The 2023 Monaco Yacht Show debuts Feadship’s twelfth cutting-edge Concept Design, an 83-metre superyacht with significantly reduced energy needs. Dunes combines a lot of sustainable solutions, ranging from methanol and a new propulsion system to low impact steel and wind energy to slash a superyacht’s environmental impact.
Flowing lines from Studio De Voogt reflect the concept’s namesake, Dunes, while the mast and stern add an air of mystery to the organic shapes of the superstructure. Dunes takes a big leap toward Feadship’s goal of net-zero superyachts. Like a complex 3D puzzle, it combines features that reduce energy demand with technology that increases efficiency and eliminates emissions.
Numerous factors, from shading windows to reduce cooling requirements to extra-capacity next-generation storage batteries, to abolishing teak decks, a new type of fuel cells, and even a radical propulsor, link in a beneficial design spiral. Alone, each element reduces environmental impact, but together, Dunes will slash a superyacht’s environmental impact.
Assessed using the comprehensive Yacht Environmental Transparency Index (YETI) tooling, Dunes eliminates up to 95 per cent of the potential negative environmental factors associated with operating a superyacht compared to a yacht meeting today’s minimum environmental regulations.
Asking the right questions
‘Before we could begin drawing lines, we had to define the scope,’ says designer Thijs Orth, who took the lead on this concept. ‘From customer input, we thought the “envelope” should contain six guest staterooms, plus a spa area, a beach club, an owner’s private deck and a pool. It would be a substantial hull.’
Then came a barrage of “what-ifs”. What if the engine room does not sit in the middle of the yacht? What if guest staterooms could have direct access to the beach club? What if we moved the bridge as on Concept Pure (2021)? What if the fuel cells don’t require hydrogen storage tanks? What if there is an entire multipurpose deck? What if we update the passive ventilation system of Concept Breathe (2010)?
What if the superstructure is asymmetrical? What if the decks themselves could generate electricity? These and other questions led to new solutions for old problems.
Entirely new layout
The knock-on effects of just one change – moving the engine room from the most comfortable spot on a boat to areas forward — opened up the possibility of an entirely new layout where lower deck guest suites link to a beach club, water sports platform, and the pool above.
This also eliminates large engine room air and exhaust trunks from compromising saloons or dictating stairway placement. Electric yachts do not need huge gearboxes, long shafts and propellors. Electricity-generating fuel cells, battery banks and the power management station can be decentralised and located virtually anywhere convenient to the crew. A virtual helm station or command centre on the lower deck next to the crew quarters rather than several decks away where it compromises owner/guest space is feasible.
For aesthetic inspiration, Studio De Voogt focused on undulating waves, not of water, but of sand. Noticing how dunes are never fixed, their ripples and valleys appearing to shift with light and shadow, the designers explored ideas about line, flow, and adaptability.
Dunes undulating curves emerged as a backdrop for the onboard lifestyle today’s owners desire with adaptable, multi-purpose spaces, views, and a mix of open-plan areas and cosy, intimate spaces.
While decks often get squeezed by indoor accommodation, shady walk-around decks are a main feature of this design. In addition to the feeling of being protected from the elements, they offer alternate circulation routes around the yacht as well as outdoor seating and entertaining areas.
An instantly recognisable feature of Dunes is that its asymmetrical superstructure has almost no straight lines. Staircases are circular or gently curved. So, too, are windows and doors of full-height glass. This much glass could create tremendous heat loads in sunny climates were it not for attention to overhangs. A calculation showed these decrease heat building behind the glass by sixty per cent.
A broader look at sustainability
Sustainability is more than controlling exhaust emissions. With an international treaty prohibiting old-growth Burmese teak imports by all the world’s major yacht-building nations, and demand far outpacing the supply of suitable plantation-grown teak, the responsible position is to move on. Dunes is teak-free. Two new luxury decking systems being tested by Feadship combine for this concept.
Outside, the topsides shimmer with teak-free decks made of millions of tiny glass or stone chips sealed in a transparent aliphatic polyurethane resin. The resin surface can be sculpted in myriad shapes to show direction or amplify the impact of built-in features.
Notably, the uppermost Pavilion Deck structure is built of wood. While this is how early Feadships, and in fact, most steel-hulled vessels, were built in the days before aluminium, this choice is based not on a quirky juxtaposition with the past, but on science. Treated timber is a CO2-negative building material with a high natural insulating capacity. This benefit comes without increasing its overall weight.
Also read: Latest Feadship yacht leaves dry dock
Cool Core Concept
Further reducing the amount of energy needed to cool the yacht, the mast is part of Studio De Voogt’s Cool Core Concept. Like a desert house, Dunes is divided into temperature zones. Sleeping quarters are cool (19-20 degrees), social areas are about 22-23 degrees, and the Pavilion estimate is 24-25 degrees.
The Pavilion is cooled using air drawn up the central staircase from other parts of the ship without the use of fans and ducts. It is simple physics that makes it work. The mast shape is a triangle of convex and concave foils. It sits on a large bearing ring that allows it to align with the direction of the wind.
As the breeze crosses the mast, its shape generates a low-pressure zone on the leeside, naturally pulling the slightly over-pressurised cooled air from lower decks to this level. Together with the large overhangs, optimised recirculation, and increased insulation throughout, Feadship calculates that HVAC energy use is reduced by 35 per cent on an annual basis.
Wind and solar energy
The wind, as they say, is free, and so is the electricity generated by a wind turbine or the sun. Feadship engineers devised a slim, two-blade vane that nearly disappears in the mast structure. Used only at anchor, this turbine can yield about 25 MWh per year.
Dunes’ foredeck could be coated with a thin film solar panel. Called solar paint, this technology is in its infancy and its efficiency today is low. Currently, the effect is the proverbial drop in the ocean. But why not collect it?
Dunes introduces a high-efficiency electric propulsion system from ABB called ABB Dynafin unveiled last May. In development and testing for ten years, the ABB Dynafin utilises revolving, vertical blades to mimic the thrust of a whale’s tail – one of the most efficient forms of thrust ever seen.
The first prototype is estimated to be available in 2025, with hydrodynamic efficiency targeted to be up to 85 per cent, up from 65 per cent for current pod drives, or 55 to sixty per cent for typical propellors on shafts.
An independent study of ABB Dynafin of a passenger vessel design equipped with different propulsion solutions has verified savings in propulsion energy consumption of up to 22 per cent compared to conventional shaft line configuration.
The Dynafin propulsion will be driven by electricity generated from solid oxide fuel cells that use green methanol as a reaction agent. Methanol can be converted to hydrogen in one step and does not require cryogenic storage. Green methanol (produced from non-fossil-fuel sources) is seen by Feadship as the best fuel option, due to the relatively high energy density and ease of storage.
Senior Specialist Bram Jongepier: ‘Contrary to the common assumption that using methanol means more than two times the fuel storage volume, on Dunes, we have so many power savings that we actually need less storage volume compared to a regular diesel fuel yacht.’
Low impact steel and aluminium
Feadship is making a quantum sustainability leap at the beginning of the construction process by shifting to “low impact” steel and aluminium for hulls and superstructures, which make up more than half of the build CO2 impact. Using a high scrap content and sustainable energy in the manufacturing process, these certified metals can be produced with fifty to seventy per cent less CO2 emissions.
Feadship has already integrated low-impact aluminium on one vessel in build and made it standard material for all future new builds.