A yacht should allow you to feel comfortable and relaxed,” says the owner of Numptia, explaining the philosophy that drove him to create the wonderful 70-metre launched by the Rossinavi yard last year. We’re sitting outside around a table on the staggering spa deck, one of the yacht’s many comfortable and relaxing spots. “You can feel this way at home because over the years you’ve managed to create an environment that suits you. A yacht should feel like this, should feel like home.”

‘Home’ is a usefully reassuring reference point for a yacht that confounds expectation in many ways and which, like the most engaging of modern homes, is full of quirks and characterful flourishes.

Take a closer look at superyacht Numptia in our gallery.

The creation of Numptia started nearly five years ago, with the owner eager to expand on the lessons learned aboard his only previous yacht, a 60-metre CRN launched in 2000 (the first Numptia). And in the grandest of yachting traditions, all he needed to get started were those most vital of tools – “a piece of paper and a pencil”, he says.

Quickly on board was the exterior designer Tommaso Spadolini, and the pencil and paper were soon busy. “My preliminary profile was very similar to the yacht we see today. Numptia is made up of many continuous curved lines – longitudinal, vertical and transverse. It is these that make her look like a yacht rather than a replica of a ship,” Spadolini says. Indeed, the long sweep of the blue hull curving downward aft and the gentle curves higher in the superstructure give the yacht a pleasing appearance on the water, while the series of aft decks, arranged in an elegantly proportioned cascade, add a touch of architectural drama.

But at the preliminary stage, an LOA still needed fixing and the first thought was that 60 metres was enough. “But I wanted a main salon with a full wraparound view out. I always remarked on why designers occupy those prime spaces with storage, staircases and air trunks. I asked if we could design it with those things moved forward. But in order to do that the engineroom had to move and in a 60-metre yacht that wouldn’t have been possible, so that’s why we ended up with 70 metres. The living room decided the length of the yacht and the layout,” the owner explains.

And what a living room! The after area – so often a largely ignored slab of sofas – is opened up thrillingly with the almost deck-to-ceiling windows allowing a wonderful connection with the outside world. Moving forward, the space narrows to accommodate the service items, and the confines have been filled with a cosy bar. The contrast with the light-filled sofa area is dramatic, creating a more intimate space that is perfect for late evenings.

“Every time a decision was made, we asked the question: ‘Does it welcome me? Do I want to stay here?’ I do the same thing in a restaurant: if I don’t like the table I’m given, I ask to move. Aboard Numptia, I want everyone to have a positive answer to the question ‘Do I feel comfortable?’ It’s not an easy thing to do in a space-conscious environment like this,” says the owner. You don’t have to spend long on board to understand how successful he has been in creating a yacht that for all the artistry and craftsmanship on display, remains welcoming and informal.

The interior by Achille Salvagni breathes life into the home-from-home theme. His philosophy, he says, is that: “Good design does not begin with decorating but defining the architectural vocabulary of space. I never separate the different living areas, preferring fluid spaces for different purposes.” Aboard Numptia you see the philosophy in action everywhere: the owner’s suite is a tremendously calming space to enter, but also a very practical one, with a TV area to port and a reading area to starboard. A level higher, the bridge deck lounge also makes use of the ‘constricted middle’ that is exploited with such success on the main deck. A 103in screen runs along the starboard side, and opposite is one of the most welcoming extended sofas (a huge bed, in truth) you’re ever likely to see. It’s already proving popular with guests – “One of our morning jobs is checking between the cushions for popcorn,” one of the crew told me. And, like everywhere else on Numptia, there are plenty of choices – welcoming armchairs around a coffee table, or further after a pair of games tables for more sociable gatherings. And, of course, there’s outside, blessed with bigger tables for informal dining and sofas facing aft.

There are options aplenty and the space to make it comfortable – most of the charter party could happily stay on this deck, served by the port-side pantry. But, of course, the whole yacht is about the options it gives you, and the spa deck is one of its winning features. “On yachts, gyms and spas are often treated as afterthoughts,” says the owner. “I wanted to devote an entire level to these facilities. It’s the lifestyle today. People on vacation are thinking about their health and physical activity. It’s a big part of their relaxation.”

Once again, options… The gym has wonderful views out from on board the machines and there’s even a seating area if it all gets too much. Forward, there’s the steam room, hammam, massage room and hairdressing salon, while outside there is a range of options on deck – places to eat, sit, read or sunbathe. “It was enough for an entire deck,” says the owner. “The idea is that you come up here in your bathrobe in the morning and you can spend the entire day between the spa deck and the sundeck. The next time you go to your cabin is when you get ready for dinner in the evening.”

Again, as with the bridge deck and the main deck, these are spaces that you and your party can occupy for lengthy periods without running out of things to do. The sundeck is another option-friendly area, as are the guest cabins: there are three doubles and a twin on the lower deck, and an extra double on the bridge deck, with a superb view out from the bed. “They are a standard size, but I made sure that if you wanted to write a letter, read a book or watch a movie, you could do those things,” the owner says.

“Each deck has its own personality,” says Salvagni. “But the aim is that they all fit harmoniously together to form a stylish whole, whose result is a sense of continuity.” Much of this effect is achieved by the use of bleached teak throughout, which helps to establish the subtly calming vibe.

“This is where the challenge comes in,” adds the owner. “Every one of these rooms has to create a level of intimacy, to make you want to sit there, to relax and talk. I think we managed to do that.”

Much of the owner’s praise is reserved for the Rossinavi yard, a relatively unknown player in the superyacht sector, but one who immediately bought into the project. “I had a yard that allowed us to design as we were going along!” the owner quips. “They knew that they were building a 70-metre yacht, but exactly what it looked like, they didn’t know. I couldn’t be a client that goes to a yard with all those decisions already taken.” Rossinavi also had to accommodate an owner who was on site every month for up to a week for the duration of the build, but the process worked well. The designers, too, had plenty of interaction with the owner – “daily telephone calls and renderings”, says Tommaso Spadolini. But the working relationships were clearly fruitful, the major point of difference being occasional misunderstandings when Spadolini and Salvagni used metric and the owner imperial. “At the end of the build Mr Salvagni gifted me a dual measuring tape. It was a little late!” the owner says.

For the winter, Numptia is in the Caribbean and clearly has a successful charter career ahead – few yachts offer you so much choice. The owner confesses to a personal ambition: “I want to take her up the Hudson and under the Brooklyn Bridge. Then the hope is she’ll travel the world. I share the yacht with my two brothers. We’re a big family. She’ll be very busy!” Be it a big charter party or an extended family cruise, Numptia will deal with it all without blinking.

“A lot of new yachts today just evolve from a previous version or are series offerings. An arrangement like that is great for the shipyards, but not great for the owner who is trying to create something unique and wants his yacht to be a personal yacht. To each his own, of course, but I didn’t want that, and I’m very happy with the result. It was worth four years of planning and working with people I respect.” And judging by his broad smile, the owner enjoyed every minute that went into creating this unique and personal yacht.