#Bayesian

[arctic-hands]

I'm having a hard time mustering up sympathy for the type of people who died on one of the world's largest superyachts

[avalonishere]

[malbecmusings]

Even before al the bodies have been recovered, the blame game is in full swing over Perini Navi's 55m Bayesian that went down in a storm off Porticello, Sicily. I read this morning the chief of the group that owns Perini Navi came out swinging, putting the blame squarely on the crew.

There's a good technical analysis from designer Chris Feers below the cut.

TL;Don't want to read: Monohulls of all stripes are designed to survive a knockdown; Perini's engineering is some of he best in the world. Bayesian had a retractable keel which could shorten her 32' draft to 12'. With the keel extended, meaning she had full use her counterweight, she would have been able to right herself in a full knockdown. Even if her mast were below the waterline, even if she lost her mast, maybe more so if she lost her mast, assuming she was watertight, her design would allow her to self recover. With the keel retracted tho, her righting moment would be dramatically less. If she wasn't watertight, a knockdown would be unrecoverable and she would, as she did, quickly end up on the bottom of the ocean.

I have so many questions. We won't know the full story for a bit but seven people losing their lives should have been an avoidable outcome.

This is a one in a million tragedy but we should examine the facts and learn from them. Bayesian boasts the second highest mast in the world at 75 metres on a length of 56m. She has a lifting keel to enable her to get into shallow areas. Fully down it gives a draft of 9.83m and raised a draft of 4m. A sailing yacht has a keel to counter the heeling moment generated by the power of her sail plan. I’m sorry to say that size matters to a superyacht owner and naval architects are seduced into providing solutions. As yacht size increases the resistance of the hull reduces in proportion, so less sail area is required to adequately power longer yachts. But these floating fashion items are driven by appearance and bragging rights - and you lose prestige if someone has a bigger mast than you. Always the status pecking order questions are – how big – how fast – what cost – and is it black? If you designed Bayesian with a reasonable sail area and a ‘normal’ mast she would not look impressiive – which is what superyachts have to be.

The stability of a yacht has to be sufficient to counter the power of the rig but, as mast heights increase, the keels can often become so deep that the places of interest are restricted hence the lifting keel solution. Stability comes from two factors – the hull form and the ballast keel which acts like a pendulum. As the yacht heels the volume of the immersed hull section produce a buoyancy force which resists heeling. Initially the keel gives little force but as the angle of heel increases ‘physics’ makes the keel contribution significant (leverage). The greater the keel length, the greater the effect. The combination of the hull buoyancy on the heeled side and the keel on the ‘windward’ side produces the force necessary to keep the yacht from capsize. If the keel of Bayesian was retracted it would lose a significant six meters of moment arm or leverage from its probable 200 tons of keel bulb. When we design yachts we calculate the stability, or righting lever, as a function of heeled ‘bouyancy’ force and the ballast moment arm combined. (the GZ) This can be plotted on a graph to show the stability at any heel angle and identifies the angle at which stability becomes negative causing the yacht to capsize.

Normally an ocean yacht will experience a negative point at about 120 degrees of heel. With a lifting keel this point is greatly reduced maybe to less than 90 degrees. If Bayesian was at anchor with the keel raised and no sail up the crew would have every confidence that she could remain safe in most normal wind conditions. Every captain at this level has passed an exam on stability and would be aware of his vessels stability graph.

Many years ago I sat at Cremorne and watched a spiralling williwaw race across Sydney harbour and pass through Mosman. This twister was only about 30 metres wide but it destroyed houses and overturned cars in its path. A few feet away nothing was harmed.

The power of a twister is intense and powerful with the wind is coming from every direction. This was what hit Bayesian. The problem of large rigs is windage, even with no sails. But this yacht had three furling sails forward and a big boom with the weight of a furled mainsail inside all above the centre of gravity. Also there were a few communication domes on the spreaders.

We use a wind pressure coefficient to measure the force of the wind on the rig and sails. Even without sails the WPC for Bayesian must have been pretty large when hit by a wind force of varying direction with a local velocity way above the norm. Once she was knocked down beyond her stability limit with the keel up she stood no chance and, laying flat to the water, her deck openings would have allowed a flood of water aboard and she would founder. This would happen in a couple of minutes.

The observation of a lightning strike can be discounted because these vessels are grounded and any damage from a strike would have caused a slow sinking at worst – not a capsize and founder.

The individuals within a professional crew with sailing experience may have sensed the wind and motion of the vessel and quickly reacted to instinctively save themselves in the seconds they had. My guess is that some were already on deck alarmed by the general conditions.The guests would have found themselves totally disoriented in flooding cabins, in darkness with the walls, doors and passageways at ninety degrees to the norm. They had practically no chance because it would be completely beyond their experience. The crew would have been unable to be of any help due to the speed of the unexpected event.

I have been a professional yacht designer and builder for fifty years specialising in lifting keel yachts. My son, a professional navigator, was Third Officer on a ketch superyacht with masts 100m tall; a yacht so big, at 88metres, that it was almost beyond human handling even with the machinery on board. But of course it is the biggest and most expensive’ etc etc. What we have here is a one off accident which is a wake up call to an industry where common sense has departed as yachts get more silly in size and design.

