INSIDE HEESEN’S PROJECT DIANA
INSIDE HEESEN’S PROJECT DIANA
How a proven 55-metre platform evolves to meet modern owner expectations
The 55-metre superyacht segment has long been defined by compromise - vessels large enough to offer genuine ocean-crossing capability, yet compact enough to access a broader range of destinations without the operational complexity of larger gross tonnage. Within this category, Heesen's 55-metre Steel class has established itself as a reliable platform, combining Dutch engineering discipline with proven performance data gathered across multiple deliveries.
Project Diana, currently under construction at Heesen's Oss facility and available for sale, represents the latest iteration of this lineage. Rather than a complete redesign, Project Diana retains the structural and hydrodynamic foundation that has proven successful across sisterships including Solemates (2025), Serena (2024) and Reliance (2023), while introducing targeted refinements that address shifting owner priorities in the 55-metre segment.
The advantage of building on a proven engineering platform lies in the accumulation of operational intelligence. Each delivery generates performance data - fuel consumption patterns, structural behaviour in varied sea states, systems reliability - that informs subsequent builds. Project Diana benefits from this iterative process, incorporating adjustments that elevate the platform without abandoning the attributes that made it appealing in the first place.
A refreshed exterior profile
The exterior design by Omega Architects introduces a sharper, more muscular silhouette, characterised by slanted wheelhouse windows that improve visibility from the helm. The superstructure lines offer a more continuous flow from bow to stern, accentuated by Whisper Grey Awlgrip accents on the mast and superstructure - a departure from the traditional all-white aesthetic.
The redesigned mast serves both functional and aesthetic purposes. “Technically, this structure provides an optimised platform for advanced navigation and communication electronics while managing weight distribution aloft. The design also introduces a strategic customisation point, allowing owners to select bespoke accent colours for the upperworks to distinguish the vessel,” explains Peter van der Zanden, director of design and development and engineering at Heesen.
Rethinking deck functionality
One of the most significant changes on board project Diana is the repositioning of the primary water feature from the sundeck to the main deck aft, where an infinity pool replaces the traditional seating area above the beach club. This layout prioritises active, multifunctional use of space, transforming the lower beach club into a wellness-focused gym and the main deck aft into a more useable guest area.
“Shifting the pool to the main deck aft reflects a clear market preference for integrated aft deck spaces,” explains van der Zanden. “While a conventional sundeck Jacuzzi can create a physical separation from the surroundings, a main deck infinity pool serves as a direct visual bridge between the exterior saloon and the sea. The configuration removes visual barriers, elevates outdoor living and brings guests closer to the water.”
The change also liberates the sundeck, transforming it into a highly versatile space capable of accommodating multiple zones. “The sundeck is typically designated as a very private family area,” explains Silvia Margutti of Luca Dini Design & Architecture, responsible for Project Diana's interior design. “But with all this space, you can create multiple zones. This is something clients often request - a space where you can spend time together and feel connected while still doing different activities. For example, there could be a sit-up bar where someone can enjoy a snack while others relax on sun loungers. This isn't always possible on other decks.”
Shaded areas under the T-top or optional awnings provide flexibility, allowing owners to configure different areas of the sundeck according to preference rather than being locked into rigid layouts.
Sustainable luxury
With an internal volume of 760GT, the interior design philosophy centres on naturalism, tactility and sustainability. Sustainability guides the material choices, with Alpi reconstituted timber and honed marbles delivering a refined finish with a lower environmental impact.
"From a design perspective, we can make better choices in our material selection to minimise environmental impact,” says Margutti. “The challenge in the luxury industry is the misconception that sustainable materials might not be as special, luxurious or unique. But that's simply not true. There's a wonderful range of materials available that are environmentally responsible.”
On Project Diana, almost all the veneers come from certified wood production, and the fabrics feature either threads finished using sustainable methods or sourced from sustainable origins. Even the carpets are made from recycled yarns from other carpets.
The process of selecting sustainable materials requires careful vetting. "We reach out to companies to understand their sustainability processes. We selected leathers that avoided certain harmful chemicals in their treatment process,” Margutti explains.
The interior palette moves between warm whites and blonde-rust hues, where light interacts with texture rather than bold colours. Fluted and sandblasted glass introduces soft, diffused privacy throughout the interior, while natural stone accents - including Rainforest and Camouflage marbles - add depth to bathrooms and cabins.
Accommodation and personalisation
Project Diana accommodates 12 guests across six staterooms, including an 86-square-metre owner's suite on the main deck that stretches the full 9.6-metre beam. Four guest cabins occupy the lower deck, while an enlarged VIP suite on the bridge deck enhances the overall accommodation offering.
"We revised the bridge deck layout to create a larger guest cabin on this level. Previously, it was a lovely cabin with beautiful views, but it could have been bigger. With some reorganisation, we've created a more spacious VIP cabin," Margutti explains.
For prospective owners, early involvement in the design process expands personalisation possibilities. “The earlier the client gets involved, the wider the possibilities for design personalisation, including freestanding items, lamps, cushions, vases and artworks. The client has a broad range of elements they can personalise to express their personality and give character to the yacht. It's always wonderful to work through this process with clients,” says Margutti.
The design intentionally has broad appeal and offers a canvas for future owners to express their individuality while still seeking differentiation from previous builds. “In every design, we try to give it character and find something that differentiates it from previous builds. If a client is buying a 55-metre yacht, they don't want a boat that looks like someone else's,” Margutti adds.
Proven performance
Project Diana's efficiency and low fuel consumption derive from her steel hull refined by Heesen's engineers using real-world performance data from sisterships.
“Perfecting the hull relies on actual data gathered from the extensive operation of preceding sisterships,” explains van der Zanden. “Heesen engineers analysed real-world performance to fine-tune structural weight distribution, optimise underwater appendages and minimise hydrodynamic drag. Such meticulous refinements ensure optimal fuel efficiency and exceptional stability across all sea conditions.”
Paired with compact MTU 4000 M63 IMO Tier III engines, the slippery hull form achieves a top speed of 15.5 knots and a transatlantic range of 4,500 nautical miles. This, combined with a draught of 2.8 metres, qualifies Project Diana as a true go-anywhere yacht - capable of extended ocean passages while retaining access to shallower cruising grounds.
For owners seeking a proven platform with intentional evolution rather than experimental redesign, Project Diana represents the confidence of a tested foundation, refined through operational data and updated to reflect the priorities of modern-day superyacht ownership.
To find out more about Project Diana, get in touch with Heesen directly.
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