Dutch shipyard Moonen delivered "Sofia III" to an experienced yacht owner.

Moonen Shipyards in the Netherlands has launched the 42-metre custom motor yacht Sofia for a repeat client. As well as being the largest superyacht launched to date by the yard, Sofia also features a three-seat submarine, a wide range of other technical innovations, and outstanding noise & vibration attenuation. Inside and out, this highly sophisticated custom project captures the essence of why Moonen is among the finest yacht builders in the world today.

A crossover between go-anywhere expedition vessels and the classic modern yachts that are Moonen’s hallmark, Sofia was custom-designed with safety, functionality and redundancy to the fore. Built to Lloyds and MCA, she implements the latest building techniques with top-of-the-line equipment and systems.

Sofia III by Monnen Yachts
Sofia III by Monnen Yachts
Sofia III by Monnen Yachts

Sofia also brings together some of the finest creative minds and hands in the Dutch superyacht industry. Designed by René van der Velden, Stolk Marimecs was responsible for the complex naval architecture and engineering. Frank Pieterse and Marilyn Bos – de Vaal from Art-Line then went on to develop the remarkable interior, which features a wide range of genuinely innovative features. The experts at Inoferro had their work cut out to incorporate the wealth of stainless steel detailing, as did the woodworkers and many other craftsmen across all disciplines from Moonen Shipyards. The result is a triumph.

Custom made

Sofia was created for a repeat client with bespoke requirements based on his wide range of previous experiences. Having bought his first GRP motor yacht in 1994 and sailed several other vessels around the 80-foot range as well as an X-612 MKII sailing yacht (which he still owns today), Sofia’s owner first teamed up with Moonen almost a decade ago. “In 2004 I embarked on a quest to find a high-quality motor yacht that would allow me to cruise the world in comfort together with the sail yacht,” he explains. “My research led me to Moonen Shipyards, where I purchased the brand-new Moonen 84 Sofia (now Eleonora). I then commissioned a new Moonen 97 to meet my personal requirements, which was duly launched in 2008.

“My experiences with Sofia and Sofia II emphasised the quality of design and build of Moonen. The yachts were safe, solid and reliable even in rough weather. I welcomed many experienced sailors and owners onboard, and all were impressed by the construction quality, low noise levels and immaculate carpentry work.

“When the time came to fashion my new yacht, therefore, the choice to partner again with Moonen was easily made. This third Sofia would be the yard’s largest yacht to date and – unprecedented for her size – carry a private submarine. Although the design started with a two-seat craft, during the construction we switched to a three-seater. This decision influenced the complete design and made the challenge even greater, but Moonen responded with typical flair.

“My yacht was extended and a new crane designed and installed to allow the launch and retrieval of the submarine. Although the alterations were made when the yacht was already at the first stages of construction, the yard handled the complex modifications with minimal delay. Once again, Moonen proved its flexibility, innovative approach and uncompromising commitment to meet and fulfil client wishes.”

We all live in a…

Seeing the submarine neatly housed on Sofia‘s aft deck today, the casual observer will be unaware of how multifaceted such an achievement is. At the time Sofia was initially designed in 2009, the first ‘superyacht submarines’ were being introduced to the market. It is unlikely that the submersible craft companies had a 40-metre yacht in mind to carry a submarine, but the owner of Sofia was instantly captivated by the idea. He is a keen diver and saw that a submarine would be an excellent way to share his joy of the underwater world with friends and family who do not like diving.

The initial contract for Sofia, therefore, specified a two-seat submarine: It was only ten months later that the decision to upgrade to a three-seat version arose. Moonen managing director Emile Bilterijst had trialled a submarine during the 2010 Monaco boat show and realised that to truly enjoy sharing his experiences with someone else, the owner would also need a pilot onboard to take care of operating the submarine.

