Evidently marvelous
Hydrogen fuel cells generate electricity without combustion, producing only water as a byproduct. Although such cells are already used in the automotive industry and have served as a primary power source in manned spaceflight for over six decades, the marine sector has lacked high-power solutions based on this technology. Moreover, at the project's inception in 2019, there was not even a regulatory framework for the use of hydrogen in maritime fuel cells. Consequently, Feadship's engineers, in collaboration with experts from related industries and Lloyd's Register classification society, developed the equipment, protocols, and safety assessment methodologies that would later form the basis of new regulations.
One of the most formidable challenges was creating a reliable method for storing liquefied hydrogen at minus 253 degrees Celsius aboard a luxury vessel. Hydrogen has a low density: one cubic meter of this gas in liquid form weighs 70 kilograms, whereas the same volume of non-fossil diesel (HVO or e-diesel) weighs approximately 800 kilograms. However, safe onboard hydrogen storage requires a double-walled cryogenic tank housed in a dedicated ventilated compartment, and the volume of this tank must be roughly eight times that of a diesel tank with equivalent energy potential.
Guido Loeff, Head of Research and Development at Feadship, explains that diesel tanks are typically placed within structural voids that cannot be used for other purposes. In the case of cryogenic hydrogen storage, however, the impact on the yacht's architecture is far more significant.
On Breakthrough, the entire power unit—including diesel generators, 16 fuel-cell systems, and the hydrogen tank—is arranged on a single level. As a result, the 92-cubic-meter cryogenic tank (containing about 4 tons of hydrogen), the compact fuel cells, their connection to the DC distribution panel, and the ventilation ducts for water-vapor exhaust added four meters to the yacht's overall length.
Loeff also highlights another important aspect: the fuel cells developed for Project 821 can also operate on methanol—a liquid fuel that is easier to store under ambient conditions. This requires an additional reforming system (steam conversion) that transforms methanol into hydrogen. The resulting hydrogen is then fed into the fuel cell for the electrochemical reaction. According to Loeff, the experience gained from Project 821 makes subsequent steps—using other hydrogen carriers such as methanol—relatively straightforward.
Fuel cells require significant initial investment but offer the highest efficiency as a power source for propulsion systems. The system installed on Breakthrough is already 35% more efficient than conventional generators. In next-generation systems (using methanol), efficiency improvements of 50–75% are anticipated, which will not only reduce emissions but also yield substantial operational savings.
At the same time, according to Feadship representatives, even a yacht of Breakthrough's size cannot carry enough liquefied hydrogen for transoceanic crossings. However, the carbon footprint can be reduced precisely where it is greatest—namely, in generating electricity for hotel loads, equipment charging, and possibly electric tenders. According to the Yacht Environmental Transparency Index (YETI), 70 to 78% of a vessel's annual energy consumption is attributed to hotel services, with the bulk of that going to heating and air conditioning. Shifting this demand to hydrogen fuel cells delivers a rapid and noticeable environmental benefit. An additional advantage is noise reduction: the electrochemical process produces no vibration and has virtually no moving parts, which is especially valuable during nighttime anchoring.
For extended passages or in situations where pure hydrogen is unavailable, power for the 3,200-kilowatt ABB azimuth thrusters is provided by five MTU generators running on HVO—a second-generation biofuel that reduces greenhouse gas emissions by 90 percent. The efficiency of this configuration had previously been validated on other Feadship yachts.
On many modern yachts, large battery banks serve to enable silent operation at anchor or through protected natural areas without starting the generators. Breakthrough is equipped with batteries totaling 543 kilowatt-hours of capacity. For comparison, Feadship's first diesel-electric hybrid—the 83.5-meter Savannah, launched in 2015—had a 1-megawatt power bank. Project 821 does not require as much, since the fuel-cell technology itself allows for up to a week of emissions-free anchoring or speeds of 10 knots in protected marine zones. Here, the batteries are integrated into the overall power grid and are used to smooth peak loads. Thus, maintaining hotel systems on board never requires more than a single generator to be running.
Breakthrough is also equipped with the most effective waste-heat recovery system available today. The "byproduct" thermal energy is used to heat the interiors, hot tubs, sauna, towel warmers, and bathroom floors. Additional savings come from an intelligent climate-control system that automatically reduces cooling or heating in unoccupied spaces.
General Characteristics and Architecture
Project 821 is the largest motor yacht ever built in the Netherlands, slightly edging out Feadship's 118-meter LAUNCHPAD. With nearly the same overall length, Breakthrough is 30 percent more voluminous internally. The yacht features five decks above the waterline and two below. The owner's deck sits nearly 15 meters above the water, yet the silhouette—designed by RWD—maintains a smooth, flowing profile.
The number of opening segments is a record for Feadship yachts. Breakthrough features fourteen retractable balconies, nine large shell doors, and seven sizable opening platforms. When stowed, the balconies are flush with the hull, and deployment is initiated with the push of a button; side rails or glass panels rise automatically, and the fully extended balcony floor aligns seamlessly with the interior flooring.
The interior includes three fireplaces, and the deck features a fire pit, while sliding glass walls can either connect interior spaces with open areas or isolate them. This makes the yacht suitable for year-round cruising in any climate.
