Bayesian sank

Where do you get this idea about “a tall mast and no keel”? They had a massive keel which in the up position was more than enough to provide stability without sails. The keel bulb which I think I ve seen listed at 40 tons was about 13’ below waterline in the up position.

But, if the boat heeled enough to get some of the watertight doors underwater, its game over.

Note that a couple of weeks ago a 150+’ MY partially sank in Greece when they started getting underway with the side garage open. Look up MY Ethos
 
boatbum said:
Indeed. From what I read dereliction of duty. They were pulled into the party by the gang, and it led to their demise. The crew let them down. Professional? I don't think so.
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Where the heck is this party comment coming from? Party? Gang?
 
From your post Pascal;
"To avoid the shipwreck, the CEO continued, "it was inappropriate to have, as I read, a party. Not that evening. The hull and blanket had to be secured by closing all the doors and doors, after putting the guests in the ship's meeting point as per the emergency procedure. Then turn on the engines and pull up the anchor or unhook it automatically, put the bow in the wind and send the keel down. The next morning they would start at zero damage." He remarked that "mistakes have been made." And he added: "Between the arrival of a storm and the boarding of water there is a world. A number of activities had to be done to avoid being in that situation. I as commander of the ship would have moved, but even if for some reason I had to stay there, I would have managed those weather conditions which then, let's face it, were not so crazy. After all, the commander of Sir Robert, next door, managed to manage everything without any problems."
 
It was 4 am!!! I really doubt there was a party going on and if anything most of the crew would have been up and working. Not caught by surprise.
 
PascalG said:
Where do you get this idea about “a tall mast and no keel”? They had a massive keel which in the up position was more than enough to provide stability without sails. The keel bulb which I think I ve seen listed at 40 tons was about 13’ below waterline in the up position.

But, if the boat heeled enough to get some of the watertight doors underwater, its game over.

Note that a couple of weeks ago a 150+’ MY partially sank in Greece when they started getting underway with the side garage open. Look up MY Ethos
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A heavy keel cannot compensate for the long period heel caused by a tall mast. Statically yes, the keel can compensate, dynamically not so much. There is no doubt in my mind that the vessel was not batten down for weather so openings likely played a role, as did the failure to properly position the vessel for move it to different waters.

All vehicles have stability problems, some more than others. The question comes, how do you the operator deal with weak stability? The early 707s had real problems with dutch roll and once it got started because it was a failure of dynamic stability, you could easily lose the entire airplane. There came a point in which specific training was required for crews to deal with this problem. This boat with it's tall mast and long period roll had problems which required extra care of the operator. The question comes, how much care was taken? Why did other boats around it survive and it did not? What did their crews do different?
 
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The stability of larger boats is calculated, verified etc just like what you are used to with airliners. There is one major difference though: money is no object with super yachts unlike the nickel and diming, cost conscious, penny saving, crum scrounging airline industry.

Whoever commissioned the original “Bayesian” didn’t care if it was going to cost a few millions more to be sure the boat was safe.

You can’t apply the cattle carrying airline industry mind set to the super yacht world.

Now where I will concede the super yacht world is lagging behind is crew training, CRM, etc.

Some reports mentioned then 51 yo captain had 8 years experience as a superyacht captain. If true, here is the issue
 
PascalG said:
It was 4 am!!! I really doubt there was a party going on and if anything most of the crew would have been up and working. Not caught by surprise.
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Unless they were all out like the lights or hung over. This is either incompetence or lack of leadership/teamwork.
 
PascalG said:
The stability of larger boats is calculated, verified etc just like what you are used to with airliners. There is one major difference though: money is no object with super yachts unlike the nickel and diming, cost conscious, penny saving, crum scrounging airline industry.

Whoever commissioned the original “Bayesian” didn’t care if it was going to cost a few millions more to be sure the boat was safe.

You can’t apply the cattle carrying airline industry mind set to the super yacht world.

Now where I will concede the super yacht world is lagging behind is crew training, CRM, etc.

Some reports mentioned then 51 yo captain had 8 years experience as a superyacht captain. If true, here is the issue
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I was not comparing it to the airline industry. The 707 design originated not as an airliner but as a military transport and tanker to replace the KC-97, known as the KC-135. The conversion of that design to a commercial aircraft was in fact, the last iteration of the original design. Lots of KC-135s were built before the 707 and a few were lost to dutch roll. In the marine industry like the aircraft industry static stability is easily and readily calculated. What is more difficult is dynamic stability. A stability of a given vessel is often calculated then verified by placing ballast then calculating how that ballast affects the vessel. It is simple weight and arm calculation. What is not calculated is what happens when that ballast is swayed say to starboard, swings back to port then swings back to starboard. How much inertia is imparted, how much remains? How quickly does the amplitude diminish? That depends on a lot of factors including the period of displacement, hull buoyancy, keel and chine shape (which affects yaw during displacement and thus return to normal hull buoyancy). None of those things can be known without an actual and very sophisticated wave tank test of a scale model. Even then, model tests like wind tunnel test often miss things that adverse conditions spawn. Like the ATR series of aircraft during icing (One of the reasons why calculated icing tests are no longer allowed, real icing is required testing on a real vehicle). The design of this boat stretched the known with among the tallest masts in the world coupled to a sloop design (which fundamentally lacks a chine). I would like to think there was some serious investigation into its dynamics but I am guessing as a "one off" not so much.

Now scab onto weak design dynamics to a weak crew and yeah, you got a recipe for disaster. This will not be a single point failure because that rarely causes an accident. This is a chain of events both human and design, which led to the loss of vessel and life.
 
boatbum said:
Unless they were all out like the lights or hung over. This is either incompetence or lack of leadership/teamwork.
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Without guests it would a possibility but not with guests on board as no captain would allow his crew (or himself) to be partying and drinking.