In summary Bayesian was caught in the wrong place at the wrong time. A freak accident which the designers and crew would have little chance to predict.

If the keel had been down she would have probably survived the knock down. But without sails up the crew would have experience of her basic stability for normal conditions which would have felt adequate. Any enquiry must examine the design factors such as the stability vanishing point in the condition she was at the time of the accident; keel up, tank loadings and rig factors for windage (WPC) and centre of gravity etc. And a calculation of the wind force required to heel the boat to 90 degrees in the condition at the time of the accident.

All forms of transport have had these unpredictable one off events leading to changes of regulations and professional practice. Titanic, Boeing, 1955 Le Mans, the 1952 Farnborough crash, the 1979 Fastnet – all have made a difference and these events all came unpredicted and out of the blue often at a time of complacency.

Chris Freer – yacht designer – August 2024

[foolishmortal]

"Eyewitness accounts cited a waterspout — a highly localized spiraling storm that’s essentially a marine tornado"

my good pal Captain Nemo strikes again

[noneun]

Sembra che l'equipaggio dello yacht Bayesian...

... abbia imparato nella maniera più tragica i limiti dell'inferenza bayesiana. Ovvero che, per quante volte sei arrivato in porto senza problemi, è solo molto probabile che lo farai anche oggi: non c'è nessuna garanzia che la prossima volta le tue probabilità di sopravvivenza non colino a picco...

[head-post]

Lynch yacht’s captain James Catfield under investigation

Bayesian yacht captain James Catfield is under investigation on suspicion of shipwreck and manslaughter in the deaths of seven people, Italian media reported on Monday.

Investigators allegedly questioned Catfield for the second time on August 25 to hear explanations as to how the ship, which was considered unsinkable, could have sunk.

The captain was also asked for an address where court documents could be sent. Normally such a step would precede a notice of investigation. Corriere della Sera suggests that Catfield’s deputy and watchman on duty that night may also have received notices.

Earlier this week, Giovanni Costantino, the owner of Bayesian, the company that built the superyacht, said that crew errors led to the tragedy. In particular, he said, the storm was predictable, the yacht should not have been anchored and there should have been no people on board.

Given the severe weather warning, it was “inappropriate” to have a party on the yacht, Costantino noted. However, he described the vessel as “virtually unsinkable,” one of the safest in the world.

The 56-metre British-flagged yacht Bayesian sank due to a storm off the coast of Palermo in Italy on August 19. A total of 22 people were on board, including 10 crew members. 15 passengers were rescued, among them Lynch’s wife Angela Bacares. Seven people died, including British technology tycoon Michael Lynch, Jonathan Bloomer, chairman of the board of directors of Morgan Stanley International, one of the world’s largest investment banks, and Clifford Chance lawyer Chris Morvillo.

Read more HERE

[haute-lifestyle-com]

Italian officials have initiated a manslaughter investigation into the mysterious sinking of the mega-yacht Bayesian, a half mile offshore from the fishing village of Porticello, near Sicily, Italy, in a burst of violent weather, that killed seven passengers

[curiositasmundi]

L’affondamento dello yacht del magnate britannico Mike Lynch comincia a evidenziare alcuni dettagli che alimentano seri sospetti sui contorni della morte sua, del boss della Morgan Stanley, Johnatan Bloomer, del loro avvocato di fiducia e delle rispettive mogli nelle acque di Porticello a Palermo. Non è certo un dettaglio che ben sei agenti speciali britannici si siano precipitati sul posto per capire – o per coprire? – quello che è accaduto.

In primo luogo c’è la morte, appena quattro giorni fa, del numero due dell’azienda di Lynch, Stephen Chamberlain, investito mentre faceva jogging a Stretham, in Gran Bretagna. Chamberlain lavorava come direttore operativo per la società di sicurezza informatica Darktrace, legata al magnate Lynch.

In secondo luogo Lynch era uno squalo della finanza soprattutto nel settore sensibilissimo della cybersicurezza e dunque anche della cyberwar. E in questo settore i punti di contatto con il mondo dell’intelligence e del lavoro sporco sono innumerevoli.

[...]

Darktrace, azienda di sicurezza informatica fondata dal magnate britannico Mike Lynch – una delle sei persone disperse nel naufragio avvenuto ieri a Porticello, nei pressi di Palermo – ha rapporti consolidati con l’intelligence israeliana. Darktrace è ben nota ai servizi segreti internazionali, italiani compresi, ma ha stretti rapporti, in particolare, con quelli israeliani che, secondo una fonte interpellata da “Agenzia Nova”, hanno utilizzato i sistemi dell’azienda britannica per individuare alcuni dei massimi dirigenti di Hamas.

Lynch, noto anche come il “Bill Gates britannico”, ha avuto un ruolo importante nella nascita di Darktrace. La società, infatti, è stata fondata nel 2013 a Cambridge, da matematici ed esperti di difesa informatica di Invoke Capital, altra impresa di proprietà proprio di Lynch.

[...]

