For most billionaires, the master suite is the crown jewel of a superyacht. However, on Saudi Crown Prince Mohammed bin Salman Al Saud’s 439-foot Serene one of the most fascinating bedrooms sits three decks below the owner’s suite. Known simply as the “sea cabin,” it wasn’t created to impress with sheer size or lavish ornamentation. Instead, it was engineered around a far more practical goal. It was created to help its occupant sleep comfortably while the yacht is moving.
The unusual cabin has long been associated with reports that Crown Prince Mohammed bin Salman is prone to seasickness. Whether Serene is crossing the Mediterranean or embarking on longer ocean passages, the Balinese-inspired retreat offers a calmer place to rest than the sprawling owner’s suite high above. Rather than chasing panoramic views, the designers focused on the one thing that matters most during rough seas, which is minimizing motion.
A Balinese retreat built around the science of motion
Located on the starboard side amidships on Deck Two, the sea cabin occupies one of the most stable positions aboard Serene’s 134-meter hull. Naval architecture explains why. The bow experiences the greatest rise and fall in head seas, while the stern is more susceptible to pitching, vibration, and movement generated by the propellers. Upper decks also travel through a much larger arc whenever the yacht rolls.
By contrast, a lower-deck cabin positioned close to the vessel’s midpoint remains nearer the yacht’s natural centers of pitch and roll, where movement is least pronounced. Even though Serene is equipped with advanced stabilizers that dramatically reduce rolling, no stabilization system can eliminate every motion during long passages or challenging weather. For anyone susceptible to seasickness, sleeping low and amidships can make a noticeable difference.
The cabin itself is a study in understated luxury. An aft-facing double bed anchors the room beneath a ceiling designed to resemble the underside of a traditional Balinese thatched roof. Earth-toned materials and contemporary Balinese-inspired décor create the atmosphere of a peaceful beach retreat, while a floor-to-ceiling headboard separates the sleeping area from an open-plan bathroom.
One of its signature features is a large shell door that folds down into a private waterside balcony, allowing the occupant to wake almost at sea level when the yacht is peacefully anchored. During passages, however, the balcony remains closed, reinforcing the cabin’s primary role as a practical offshore bedroom rather than a tropical escape.
Designer Pascale Reymond once described it as one of the yacht’s coolest ideas because “it’s so earthy.” The location also adds remarkable convenience. The guest galley sits immediately next door, making it possible to prepare a late-night snack without summoning the crew or navigating several decks. The spa and beach club are only a short walk aft, while a private elevator reportedly links the cabin directly to the principal owner’s suite on Deck Five. The arrangement effectively gives the owner two master bedrooms: an expansive suite with panoramic views for relaxing at anchor and a quieter, lower sea cabin purpose-built for sleeping underway.
The concept itself is not unique, with several large yachts incorporating lower-deck sea cabins near the center of the hull to reduce motion. What makes Serene exceptional is the elaborate Balinese treatment combined with its direct connection to the sea and the owner’s private quarters.
A floating palace designed to have everything
Built by Italy’s Fincantieri and launched in 2011, Serene remains one of the largest yachts ever constructed in the country. Measuring 439 feet (134 meters) with a beam of 60.7 feet (18.5 meters), the Espen Øino-designed exterior wraps around seven expansive decks, while Reymond Langton Design created interiors that balance monumental scale with surprisingly intimate living spaces.
Powered by eight MTU 4000-series engines, the yacht cruises at around 15 knots and reaches a top speed of 20 knots while accommodating up to 24 guests in 12 cabins, supported by a crew of 52, as reported by Charter World.
Few yachts can rival Serene’s extraordinary amenities. There are two helicopter landing pads, one of which transforms into either a swimming pool or a dance floor, a submarine hangar, an underwater Nemo Room inspired by Twenty Thousand Leagues Under the Sea, an observation lounge with domed fireplaces, a conference room, piano lounge, outdoor cinema, beach club, beauty center, hammam, sauna, steam room, multiple spa pools, and a spectacular indoor seawater swimming pool.
Among its most unexpected attractions is the yacht’s famous snow room. Chilled to approximately 12 degrees Fahrenheit, it produces real snow that gently falls from the ceiling, allowing guests to move from freezing temperatures into the sauna, hammam, or warm spa pools. For a yacht designed to spend much of its time in the Middle East, the feature offers an extraordinary way to escape the region’s intense summer heat.
Taken together, Serene’s many luxuries are impressive, but it is the thoughtful details that set her apart. Hidden beneath the owner’s grand suite is a modestly sized Balinese-inspired cabin whose greatest luxury is not extravagance but comfort, proving that on one of the world’s most remarkable superyachts, the smartest design decision may also be the simplest.
