"Bayesian" s/y sinks in Palermo

[Mister E]

If a direct hit front the water spout with its hight wind speed the air would have been sucked out of the boat. If the boat is on its side then water would be sucked in.
This type of thing is seen in tornados.

 

[Binnacle]

Personally I'm enjoying the conjecture, though.

"Enjoying" ? You might care to qualify that word given the loss of lives..

 

[Poignard]

...

 

[billskip]

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.

For water to get in air has to get out, the speed of flooding indicates to me the boat did not fully capsize (it couldn't the mast hit the bottom and stopped it) which would mean inrush of water and outrush of air had to be permitted while she was on her beam well passed the recovery angle, there is also the possibility that the mast got trapped on the bottom and held the boat at an angle..
My guess is the difference between a bad situation and tragically total loss was because the keel was up.

 

[Binnacle]

If a direct hit front the water spout with its hight wind speed the air would have been sucked out of the boat. If the boat is on its side then water would be sucked in.
This type of thing is seen in tornados.

Would you like to describe the process in detail, giving verified examples of air pressure in the core of a waterspout to cause "suction" of the air from the vessel, and some calculations (even a rough estimate) of the speed of the waterspout passing over the vessel, and how many cu metres/sec might be "sucked" from the sea into a vessel on her beam ends ?

 

[Chiara’s slave]

Would the keel stay down with the boat heading for inverted? Even ‘unballasted’ I’ll be betting it’s very heavy. Our board mechanism is designed to knock up on impact, and, I have no doubt, if inverted would not stay in the down position. Clearly our boat has almost nothing in common with this behomoth, just curious if there’s a slight similarity there.

 

[Mark-1]

"Enjoying" ? You might care to qualify that word given the loss of lives..

Corrected.

 

[flaming]

For water to get in air has to get out, the speed of flooding indicates to me the boat did not fully capsize (it couldn't the mast hit the bottom and stopped it) which would mean inrush of water and outrush of air had to be permitted while she was on her beam well passed the recovery angle, there is also the possibility that the mast got trapped on the bottom and held the boat at an angle..
My guess is the difference between a bad situation and tragically total loss was because the keel was up.

Unless the AVS was less than 90, I don't think there's any way any sailing boat could go beyond 90 by wind action alone, no matter how strong. If she's held flat by the wind and water does not come in, then she pops up when the wind reduces. Hell of an experience and likely some injuries on board, but doesn't sink the boat.

I am assuming that the AVS for this sort of boat is greater than 90.... But I don't know...

 

[Chiara’s slave]

Unless the AVS was less than 90, I don't think there's any way any sailing boat could go beyond 90 by wind action alone, no matter how strong. If she's held flat by the wind and water does not come in, then she pops up when the wind reduces. Hell of an experience and likely some injuries on board, but doesn't sink the boat.

I am assuming that the AVS for this sort of boat is greater than 90.... But I don't know...

The colossal draught, even board up, would lead you to believe that, AVS wise, she could survive a knock down.

 

[Mark-1]

.

 

[Fr J Hackett]

This video at about 5' 50" shows similar winds flipping a catamaran and laying over a 50M yacht in New Zealand. The video is a bit rambling but for those that question the ability of a strong wind to push a 56M yacht on to its beam ends it will answer the question. It is perfectly possible.

 

[dunedin]

…….

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.

Surely on a sailing vessel that is designed to be sailed fast, the grand pianos etc would be secured so they don’t slide about as the boat heels?

 

[Portofino]

My guess is the difference between a bad situation and tragically total loss was because the keel was up.

I ll second this ^ .
Adding the water entered from the patio doors either breaking or inadvertently being open at the wrong time .

Further more all previous testing , class malarkey, engineering, computer sims , safety sign off etc for heeling and indeed a knockdown were based on a secure rear beach club orifice AND keel down , obviously any other hatches closed .

There’s a vid circulation in from NZ a few yrs ago of a catamaran tipped up in a storm and subsequently sinking .
Behind it in the foreground there is a yacht [ a sister ship ] to Baysian , which is knocked down and immediately uprights .
They knew the storm was coming and secured / battened down the boat it survived.

So the builders have evidence to support they are unsinkable. But only if the crew prepare it .

There’s talk of the tender not stowed and the bow tender garage partially left open .Apparently some one went ashore and returned very late around midnight…..but this is a usual SY activity.