… Yellow submarine

The yellow submarine on Sofia III
The yellow submarine on Sofia III

The owner instantly saw the wisdom of this approach and placed an order for a C-Quester 3 from U-Boat Worx. At 4.5 tonnes, this high-end submarine was fifty percent heavier than the two-seat version and required extending Sofia by more than four feet in length. In addition to being the ‘smallest’ yacht to carry a submarine that can transport three people to depths of 100 metres, Sofia also became the first yacht to be specifically lengthened to increase the size of her submersible!

But the change had major implications on a number of levels. The greater weight of the new submarine necessitated a much heavier crane to launch. This has been set into Sofia’s stern platform in such a way that it can also be used as a berthing pontoon for the submarine. When the craft is in the water Sofia has a huge beach platform for diving and watersports, while the crane doubles as a mooring pontoon for the tenders too. This unique launching system has been designed to meet all the requirements for Lloyd’s and MCA classification. As a final alteration, an extra tank was placed forward to counter the extra weight of the submarine and crane.

All this was achieved by Moonen as the yard simultaneously went forward with developing and installing the many other technological highlights onboard Sofia, including Quantum zero speed stabilisers, a stern thruster, and a military grade satellite communications system. A major investment was made in installing a thermal camera in the top mast to facilitate shallow water cruising and night-time navigation. Sofia has a full Kaleidoscope video server with multi-room control (including lighting, blinds and climate control) via iPad and a MOB system with personal tracking. This is a high-tech motor yacht in every way.

Added value

Looking at the exterior profile today, it is clear that the four feet added to the original design have merely enhanced Sofia’s charms. There are bold hints of an explorer-type vessel with the wheelhouse relatively far forward. A full beam forward area allows for a capacious owner’s suite and the open sky lounge is another prominent superyacht-style feature. Sofia seems longer than she actually is thanks to the raked profile of the aft decks – just one of a range of elegant details and sensual lines from the pen of Rene van der Velden.

Van der Velden also designed the initial layout for the interior before being joined on the project by Art-Line, who had also worked on the owner’s two previous boats. The result is a plethora of rounded curves, including the phenomenal oval staircase in the centre of the boat with a skylight that bathes the interior with natural light. Art-Line also chose the woods and the fabrics in close conjunction with the owner. A unified colour scheme applies throughout, combining traditional oak and Zebrano veneers with off-white and camel-coloured materials such as coconut paper. All the cabinets have a high degree of complex horizontal joinery, and the entire interior is notably tactile.

“Spatial planning is a very important starting point for every design, and certainly on Sofia where the owner required as great a possible connection between the different decks,” explains Art-Line’s Frank Pieterse. “We set out to enhance the way space is experienced, how the perspectives work, how people move from one area to another. The desire for open spaces meant coming up with various innovative solutions, and our knowledge of the technical possibilities and limitations increased our room for manoeuvre. At Art-Line we are also very aware of how flexible Moonen is as a yard and we were able to lean on each other’s knowledge to create a very special interior.”

Open plan

In practice, this template for an open plan feeling with connections between the decks is instantly recognisable the moment one steps aboard Sofia. Most yachts of this size feature a staircase with corridors on the starboard side on both the main and the bridge deck. On Sofia, however, the bridge deck lobby is situated to port so the visual angle from the main deck entrance is very different from the normal vertical view. Similarly, walking in from the port side on the bridge deck you can see someone entering starboard on the main deck. As part of a stairway that covers three decks, this arrangement exudes roominess.

Another example is found on the lower deck where there is no corridor, just the shape of the staircase with the four guest rooms arranged in such a way that they can be instantly entered. It all looks simple and symmetrical but realising the right spatial division within a single shaped space takes great skill.

And then there is the amazing main deck arrangement. Sofia’s atrium is executed with a custom piece of Concetto, made and supplied by Ceaser Stone in Israel. As well as generating light the staircase also reflects the owner’s desire for a statement of intent which emphasises the height of his yacht. It was a very challenging task to complete because of the way the back-lit marble pillar and stainless steel vertical elements are spread over three stories. In design terms, the edifice serves as a backbone that contrasts superbly with the soft flowing lines found here and elsewhere.

