By far the largest yacht in Port Hercules, Monaco, Lady Moura is a 7,700-tonne colossus stretching 104 metres. Built by the German shipyard Blohm+Voss (the same yard that built the Bismarck), Lady Moura celebrates her 30th birthday in 2020. And having had just one owner in all that time, she’s now up for sale.

Lady Moura’s interior, curated by Italian designer Luigi Sturchio (who created the astonishing 85-metre Nabila for Saudi billionaire Adnan Khashoggi), is luxury by numbers. Gold and cream abound, dark wood surfaces are buffed to within an inch of their lives, and the carpet is so thick that you’re almost wading. You would never guess that 8,400kg of machinery chugs and whirs below.

Among its splendours, the yacht has a 35-cubic-metre indoor swimming pool with a retractable roof. It also boasts a fully functional intensive care unit and a helipad large enough to accommodate any helicopter in the world. Naturally this includes Lady Moura’s own £13 million Sikorsky S76C+. The vessel also comes loaded with a $5 million, 28-metre Mangusta tender, Little Saf.

With a 6,400 gross tonnage volume, Lady Moura is seriously big (even the Royal Yacht Britannia was just 5,769 tonnes). In her dining room I discover two ancient Egypt-inspired mosaics; the gleaming dining table is a staggering eight metres long and has been used only three times in 30 years. In the palatial cabins, super-king-size beds are dwarfed by the sheer volume of acreage around them. There is a walk-in safe in one of the suites.

Her pre-eminence in the yachting world back in the early Nineties soon becomes apparent. Today Lady Moura is widely considered to be the first superyacht, partly because of her magnitude but also because of the countless ‘firsts’ found on board.

She is one of the first yachts to have beach clubs that open up on the ship’s sides (or indeed to have beach clubs at all), as well as one of the first to include boat garages, extendable bridge wings and numerous gangways.

Lady Moura has been maintained with regular small upgrades rather than any major refits, with her longest yard period to date being a seven-month stay at Blohm+Voss in Hamburg in 2017. She is in impeccable condition considering, and her iconic reputation makes Lady Moura’s ‘for sale’ status a big deal in floaty circles. She is rumoured to have cost more than $200 million to build, and one Monaco-based brokerage has hinted that yachts of Lady Moura’s stature ‘usually retain their value’.

Another source, however, has floated $150 million, considering her 30 years of wear and tear and particular style: Saudi-owned yachts are generally considered traditional in their design and come with limited outdoor space. However, the yacht remains the biggest sales task that broker Camper & Nicholsons has ever had. Over a few glasses of Louis Roederer champagne served aboard Lady Moura, the ship’s chef serves up a lunch including a starter covered in edible flowers, perfectly seared scallops, and tiramisu.

Captain Matthias Bosse reflects on his 18 years at the helm of Lady Moura: ‘You can build the most incredible vessels, but it is time that fills a boat with a certain spirit. When you come on board you get goosebumps – you can’t build that in.’

Lady Moura, it is stressed, is a family yacht. She was the primary residence of the owner, Saudi billionaire Nasser al Rashid, and his six sons and three daughters were raised on board. It is said that the crew and staff (many of whom have been with the yacht for decades) still refer to them as ‘the children’. Lady Moura has never been chartered, and everything – carpets, curtains, furnishings – is original.

But it’s not just the yacht’s floating credentials that make it attractive to potential buyers, there’s also its provenance. Her owner has made his billions in engineering – Forbes has estimated his wealth at about $8 billion, but it could be closer to $20 billion.

Al Rashid was educated at the University of Texas (he has since lavished funds on the university and had a department named in his honour) before setting up a firm in Riyadh, which was later chosen by Saudi kings Khalid and Fahd to be the engineering consultant to the royal family – and became one of the largest engineering firms in the kingdom. He remains an adviser to King Abdullah.

Now in his eighties, al Rashid dedicates much of his time to philanthropy, sitting on the board of charitable initiatives such as the Handicapped Children’s Association, the Prince Salman Centre for Disability Research and the National SeaKeepers Society. He is also a co-founder of the Prince Albert II of Monaco Foundation.

Back when al Rashid was studying in Texas, George Bush Sr was making his first steps into Congress: the pair became acquainted and were close enough for Bush to later be a guest aboard Lady Moura. In her autobiography, Barbara Bush recalls a trip to sea on the yacht with ‘our friend’ Nasser al Rashid in May 1999.

One can only imagine the conversations that took place aboard the yacht between the former president and billionaire confidant of the Saudi sovereign in the midst of the Iraq disarmament crisis.

Interestingly, despite his Bush connections, al Rashid also donated millions to the Clinton Foundation, and the family has poured more than $1 million into Democratic coffers over the years. That Bill Clinton ousted Bush from the White House in the 1992 election was unlikely to be a topic of conversation.

Captain Bosse is right: the colossal vessel creaks with history and likely as not secrets as she moves almost imperceptibly on the Mediterranean swell. And yet the captain’s misty-eyed version of events doesn’t tell the whole story.

So it is symbolic, perhaps, that the namesake is estranged from her family: after the pair divorced in 1996 she wrote a memoir, La Vérité, alleging al Rashid’s marital abuse. Describing the fairy-tale match of a budding socialite and the tycoon, Ayoub revealed the harsh reality of being a Saudi billionaire’s wife: she was forbidden to speak to men, to see female friends her husband didn’t approve of, and to play sport or speak loudly in public. During holidays aboard Lady Moura, she recalls disguising herself as one of the crew in order to go ashore.

When asked why the owner was selling such a treasured family heirloom, Camper & Nicholsons CEO Paolo Casani alluded to complexity behind the sale. ‘He has many reasons for selling,’ said Casani of the owner. ‘You don’t decide to sell a yacht that you have had for 30 years overnight.’ You certainly don’t. Perhaps an answer is hiding in plain view. On al Rashid’s personal website, alongside details of his career and achievements, it notes: ‘His favourite hobby is walking.’

More likely he has reached an age when the attractions of life afloat are less apparent. Or perhaps he simply wants to be closer to his grown-up family, who have provided him with five grandchildren.

It doesn’t really matter. What’s more interesting is what happens next, who the next owner is. For the second chapter in Lady Moura’s voyage to match her first, they have pretty big deckshoes to fill.