 

[Mark-1]

Surely on a sailing vessel that is designed to be sailed fast, the grand pianos etc would be secured so they don’t slide about as the boat heels?

It's been reported that there was loads of loose furniture and that yes, it did all slide around.

Having said that I'm questioning that a little. I wonder if there are actually rules about the weight of loose stuff and actually there was very little, but still enough to be reported as a hindrance.

 

[Portofino]

This video at about 5' 50" shows similar winds flipping a catamaran and laying over a 50M yacht in New Zealand. The video is a bit rambling but for those that question the ability of a strong wind to push a 56M yacht on to its beam ends it will answer the question. It is perfectly possible.

You beat me to it .
The pivot pin wear leading to a rattling plate within the body is a good spot .As to why they tend to retract them at anchor .
We had a Gibsea 7.6 in the 80 s with a lifting keel and indeed it was a swinging plate which rattled when down @ anchor .

 

[RunAgroundHard]

Just for information, Bayesian yacht information

https://www.perininavi.it/wp-content/uploads/2018/05/bayesian-formerly-salute_brochure.pdf
https://www.perininavi.it/yacht/2008-bayesian-formerly-salute/

ABS Brochure for Yacht Notation https://ww2.eagle.org/content/dam/eagle/publications/brochures/Yachts.pdf
Bayesian Notation ABS, (Maltese Cross), A1, AMS Yachting Service + MCA

These notations indicate that the:

• material for hull construction is tested/certified in accordance with the applicable ABS Rules and Guides
  and that the construction of the hull is carried out under ABS survey (ÀA1)
• ship’s machinery and equipment have been constructed and installed in accordance with the
  requirements of the ABS Rules (ÀAMS)

When built, the boat was assessed by ABS, later she was flagged to the UK and the MCA would have reviewed ABS documents to establish if they were materially equivalent to MCA acceptable standards for class.

MCA Code for Super Yachts https://assets.publishing.service.gov.uk/media/5a81a95aed915d74e33ff69c/LY3_-_Final_Version.pdf

Quote from Stability Section 11 (Damage Stability, Section 11.3)

Objective: This section outlines the minimum requirements for intact and damage stability. For vessels less than 85m Load Line length, a minor damage methodology is adopted in which damage is assumed not to occur on any bulkhead, deck, or other watertight boundary.

I don't know what the current coding is, or if she was still in code, highly likely that she would as insurance is dependant on that.

 

[Mister E]

Would you like to describe the process in detail, giving verified examples of air pressure in the core of a waterspout to cause "suction" of the air from the vessel, and some calculations (even a rough estimate) of the speed of the waterspout passing over the vessel, and how many cu metres/sec might be "sucked" from the sea into a vessel on her beam ends ?

I have no idea apart from reporting of tornadoes apart from seeing things sucked into the air on TV reports.

 

[E39mad]

You beat me to it .
The pivot pin wear leading to a rattling plate within the body is a good spot .As to why they tend to retract them at anchor .
We had a Gibsea 7.6 in the 80 s with a lifting keel and indeed it was a swinging plate which rattled when down @ anchor .

The centreplate in a boat that size is so heavy it is almost impossible to rattle. They don't rattle in Southerly's where the keels are ballasted but weigh nothing like the board/keel in a 56m yacht.

 

[Sea Change]

The centreplate in a boat that size is so heavy it is almost impossible to rattle. They don't rattle in Southerly's where the keels are ballasted but weigh nothing like the board/keel in a 56m yacht.

The bronze centreboard in our 33ft boat clonked and thumped about a lot unless hard on the wind. So we generally raised it at anchor. It was very heavy, certainly counted as ballasted.
I'd like to think that a superyacht would have better engineering tolerances though.

 

[Wandering Star]

I ll second this ^ .
Adding the water entered from the patio doors either breaking or inadvertently being open at the wrong time .

I’m not really wanting to speculate on this thread because it’s such a tragic event but I’ve mentioned a couple of times on other threads my experience of delivering a catamaran from Croatia to St Lucia. There were two identical cats being delivered at the same time and we both had the same experience where the sliding “patio” style doors jumped off the runners more than once in bouncy conditions. I’m guessing Bayesian's build quality would be somewhat higher than those cats but nevertheless ….