Human error? Absolutely like leaving watertight doors open and possibly failure to monitor the weather
 
local Italian prosecutors have a history of stretching their 15 seconds of fame to the max. The worst example being how a local prosecutor brought manslaughter charges against the Williams F1 team principal and chief designer following the death of Ayrton Senna back in 94. The case dragged on for years and years before finally being dismissed even though it was clearly a racing accident.

What door or hatch was left open will be interesting. Since the boat sand by the bow, it is unlikely that it was the stern beach club or the side garage. Both being in a watertight compartment which would have prevented the boat from sinking

Most likely, a forward hatch or side door caused water to flood in and the question will be why was it left unsecured…. Did a guest or crew left it open?

During the press conference today, authorities said all 6 bodies were found in port side staterooms, the high side as the boat is resting on its stbd side. 4 or 5 of them were in the same SR indicating people trapped inside moved up to the port side as the boat flooded.
 
Transportation accidents are not treated the same in other countries as they are in the United States. In most cases around the world, when someone dies in a transportation accident it is considered a criminal act until proven not. That is why US pilots are advised to leave the foreign country when involved in a fatal accident. I had a friend who had a mid-air when a single Cessna bounced off the landing gear of his 727 into Guadalajara. After landing, he bought tickets for the entire crew and left for LAX. Good thing he did. They tried to indict him not because he was at fault, but because he survived.

I'm guessing this is why the designers and builders are so vocal right now. They're worried about criminal charges.

If I was the investigators I would certainly get an acolyte of Dr. Ted Fujita to assess exactly what weather occurred. I'm guessing a pretty strong micro burst that maybe even broke the mast and helped with instability or simply rolled the boat beyond recovery or held it in period beyond recovery. Open hatches sealed the deal.
 
Today investigators suggest it was a downburst or microburst, not a waterspout.

They also stated that no drug or alcohol testing was done on the crew which I find odd.

A broken mast would have improved stability but divers said the vessel is intact.
 
PascalG said:
Today investigators suggest it was a downburst or microburst, not a waterspout.

They also stated that no drug or alcohol testing was done on the crew which I find odd.

A broken mast would have improved stability but divers said the vessel is intact.
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Only if the mast clears the boat. A broken mast at a half point can heel the boat since it weighs the boat down off centerline especially if the boat has heeled then the mast snaps. Since the boat is intact, it is not a factor here. Fujita was the world's foremost expert on downbursts which is why I suggested to get one of his acolytes on the investigation.
 
This article says the mast snapped. Which is it?

www.yahoo.com

Billionaire Yacht Was Piloted Recklessly Before Deadly Sinking, Its Builder Warns

Blame Game The builder of the sunken superyacht owned by British billionaire Mike Lynch, who died with six others after the vessel went down earlier this week, is blaming "an endless chain of errors" for the maritime disaster. Flying under a British flag, the 184 foot yacht, the Bayesian, was...
www.yahoo.com www.yahoo.com
 
Another misleading headline and article…. “Piloted recklessly”? It sounds like the boat was pushed hard and to the limit. Not the case. Did the crew fail to prepare? It looks like it.

The CEO makes some avoid points about some of the things that should have been done, but for instance you re not going get guests out of bed at 4 am and muster in the salon for a typical summer thunderstorm… if you were to do that, guest would be up every night…

I guess now that all the bodies have been recovered, more focus will be placed on the condition of the boat. Divers said the vessel is “intact” which implies the mast is still in one piece. They re going to start a thorough inspection this week with divers and ROVs. Going to be interesting
 
It will be interesting. I'm not sure what "intact" means. Just the hull, hull and rigging? Who knows.
 
Agree. Although if the last was broken, you d think the divers would have mentioned it.

other important questions… is the anchor still attached to the chain… is the tender in the bow storage… are the bow storage hatches closed… hopefully details will come Out soon
 
Some additional insights. One is particularly damning. Not exactly unsinkable according to one.

"Seventy-three degrees? There you go. The heeling arm would have again been above the righting arm at about 2/3 of that angle and, without sheets to ease or ability to steer, she would have been committed to capsize around 50 degrees of heel. Vessels without sails set will also exhibit dynamic heeling, according to Wolfson Unit wind tunnel test which would reduce the wind force necessary to capsize by roughly half. No mystery here. About the same range of stability as the first Pride of Baltimore."

loosecannon.substack.com

Yacht Design Experts Dissect How an 'Act of God' Sank Bayesian

Chris Freer, Tad Roberts, Roger Long
loosecannon.substack.com loosecannon.substack.com
 
boatbum said:
Some additional insights. One is particularly damning. Not exactly unsinkable according to one.

"Seventy-three degrees? There you go. The heeling arm would have again been above the righting arm at about 2/3 of that angle and, without sheets to ease or ability to steer, she would have been committed to capsize around 50 degrees of heel. Vessels without sails set will also exhibit dynamic heeling, according to Wolfson Unit wind tunnel test which would reduce the wind force necessary to capsize by roughly half. No mystery here. About the same range of stability as the first Pride of Baltimore."

loosecannon.substack.com

Yacht Design Experts Dissect How an 'Act of God' Sank Bayesian

Chris Freer, Tad Roberts, Roger Long
loosecannon.substack.com loosecannon.substack.com
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From your cite. "Vessels without sails set will also exhibit dynamic heeling, according to Wolfson Unit wind tunnel test which would reduce the wind force necessary to capsize by roughly half. "

As I said earlier in this thread, "I suspect there is going to be a finding that there is a big difference between static stability and dynamic stability."
 
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