48 Breeze Magazine
Early testing of the ETNZ hydrogen chase boat on Auckland’s Waitemata Harbour. in this project. At this stage, compressed hydrogen is the only viable option, which requires heavy pressure vessels for storage. “For every kg of compressed hydrogen, you need many, many more kgs in the weight of the storage tanks,” says Bernasconi. Once the complexities of the power source had been understood, the team moved into more familiar territory with the design of the platform and foiling system. The main foil is described as an inverted Greek letter pi (�), with vertical struts projecting down from each hull. A horizontal foil connects the two struts and projects winglets out beyond the struts. Four control flaps are arrayed along the horizontal surfaces. The electric motors are positioned inside the hulls directly above the vertical struts. They drive vertical shafts within the struts to a bevel gear at the bottom connecting a short horizontal drive shaft to the propellers, like the bottom end of an outboard motor. The main foil is balanced by an inverted T-shape foil on the single, centreline rudder, which is very similar to the setup of an AC75 rudder. Just like an AC75, the boat will foil at about 18-20 knots. The 50-knot top speed requires a combination of hydrogen and battery power, but those bursts are fairly rare and short. Most of the time cruising at 30 knots, the motors run on hydrogen power alone with reserve power being used to top up the batteries.
In terms of control, the helm is conventional with a steering wheel and throttle control. The foiling system is automatic, controlling ride height and even countering heel in turning manoeuvres. “It shouldn’t even spill the coffee in tight turns,” smiles Bernasconi. The Protocol stipulates that, once the concept has been proven in trials, all the teams must have at least two hydrogen-powered chase boats meeting the same set of specifications. “The teams are welcome to build their own hydrogen chase boats if they want to,” says Shoebridge, “but indications are that most, if not all of them, will order boats from us. “The challenger teams can be sure that we will produce these boats as cost-effectively as we can. This is not a revenue exercise for us. It is about trying to pave the way for something new and better in the sport.” Coming on top of a land speed record machine, a world-first production run of potentially 10 or more hydrogen boats, an AC40 design in addition to one new AC75 yacht, all this activity suggests ETNZ’s design, engineering and boatbuilding teams will have no difficulty justifying their salary, or overtime, bills over the next couple of years. Nor will the team have any problem justifying its credentials as a leading-edge technology company.