Dedicated research

The atrium is literally and metaphorically connected with the exceptionally open main deck lounge and dining area. The new research allowed the fire petitions to be integrated into the ceiling for the first time on a superyacht. The absence of any hidden sliding doors or walls has a striking effect. The ceiling air outlets and the engine & ventilation room shafts are enclosed within a sculptural element that reflects the natural flow of the air from the air-conditioning units. This element has been painstakingly created from foam covered in coconut paper, with the sides made of Concetto composite stone and the soft shapes being underscored by translucent backlighting. It is very difficult to work such tactile materials into all these different shapes and forms, and the whole piece is a testimony to cool design and considerable craftsmanship.

Despite its prominence, the structural element is still not the main highlight of this area. This honour must go to the perception of width and length which prevails throughout the entire lounge area aft and the separate dining area (seating eight) and bar forward (located on the port side). The sense of spaciousness is reinforced by giant windows. And the shaping of the ceiling comes back in the lounge sofas, the back seats of which move on their own rails. This allows guests to roll the sofa round from looking inwards to watching life glide by outside, still enjoying the comfort of a backrest.

Forward on the main deck to port is a splendid galley, developed in partnership with the chef. Based on her experiences on Sofia II, she visited Moonen during the design stage and also met the owner in the Bahamas to discuss how best to design the kitchen area. The result is all kinds of practical details such as gutters for the water (which speeds up the galley cleaning process), the widespread use of stainless steel, an ingenious system of vents, soft closing cupboard doors and the efficient design of the food service hotline.

There is also a direct connection from the galley down to the crew area, part of a smart logistical arrangement designed to optimise service levels and enhance the crew’s working life. The owner is very committed to crew continuity, which can be seen from the large captain’s cabin, good crew quarters, spacious mess and the light and bright laundry.

Indoor out

‘Outdoor’ aft areas are becoming ever-more sophisticated as owners require the fitting of air conditioning, equipment and other expensive furniture. However, considerable design and construction expertise is required to get these areas right. Sofia is a textbook case of the latter. Her splendid full beam sky lounge can be completely closed off for protection against the elements when underway and yet also be entirely opened up when the owners require.

The giant doors and the way the teak floor continues from the aft deck already create a fine al fresco feel. In addition, the side windows to port and starboard also slide open to leave only the wooden frame. But as the whole area is completely acclimatised, the doors and windows can equally be closed to add to the ‘indoor’ real estate. The semi-transparent sunscreen blinds in the windows are a work of art in themselves, weaving small pieces of a special wood (found by Art-Line in Colombia), copper and plastic to beautiful effect.

The watertight area of the bridge deck begins forward of this area. On the starboard side is a gym which can be completely closed off with hidden sliding walls. There is also a fold-down bed in this space, allowing for conversion into an extra cabin if required. On the port side are a pantry with a small bar and a day head. Furthest forward, the wheelhouse is a controlled space, contemporary but not minimalistic, with a state-of-the-art integrated foil bridge.

Space in the sun

Above all this, we find a phenomenal sundeck with dedicated areas for cooking, seating, a giant Jacuzzi, jet-skis and the owner’s favourite seven-metre Novurania tender. While many owners prefer to have their tenders and large toys stored in the lazarette, Sofia’s owner considers that a waste of prime space. There are two cranes – one on the flybridge and one on the bridge deck aft – positioned in the centre so that the tenders and the jet-skis can be lifted off on either side of the boat. And the tender is actually towed behind Sofia most of the time the owner is onboard, freeing up space on the sundeck.

yacht sofia by moonen yachts 03

Luxurious accommodations

The four guest cabins on the lower deck and the owner’s suite forward on the main deck have a similar style based on a unified colour scheme, leather bedspreads and curtains, and beds made of wicker cane. A natural luxurious summerhouse feel is engendered, with individual colouring provided by details such as the cushions. Overall this provides for an air of coordinated connectivity whereby the individual rooms seem to float into each while each retaining a structure of its own.

