The launch of the ship is still three and a half years away.

The floating residences cost between US$4.4 million and US$36 million – and many of the largest flats have been bought already, David Robb, founder and chairman of the Utopia project, told Business Insider.

“We describe it as the largest private yacht in the world,” Robb said.

“Cruise ships are built to last 25 to 30 years.

“We’re building Utopia to a 100-year specification. There’s nothing like that in the world.”

Utopia’s luxury residences are designed to be comparable to luxury flats in major cities such as New York or London.

Robb said the team had gone to great lengths to design open floor-plan kitchens so that “someone with a beautiful apartment in New York would say, ‘This kitchen looks just like what I have in my luxury apartment’.

“[But] you can look out at the ocean. You can be preparing drinks while you’re watching the islands go by outside.”

The ship’s 190 flats come in a variety of sizes and floor plans, ranging from about 1,500 square feet (140 square metres) up to 6,200 square feet.

Every bedroom had an ocean view, Robb said.

The company had told its naval architects that it wanted the ship to look “like a gorgeous luxury apartment in Central Park South”.

He said: “It has to be elegant and timeless. We can’t be chasing fads because this is going to last a long time.

“We also told the architects that if it looks like a cruise ship anywhere on the inside, they are all fired.”

Entertainment on board the Utopia will include a theatre, a nightclub, jazz lounges, a casino, an art gallery and a golf putting green.

Residents will have plenty of ways to stay fit aboard the ship, including a walking track, a complete gym, multiple swimming pools and a multi-deck water slide, paddle tennis and fitness classes.

There will also be a luxury boutique hotel on board with 160 rooms so residents can invite guests, including in-laws, children and grandchildren on board without having to invest in a larger apartment.

Robb said most of the buyers so far were businesspeople and philanthropically minded individuals, including artists and fine art collectors.

“I think what [Utopia] does is attract people who want to find something unique that they wouldn’t otherwise see in a normal travel experience,” he said.

“You can’t buy experiences. They’re going to places and doing it in a way they wouldn’t otherwise.”

Utopia is being created by some of the same team that developed The World, a similar condo cruise ship launched in 2002, which accepted only buyers with at least US$10 million in assets, Bloomberg reported.

However, Robb said Utopia had improved upon The World in terms of design, comfort and economics for the residents.

With Utopia, the company had provided “the ultimate answer” for people who wanted to see the world but did not want to abandon the luxuries and comforts of home, he said.

“That’s kind of a revolutionary concept, travelling to remote parts of the world and having all of the infrastructure that you have at home.” he said.

Beyond its residential focus, Utopia sets itself apart from traditional cruise ships by travelling the globe in one direction instead of making round trips in and out of ports.

The ship will also stay in one port for up to a week as opposed to most cruise ships that stop for fewer than 24 hours.

“The most luxurious way to travel, I think, is to go into the heart of the country, to get out of the big cities and see what the countryside’s like and how people really live,” Robb said.

“That’s what we’ll be able to do with this kind of itinerary, and that’s unique.”

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This article originally appeared on Business Insider.