in under 2 minutes, I think failure of the windows, either being hit by the waterspout or when pushed underwater, is the only real way that could happen.

Imagine being on a luxury cruise on a superyacht. You're asleep in your cabin at 4am with the boat at anchor. All of a sudden you're thrown out of bed and all power is lost. Then water rushes in and you never get out. It really doesn't bear thinking about.

Eventually the source of the water ingress will be revealed I doubt that it will be hull windows my bet would be on the sliding doors.

 

[flaming]

Eventually the source of the water ingress will be revealed I doubt that it will be hull windows my bet would be on the sliding doors.

Oh, to be fair I am lumping all the "large glass areas" in one category as "windows" when I say something must have failed.

 

[dunedin]

Easy enough to calculate the down flooding angle . Check posts #115 and #157 . The 'outdoor entertainment areas' frd and aft extend almost right to the yacht's side . Simply use half the beam ( 5.7 metres? ) and the freeboard (2 metres?) to find the angle either by construction or by looking up the tangent thingo - Tan Angle = Freeboard/half beam.
This Marinetraffic screen shot is interesting. You can see her coming up from the east, anchoring, dropping back and sitting like a duck in a westerly wind, and then dragging off to the southeast before transmissions ceased.
I reckon that with all that windage frd of midships - three furled headsails plus the mast - her head fell off as she dragged and she presented her beam to the wind.View attachment 181865

Your AIS track confirms what I thought I recalled from the track I saw on the day - the references to keel being up having been into the port seem to be wrong? Hadn’t (yet) entered the port, but arrived from elsewhere and anchored

 

[Mark-1]

He also said that there were no open hatches etc.

How would he know? There will have been people escaping from all over, all sorts of openings could have been left open. Apparently some of the openings are automated, maybe they opened themselves in some way.

I find the broken windows theory very compelling, but against that we've been told the windows were intact and it seems unlikely that the regulations around construction would allow for windows that couldn't stand up to being submerged. It was an ocean going vessel, they'd expect waves to hit the windows mid ocean.

On that basis it seems more likely that there were openings open. Either because that was standard procedure at anchor or in the chaos.

Again, I'm sure a grand piano in free fall would break a window, but that doesn't explain how the wife's feet got cut.

I guess we'll have to wait and see.

 

[chriss999]

The Sky News website quotes the CEO of the ultimate owner of the company that built Bayesian as saying that it was ‘unsinkable’, so the Titanic references are entirely appropriate.

 

[flaming]

How would he know?

He was the engineer, it was his job to know. And I think he was referring to the state of the boat before the weather hit.

 

[Mark-1]

Very sad and thoughts must be with all the loved ones of those involved. A terrifying and random occurrence.

I think we could all speculate until the cows come home about what happened and what we might learn from this but, I suspect, it comes down to very very bad luck. I, personally, would have no concerns about being on such a boat whether hatches are open or closed etc and would not have any fear of a similar event happening. We can learn from keels falling off, boats foundering in storms and all kinds of situations but the bottom line is if you find yourself in a waterspout, or a volcano or under a falling meteorite it is just bad luck! I, personally would not take any significant preparations for this situation because it just doesn't happen (you are obviously much more likely to win the lottery). Of course, we should all take what reasonable precautions we feel is necessary for bad weather events but if we plan for waterspouts we are probably missing the wood for the trees and our actions are very likely introducing greater and more likely risks.

People were having a good time in a great boat then they weren't. If the MAIB finds anything useful for general consumption, great. You can't engineer out all risk without also engineering out the enjoyment of life.

Wise words.

The vessel suffered a freak accident. I'm certain a Prini Navi 56 is more "Tornado Proof" than my house or car and I'm not planning to alter them.

Personally I'm interested in the conjecture, though.

 

[Mark-1]

He was the engineer, it was his job to know. And I think he was referring to the state of the boat before the weather hit.

Sorry, I mistakenly thought you were referring to the captain of the rescuing vessel.

Yeah, that's pretty strong evidence that they intended all openings to be shut.

I guess there could be grand pianos free falling through glass on the lower side and the wife could be wading through broken glass from mirrors/coffee tables/glasses on the upward side.