The TU Delft Hydromotion Team will race its new boat – revealed on Wednesday, 18 December – in the Monaco Sea Lab 2025. The goal: to win the race and prove the potential of a liquid hydrogen system as a maritime technology. It will also be the first time that a liquid hydrogen-powered boat competes in this race.
Last night, the Hydromotion Team revealed the 2025 design. The boat measures 7.25 x 2.20 metres. It has three adjustable hydrofoils and is liquid hydrogen-powered. It will have a 40-kW fuel cell installed and carries 8 kg of liquid hydrogen. The boat is to reach a cruising speed of 40 km per hour.
The boat has been designed to compete in the three challenges of the Monaco Sea Lab. The first is a high-speed challenge in 1-km race. This requires a high top speed and fast acceleration.
The second is the manoeuvrability challenge in Monaco’s port and involves navigating a low-speed course with tight turns, mooring and casting off, making precision and control essential. The last one is the endurance challenge, requiring long-distance sailing. For this challenge, the boat needs to sail as much distance as possible within four hours.
Also read: TU Delft Hydro Motion Team crosses North Sea with hydrogen boat
Designing the boat
As the boat sails on hydrofoils, lifting the hull completely from the water, the boat had to be as light as possible. That is why the hull is made from carbon fibre. Not all parts need the strength of the carbon fibre, therefore, some parts, such as tank caps and hatches, have been made from Flax, a more sustainable option. Flax is a biocomposite, produced out of renewable materials (the flax plant).
Composite materials have a strong ten-cell strength (pulling direction). To also strengthen its bending strength, foam is being applied in between the two carbon layers.
For the hull, the V-shape has been chosen for its good allround performance. The boat’s sharp bow cuts through waves efficiently. A chine has been added to assist in lifting the boat out of the water. The design is quite similar to the boat of 2023, which won the Monaco open sea class. Due to its good performance, it was decided to reuse the mould of this boat. As a bonus, this also saves material.
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Liquid hydrogen
Hydrogen has the advantage that it is an incredibly light gas for the amount of energy that it contains, according to the Team. It contains three times as much energy as diesel for the same amount of mass. However, its low density necessitates storing it under high pressure. The student team did this in a compressed hydrogen tank, also made out of carbon fibre. This is a tank of 350 litres, storing gaseous hydrogen under the high pressure of 350 bar. This means, the boat only carries 8 kg of hydrogen.
However, this year, the team is transitioning to liquid hydrogen, because it is three times as energy dense as compressed hydrogen gas and it doesn’t require high pressure. This significantly reduces the required storage volume allowing for more efficient use of space. A critical advantage for long-range maritime applications. Yet, storing hydrogen in its liquid form at -253°C presents significant challenges.
The TU Delft boat cannot actively cool the hydrogen, meaning it will be boiling constantly in the tank. This means heat transfer from the outside to the hydrogen has to be limited to prevent a pressure build up in the tank due to evaporation. That is why a custom cryogenic tank is being developed with multi-layer insulation and double walls with a vacuum in between. This limits heat transfer to just 7 W.
The liquid hydrogen also has to enter the fuel cell in the same form as the hydrogen gas from the gas tank. This means it has to be heated up from -253°C to 20°C. This is energy-consuming. Therefore, it has been decided to combine the cooling loop from the fuel cell with the heating loop of the liquid hydrogen. Using the fuel cell’s waste heat to heat up the liquid hydrogen.
Batteries and electric motor
The boat is also fitted with batteries, which the team calls its buffer. It is made up of over 200 lithium ion phosphate cells. It charges or discharges as needed to adapt to changing power demands, while the fuel cell provides a steady stream of electricity.
An electric motor is connected to a drive shaft, which runs throught the rear strut. This mechanical energy is then transferred to a propeller by two baffle gears. The propeller is placed at the front of the rear strut to improve efficiency due to the flow over the rear foil. It is also placed at the very bottom of the strut to ensure it stays submerged, even when foiling.
Also read: VIDEO: TU Delft Hydro Motion Team reveals 2024 design
Struts and hydrofoils
The boat has three struts, two in front, one under the stern (with the propeller. The strut length is 1.84 metres. A strut is basically a long aluminium rod. Aluminium was chosen to ensure the strut’s strength and keep it lightweight. To manoeuvre, the boat has a 180-degree rotatable rear strut, combined with the ability to reverse the propeller’s rotation.
The hull has a draught of just 30 centimetres. Its most important task is supporting the hydrofoils. At a speed of around 25 km per hour, the hydrofoils provide enough lift to raise the boat out of the water. Precise control of these hydrofoils is essential to ensure the boat’s stability. When sailing in waves, the pitch of all three foils can be adjusted independently allowing for smooth sailing.
Controlling the hydrofoils
Active height control adjusts the positions of the hydrofoils as needed. An accelerometer measures the linear acceleration in all three directions, while an ultrasonic sensor measures the real-time distance from the boat to the water. This data is fed into an algorithm written by the Hydro Motion Team. This then calculates the ideal pitch positions to keep the boat foiling and stable.
A data acquisition system monitors the boat’s real-time performance via an Internet connection. It also allows the team to share their live location and the status of the boat when sailing. The data from previous years is used to improve the boat further.
Picture: Still from the reveal video, by TU Delft Hydromotion Team.
Also read: VIDEO: TU Delft Hydro Motion Team reveals new boat
