America’s Cup hydrogen chase boat set to take flight

The prototype chase boat is nothing like we’ve seen before. It will use two 40-kilowatt electric motors powered via a fuel cell fed from four hydrogen tanks housed in the boat’s hulls.

However, propulsion will come from the front of the catamaran via electric motors mounted on the trailing edge of the front foil, with steering coming via a single deep rudder dropping down from the middle of the transom.

Traditional high-speed boats tend to have the propellors down the rear, as the weight of the engines used to power them tend to keep the rear of the boat constantly in contact with the water while the bow is often up out of the water.

Because this new catamaran uses foils that are likely to be tuned to stay a certain depth below the water’s surface, they can mount at the front of the boat.

Also helping the design is the fact that the boats they will chase, the AC40, can really only sail on flat water if they want to use their foils.

The prototype six-seater boat, built using the same production methods and materials as the carbonfibre boats it is designed to keep pace with, is 10 metres long and will weigh around 5200kg once kitted out.

Just 33kg of that displacement will be the hydrogen fuel, stored at minus 250 degrees Celcius and under 350 bar of pressure – the equivalent of being 3.5 kliometres underwater.

The hydrogen will feed into a pair of 80kW hydrogen fuel cells adapted from the Toyota Mirai road car, where a chemical reaction mixes the gas with oxygen from the atmosphere to create water and electricity.

In the road-going version of the fuel cell, the electricity generated by the fuel cell is fed into a battery before it powers the electric motor driving the Mirai’s wheels. The America’s Cup chase boat will use a powertrain system originally developed for a bus to turn the propellors, and the software that will trim the foils to keep the chase boat above the water will be the same as the one that will keep the sailboats aloft..

The chase boat’s brief indicates it should comfortably cruise at up to 35 knots, but be capable of up to 50 knots while drawing on 440kW of peak performance so it can keep pace with the AC40s at full noise.

The anticipated range is anywhere up to 100 nautical miles.

Emirates Team New Zeland mechatronics engineer Michael Rasmussen said the new chase boat was a learning curve for everyone involved. 

“But with that comes really focused engagement from everyone involved to produce something we hope will reach the objectives we set out to achieve in driving a clean change in the global marine industry from down here in New Zealand,” Rasmussen said.

“It will be an exciting yet stressful time once we are ready to get it out onto the water and put it to the test, which seems to be the way with every boat Emirates Team New Zealand creates.”

The prototype boat should launch early next month and will be put through a thorough sea trial to work through all the complex systems involved to get the boat up and flying.

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