As one would expect from a vessel over one hundred meters in length, an entire deck is dedicated to the owner. Situated above the bridge deck, it functions as a penthouse with two bedrooms, two bathrooms and dressing rooms, a gym, and a pantry. The study and conference room are each equipped with fireplaces. The master stateroom is located forward and features panoramic sliding glass walls leading to a private shaded terrace with a hot tub. The 19-meter beam has allowed for spacious interior corridors and comfortable side decks that invite strolls from bow to stern.
However, the owner's domain is not confined to a single deck. A unique vertical corridor descends to the lower deck as a four-story atrium with a staircase surrounded by bookshelves and niches, complemented by a private owner's elevator. Private areas are provided on each level: a coffee corner on the bridge deck, a library on the main deck, and a private dining room with a shell door that opens to form a sea terrace, adjacent to a cabin with en-suite bathroom on the lower deck. This space is finished with teak and woven rattan on the walls and ceiling, lending it an authentic "shipboard" atmosphere. In effect, RWD has created a fully self-contained four-level "townhouse" on board a large yacht. Entrances to this complex are concealed behind wall panels, and without a specific invitation, others on board would not even know of the existence of these spaces. The thoughtful placement of service areas and crew routes facilitates efficient servicing. Separate foyers with elevators and staircases are provided for guests.
The bridge deck accommodates four spacious guest staterooms, each with its own retractable balcony. An interior corridor connects the staterooms to the bridge, the forward helicopter pad (which can also serve as a pickleball or basketball court), the upper-deck salon, and the adjacent outdoor lounge area centered around a fire pit. On the main deck are four VIP staterooms, which can be combined into a suite with a living room or divided into eight separate guest staterooms—each with its own balcony and bathroom. There are also two staff cabins (on the main and lower decks) with access to crew areas and stairways, as well as accommodations for 44 crew members.
The interior design is dominated by a light neutral palette with textured fabrics and leathers. According to project leader Luwerens Hoving, more than one hundred different shades of white are used on board, along with travertine, rattan, and oak wood. Considerable attention has been given to indirect lighting: illuminated baseboards, furniture accents, and multi-level ceilings that create ambient glow. LED strips integrated into built-in furnishings in exterior areas accentuate the yacht's smooth contours and curves.
The beach club comprises four lounge areas, a covered dining area, and folding terraces. Adjacent to it is a full spa complex: hairdresser, manicure salon, massage room, steam room, sauna with plunge pools, and a gym. On the tank deck is a 12-seat Dolby Atmos cinema, which can be converted into a children's playroom.
The most unusual space on the yacht is an underwater lounge located in the keel extension beneath the beach club. Six windows made of double-layer glass, each 7 cm thick and running nearly the full height of the walls, offer views into the underwater world.
The tender fleet on Breakthrough includes one 11.30-meter electric Zin Boat tender, one 12.00-meter limousine tender by Vikal in custom RWD design, and two 7.20-meter Maritime Partner rescue tenders. The yacht's helicopter deck is certified for models such as the AW139 and Airbus 160.
Jan-Bart Verkuyl believes that fuel cells will play a significant role on yachts in the coming years due to their high efficiency, low particulate emissions, and quiet operation. Breakthrough has demonstrated the viability of cryogenic liquid-hydrogen storage technology on a superyacht and has helped establish the necessary standards. This provides a strong foundation for future innovations in fuel cells and methanol-to-hydrogen reforming on superyachts.
Space-Age Technology
The hydrogen molecule is the smallest of all chemical elements on the planet, making this gas extremely difficult to contain within a closed space. Moreover, when mixed with oxygen, it becomes highly explosive. This is precisely why it is critical that hydrogen and air never come into contact—except inside the fuel cell itself. The hydrogen system on board Breakthrough is supplied by the Swedish company PowerCell and externally resembles large white refrigerators; sixteen such modules are arranged in a dedicated compartment. It is here that hydrogen reacts with air to form water and release electrons—a vast number of electrons. Each of these unassuming units can silently generate about 200 kW of power, meaning that the total installation delivers an impressive 3.2 megawatts of electricity.
Bunkering Breakthrough takes approximately six hours and is itself comparable to preparing for a space rocket launch. An exclusion zone is established around the vessel, and personnel working at the "bunkering frontline" are required to wear full protective gear reminiscent of spacesuits. Security must be organized at the dock, and, of course, no guests may be on board the yacht.
To purge explosive air from the pipelines before fuel delivery, the system is first flushed multiple times with inert nitrogen. For this purpose, the yacht carries its own nitrogen-generation unit. Next, a carefully calibrated sequence of operations begins: the system is alternately filled with gas and vented, gradually lowering the temperature—first with cold nitrogen, then with "warm" hydrogen at just −190°C. Only after this can the super-chilled liquid hydrogen be fed into the tank. During the process, gaseous hydrogen is released into the atmosphere through a mast vent.
During bunkering, the vaporizer on the hydrogen-supply tanker draws so much heat from the surrounding air that the air itself liquefies and forms a puddle on the dock. This liquid air mixture, enriched with oxygen, must not come into contact with bitumen in asphalt, as this could lead to combustion. Therefore, in ports where hydrogen bunkering takes place, the docks must be constructed of steel or concrete. At present, the necessary hydrogen refueling infrastructure in Europe exists only in the ports of Amsterdam, Antibes, and on the Norwegian ferry Hydra. In the future, Marseille, Dunkirk, and Greek ports may join this list.
