The sinking of the 56-metre yacht Bayesian and the tragic deaths of British tech tycoon Mike Lynch and his guests and boat staff have given the public a glimpse into the rarefied world of superyachts, writes Boat International’s Lucy Dunn.

There are currently 12,626 superyachts on the water around the world with 1,166 superyachts in build or on order. If you have been to a Greek island this year, or maybe the Amalfi coast, you may have glimpsed them coming in and out of harbours and wondered who owns a yacht like that. Or who can afford to charter a yacht like that – which have an average price of around £180,000 a week.

While you may think of glossy influencers and A-listers, the superyachting fraternity is where millionaires are sorted from the billionaires from the centi-billionaires; the 0.001 per centers. Rarely will you find a celebrity with the financial clout to afford a yacht owned by Lynch, these are generally under-the-radar industry titans who don’t have household names.

So, what exactly makes a superyacht super? According to Boat International, where I work, it can be applied to any boat, motor or sailing yacht which is over 24 metres in length. Size, in the superyacht world, is everything – and yachts are getting bigger all the time.

A court-appointed armed guard, tasked with ensuring Mike Lynch did not abscond while facing fraud charges, has paid tribute to the tech mogul, saying the security team “became less of a detail and more like a family”.

Rolo Igno also described “the memory of a beautiful soul” in Mr Lynch’s daughter Hannah.

Mr Igno said he had the “privilege” of spending “almost every waking moment” with Mr Lynch while he was in custody in San Francisco, describing the detail as unlike any other he had ever worked and one that was “life changing”.

“As an executive protection agent, the number one rule is simple, don’t ever get close to the principal,” he said.

“They aren’t your friends, they’re a client and the relationship is strictly professional. But with Mike, that didn’t fly with him and for me that rule quickly dissolved.”

The captain of the Bayesian yacht chose not to respond to prosecutors’ questions as he was spoken to for a third time on Tuesday, his lawyer has said.

James Cutfield, a 51-year-old New Zealand national, is under investigation for possible manslaughter and culpable shipwreck charges.

“The captain exercised his right to remain silent for two fundamental reasons,” lawyer Giovanni Rizzuti told reporters. “First, he’s very worn out. Second, we were appointed only on Monday and for a thorough and correct defence case we need to acquire a set of data that at the moment we don’t have.”

Being placed under investigation does not imply guilt or mean that charges will necessarily follow. Chief prosecutor Ambrogio Cartosio has said his team would consider each possible element of responsibility including those of the captain, the crew, individuals in charge of supervision and the yacht’s manufacturer.

The Times reported one of Mr Cutfield’s lawyers as saying that the captain is “understandably very shaken up” after the ordeal last Monday.

Mike Lynch’s wife did not want to leave the scene of the Bayesian wreck without her family, the captain of a boat near the sinking has said.

Karsten Borner, the captain of the Sir Robert Baden Powell, which helped to rescue the 15 survivors of the disaster in Sicily, told People that Angela Bacares “didn’t want to leave because her husband and her daughter were still down”.

British technology tycoon Mr Lynch and one of the daughters he has with Ms Bacares, 18-year-old Hannah, were among the seven people who were killed after his superyacht capsized and went down on 19 August within minutes of being hit by a pre-dawn storm.

Four other crew members, who have not been placed under investigation, have left Palermo.

Two of them headed for Dubai and the other two travelled to Istanbul.

A crew member who has been placed under investigation for manslaughter and shipwreck in connection with the sinking of the Bayesian has now left Palermo, according to a source.

Sailor Matthew Griffith was on watch duty on the night the superyacht sank in Sicily, the source said.

He flew out of Palermo late on Wednesday, with the source saying he was heading for the French city of Nice.

Those under investigation have no obligation to stay in Italy but have to nominate lawyers so that the authorities have a way of remaining in contact with them.

The boat's 51-year-old captain James Cutfield, a New Zealander, and ship engineer Tim Parker Eaton have both been put under investigation for the same crimes.

Members of the yachting community have signalled their support for the captain and crew of the Bayesian as some have been placed under investigation.

One wrote on social media: “Now we need those keyboard warriors and judgemental ‘know it alls’ to actually wait and listen to the unbiased actual professionals ...

“I still stand in support of all Bayesian crew and if things turn sour, I propose all my friends in yachting to stand together and sign a strong petition to support the remaining survived crew to Bayesian.”