Absolute zero

Can a superyacht be built without internal combustion engines or diesel generators? That was the core question when, in the summer of 2019, a client of the Fraser brokerage asked for just such a vessel. The yachting world met the idea with skepticism. The future owner wanted not a hybrid yacht with a "green" mode, but a sailing yacht that would live solely on renewable energy. And so Zero was born — a project by three Dutch companies: Vitters shipyard and design studios Dykstra and Vripack. Today it stands as one of the most radical engineering experiments in the industry. Also involved is Foundation⁰, an accelerator for technology and renewable energy development.

Comfortable living aboard large yachts is built around energy redundancy. Powerful generators and substantial fuel tanks ensure the operation of deck equipment, navigation and communication systems, climate control, watermakers — not to mention hot water, lighting, restaurant-grade galleys, cinemas, swimming pools, and the ability to keep to a schedule regardless of wind direction.

Zero breaks the mould. On board, all these systems operate without fossil fuels. The engineers built the vessel "around energy," addressing how to generate it, how to store it, and how to distribute it. Since energy efficiency became the cornerstone of the concept, the first changes affected the yacht's hull. Zero's gross tonnage is 491 GT, roughly half that of some yachts of comparable length. That was the price to pay for the yacht's ability to perform in light winds. In developing the efficient hull, Dykstra specialists drew on software and expertise from Emirates Team New Zealand.

On electric power alone, Zero can cover only about 400 miles, even with a 28-ton battery bank totalling 5 MW — equivalent to 88 Tesla cars. That is why the sails are not just the yacht's primary means of propulsion but also the heart of its energy system. Under sail, Zero begins to generate power itself. Two Hundested propellers, mounted on azimuthing pods forward and aft of the keel, serve as thrusters or, turned forward, operate as hydrogenerators. At a speed of 16 knots, they are expected to deliver up to 250 kW, and at just 8 knots, the yacht should be able to cover all its energy needs. The hydrogenerators consume up to two knots of speed, so the captain will need to carefully choose sailing conditions to maintain the vessel's energy balance. Custom software, created specifically for Zero, analyses weather data and helps plot optimal routes balancing speed and battery charging.

Energy generation on board is also supplemented by hybrid solar panels installed on the superstructure roof. They can produce 20–23 kW of electricity while simultaneously capturing heat.

In parallel, the team tackled the challenge of reducing energy consumption. The first question was: how much energy is truly necessary for comfortable life at sea? The project team installed monitoring sensors on a large yacht and discovered that the main consumers of electricity were air conditioning and water heating. This defined the direction for further work. Thermal energy was also put to use, effectively becoming a form of fuel. Heat recovered from the solar panels, the electric motor, and other equipment is stored in salt-based thermal accumulators and used at night for water heating.

Instead of conventional air conditioners with noisy fans, Zero uses wall and ceiling panels with 12-degree water circulating through them. This system operates far more efficiently than traditional ones, saving up to 300 kWh per day. Natural ventilation through hollow carbon fibre masts from Carbo-Link completes the picture. Heated by the sun, they create a natural draft, drawing stale air out of the interior spaces. The savings from eliminating forced ventilation amount to only 3–4 kW, but the project team did not overlook even such minor improvements. Additional energy is generated by winches when easing sheets, and energy-hungry hydraulic systems have been replaced by more economical electric ones.

"Technical" water — runoff from the sails during rain — is collected and used for washing the deck and rigging, as well as for flushing toilets. This reduces the energy needed for the watermaker. A specially tuned galley extractor hood prevents excessive air loss, while temperature sensors on induction hobs monitor cookware to prevent overheating, optimising energy use during cooking. The freezer is placed inside the larger refrigerator, also contributing to overall efficiency.

Paradoxically, one of the most revolutionary yachts of the decade looks rather conservative. The creators believe that technology should not detract from a yacht's beauty — no futuristic forms or ostentatious eco-signalling. A ketch with classic hull lines and long, "sharp" overhangs, she does not particularly stand out among her peers. Perhaps that is precisely why Zero leaves such a powerful impression. One of the project engineers called her "a wolf in sheep's clothing" — and the description feels remarkably apt.

Beneath the restrained exterior lies one of the most complex information systems ever installed on a sailing yacht. Over a thousand sensors continuously generate data on the yacht's status. Lidars create real-time 3D models of the sail profile, helping the crew maintain optimal trim. The navigation centre plots routes by cross-referencing weather models, battery charge rates, and hydrogenerator efficiency. All data, engineering solutions, and test results are published via Foundation Zero in an open-access format. For an industry that has operated in secrecy for decades, such transparency is a revolution in itself. The creators are equally candid about Zero's limitations. She is entirely dependent on the wind: owners will have to adapt plans to weather windows, and the yacht's early years will effectively be an extension of the testing phase. Moreover, the first refit is already planned for about a year from now — battery technology is evolving too rapidly for the current configuration to be considered final.

The creators of Zero are not trying to convince the world that the project's original goal has been fully achieved. It is viable, open to improvement, and may well become a first step toward the yachting industry of the future.