To add an extra degree of intricacy, the master suite has even more luxurious leathers, including panels on the back wall imprinted with a delicate pattern and various woven fabrics with leather detailing. The bed has been located more to the port side rather than the traditional central placement, creating space for a proper seating area on the starboard side where the owners can enjoy some private moments together. Featuring a specially made leather sofa in the corner and the coffee table from the owner’s private collection, this set-up allows the seating area to play a key role in emphasising the volume.

The bathroom, walk-in wardrobe and corridor entrance area are all shaped in line with the main lounge, giving a logical feel as the circular effect is continued and still visible in the ceiling. In a similar way, the owner’s bathroom is very much an extension of the suite, with matching colours, materials, detailing and atmosphere. The washbasins have a unique design with a subtle extra glass shelf on top of the marble countertops.

Another cool Art-Line innovation found in the bathrooms are the special trays recessed into the countertops. These smart solutions to the usual storm latches were especially made in Brazil. The same trays are found in the four guest cabins, which also stand out due to their impressive windows and sea level views. There are two aft double cabins and two twins forward which can be converted into doubles if required.

Peace and quiet

All this splendour is enjoyed in peace as Sofia performs as well as she looks. During her sea trials she achieved Class 1 status within the Passenger and Crew Accommodation Comfort notation from the Lloyd’s Register rules and regulations for Special Service Craft. The noise levels allowed for a superior stateroom on a superyacht are 50 db. The tests recorded that Sofia’s staterooms were as low as 40 db in some places and the sound levels never exceeded 46 db at 12 knots service speed even in the cabins closest to the engine room.

A similar accomplishment was noted in the lounge, where the measurements again showed that the sound levels were 4 to 5 dB lower than the figure required to reach Class 1 status. The noise levels were even lower in the wheelhouse, coming in at 45 db in an area where 60 db is still considered comfortable enough for Class 1.

The vibration tests showed an even more remarkable performance. In the staterooms and lounges a maximum vibration level of 0.3 to 0.4 was recorded (compared to an acceptable Class 1 level of 1.8), while the public spaces of the superyacht were measured at 0.4 (compared to an acceptable Class 1 level of 2.5). These low noise and vibration levels are a testimony to the engineering work that went into the design of this custom vessel as well as the phenomenal construction skills of the Moonen craftsmen.

In conclusion

As Sofia left the yard for a summer of cruising in the Mediterranean followed by a winter season in the Caribbean and Alaska, her captain Ian Westman expressed his pleasure at the yacht in his charge. “I have run yachts from four yards at the very highest echelons of the superyacht industry and am convinced that Sofia is on a par with the very best. The amount of interior volume is hugely impressive as are the large aft decks. All this has been achieved within a design that never feels cramped in any way. Like all custom yachts Sofia is a prototype, but this is not noticeable as she performs incredibly well in every respect.”

The last word must go to Sofia’s owner, around whom this project ultimately revolves.

“Moonen has illustrated an unrivalled ability to adapt to new requests and new ideas, in time and on budget,” he concludes. “Sofia is a unique piece of art that places Moonen in the front line of world-class shipyards. My experiences allow me to say without reservation that owners who understand and appreciate building and design quality need look no further than Moonen Shipyards.”

Deck layouts & profile

Main specifications

Length over all:42.76 m
Beam:8.90 m
Draft:2.40 m
Exterior design:René van der Velden
Interior:Art-Line Interiors
Builder:Moonen Shipyards B.V.

About Publisher

Hey, I’m René, the ‘captain’ of this luxury yacht blog. I found my passion of the big ones in 2002 (at the age of 17). I have grown up with sailing since a little child. I have an education in Business Informatics and specialized in digital media solutions like Social Media, User Experience and Social Intranet. I’m working as Luxury Yacht Consultant with YES-yachts.com. My home port is in Oldenburg, Germany next to Lürssen and Abeking & Rasmussen.

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