’estate scorsa Darktrace aveva presentato sul mercato Heal, il suo nuovo strumento che sfrutta l’intelligenza artificiale per facilitare la fase cosiddetta di “incident response”, ovvero la capacità di rilevare e gestire gli attacchi informatici in modo da ridurre al minimo i danni, i tempi di recupero e i costi totali.

Lo scorso primo marzo l’azienda ha annunciato la nascita di Darktrace Federal, una nuova divisione al servizio del Dipartimento della Difesa degli Stati Uniti, della comunità di intelligence, delle agenzie civili federali e delle infrastrutture critiche nazionali per rafforzare le loro capacità di proteggersi dagli attacchi cyber.

In Darktrace Federal lavorano esperti in materia di sicurezza ed ex membri dell’intelligence statunitense che hanno guidato le operazioni informatiche presso la Cia e fornito assistenza all’Agenzia per la sicurezza nazionale (Nsa) e al Pentagono. Un annuncio che non sorprende, ma che anzi conferma la stretta vicinanza fra l’azienda fondata da Lynch e la comunità internazionale dell’intelligence.

È notizia dello scorso 26 aprile, invece, l’acquisizione di Darktrace da parte del fondo d’investimento statunitense Thoma Bravo per 5,32 miliardi di dollari. La trattativa era iniziata nel 2022 ma aveva subito una battuta d’arresto a causa di una serie di difficoltà nei negoziati fra le dirigenze delle due aziende. Thoma Bravo ha visto l’acquisizione come un’opportunità per rafforzare la propria esposizione nel mercato della sicurezza informatica: d’altronde, il fondo Usa possiede già diverse aziende che operano nel comparto, come Sophos, Proofpoint, Ping Identity e SailPoint.

Per Darktrace, invece, l’acquisizione potrebbe rappresentare un’opportunità di crescita e innovazione: un’operazione “win-win” come si dice in questi casi. Non sempre, tuttavia, sono filati lisci i rapporti fra le società legate a Lynch e gli Stati Uniti. L’imprenditore britannico, infatti, lo scorso giugno era stato scagionato – non senza sorprese – da un tribunale di San Francisco dalle accuse di frode e falso in bilancio presentate da Hewlett Packard. Lynch, infatti, aveva venduto al colosso statunitense del settore high tech, Autonomy, altra società informatica da lui fondata ma era stato accusato di aver gonfiato il valore della società prima della transazione.

Una vicenda che durava da ben 13 anni, quella del contenzioso fra Lynch ed Hewlett Packard che, tuttavia, si era conclusa nel migliore dei modi per l’imprenditore britannico che in questi giorni si stava godendo una vacanza con la famiglia in Italia. La vacanza, però, ha assunto toni decisamente drammatici in seguito del naufragio in Sicilia dello yacht che ospitava, complessivamente, 22 persone.

[...]

[ukdailymail]

CCTV - Moment Bayesian yacht disappears during storm in Sicily

[eltristanexplicitcontent]

56m SailingYacht Bayesian

[lindahall]

John Canton – Scientist of the Day

John Canton, a British mathematician and schoolmaster, was born July 31, 1718, in Stroud, Gloucestershire. 

read more...

[psycheapuleius]

[joshuapaulbarnard]

Predicting Wine Quality

Predicting Wine Quality by comparing Linear Regression with Machine Learning techniques. Comparing Linear Regression with kNN, Decision Tree and Random Forest with Bayesian Inference to Predict Wine Quality in Python. We use python and Jupyter Notebook to download, extract, transform and analyze data about the physicochemical properties which make up wine, and use them to predict…

[head-post]

Last missing body from sunken yacht recovered off Sicily

Italian rescue divers have recovered the body of the last person missing after British technology tycoon Mike Lynch’s family yacht sank off the coast of Sicily and is believed to be his daughter Hannah, a source close to the case told Reuters on Friday.

The British-flagged Bayesian yacht, a 56-metre luxury sailing vessel with 22 passengers and crew, was anchored off the port of Porticello, near Palermo, when it capsized and sank quickly after a pre-dawn storm on Monday.

The source did not say the body belonged to 18-year-old Hannah Lynch, but she was the only person missing. Italian news agency Adnkronos reported that she was found inside the yacht.

The wreck lies at a depth of 50 metres and the passages inside are narrow. On Friday, the fire brigade described the rescue operations as “long and delicate” and said more than 400 people, including 28 specialist divers, were involved.

The bodies of the other five dead passengers, including Lynch, were recovered from inside the yacht on Wednesday and Thursday. The body of the only deceased crew member, chef Recaldo Thomas, was found near the sunken yacht on Monday.

Official identification of the bodies and autopsies are expected to begin after the last body found is taken to a hospital morgue in Palermo.

A judicial enquiry has been launched into the sinking, which has perplexed maritime experts who say the Bayesian, built by Italian luxury yacht builder Perini, should have been able to withstand the storm.

The yacht’s captain, James Cutfield, eight surviving crew members and passengers have been questioned by police but have not commented publicly. Prosecutors leading the investigation are due to hold a press conference on Saturday.

Read more HERE