Courtesy CandelaHydrofoil technology has been around since 1869, when Emmanuel Farcot received a British patent for using wedges to lift a boat above the water’s surface. But despite the efficacy of the hydrofoil, it has never caught on in the recreational boating market. That may be changing.
In 2018, the Swedish company Candela came out with the C-7. It was the first electric hydrofoil boat on the market, offering a smooth ride above waves up to 4 feet. The more advanced C-8 model made its debut at this year’s Consumer Electronics Show in Las Vegas. Instead of using a Torqeedo outboard, as the C-7 does, the C-8 has Candela’s new C-Pod system: twin motors submerged in a pair of torpedo-like pods that eliminate whirring gear sounds.
Courtesy AquilaStandard hulls have lots of drag. Adding a hydrofoil drastically reduces friction and makes power supplies, such as electric motors, more effective. This increases range and speed. The array retracts when moving into shallow waters, mooring or trailering. At 22 knots, the C-Pod draws 25 kW from the battery, whereas a traditional 27-foot electric boat would use more than 100 kW.
Because of its efficiency, the C-8 uses a fairly modest 69-kWh nickel-manganese-cobalt lithium-ion Volvo Polestar 2 SUV battery bank. It provides a range of 50 nautical miles at 20 knots. Candela’s engineers not only design and build their motors, but they also develop the computer and software needed for stable flight. Six sensors paint a 3D picture of the waves ahead and feed information to electric actuators, which control the angle of the foiling wing.
The C-8 is aimed at high-end, green-leaning boaters, as evidenced by the first 30 Candela buyers also being Tesla owners. “This year, we are making and selling 100 C-8 units,” CEO Gustav Hasselskog says, “so our goal of selling a few hundred a year seems very achievable. About 40% of sales are in the United States. The fastest-growing sector will be public transport on the water, where we’ll offer the Candela P-12 ferry, which can carry 30 passengers at a speed of 20 to 25 knots for up to 60 nautical miles.”
Courtesy CandelaWaveFlyer Volaré
In Australia, the WaveFlyer Volaré is a compact two-seater that uses two electric motors and a host of electronic assists, controlled by a joystick, to make it easy to drive — a must for the rental and luxury recreational markets. This boat has a retractable hydrofoil/outdrive that allows it to be operated as a traditional boat in shallow water. It can also be beached. The standard model has a lithium-iron-phosphate battery pack with a 1.5-hour run time, a 30-minute charge time and a range of a little more than 20 miles. The extended-range model has a nickel-manganese-cobalt battery pack with 4.5 hours of run time, a 1.5-hour recharge cycle and a range of more than 60 miles. Its payload is about 440 pounds for foiling and about 550 pounds for floating.
During the past four years, WaveFlyer hulls have evolved from being offshoots of personal watercraft, catamaran canoes and stepped kayaks to the final stepped trihull design, which helps achieve decent performance in shallow water when going off-foil. According to innovation director Josh Portlock, the first delivery of the WaveFlyer Volaré is expected later this year. He reports millions of dollars’ worth of reservations so far. Geographically, sales interest has been divided 60-40 between the United States and Australia.
Courtesy WaveFlyerAquila Hydro Glide
Maybe the most consumer-friendly use of a hydrofoil is Aquila’s Hydro Glide Foil System, which uses a static metal hydrofoil wing connected between the hulls on the 36 Sport and 42 Yacht catamarans. An upcoming Aquila model is expected to have the Hydro Glide as an integral part of its build.
Designed to lift the hull about 6 inches higher, it doesn’t need sophisticated electronics to keep it airborne. Its purpose is to reduce hull drag by as much as 40%, with a corresponding increase in fuel economy.
I ran performance tests on two Aquila 36 Sport models, one with the Hydro Glide and one without. The kicker was that the hydrofoil boat had 100 fewer horses (Mercury Verado 300s versus 400s) and yet had a 2.4-second quicker time to 30 mph. It was only 1.4 mph slower at top speed. With a full 356-gallon gas tank, at top speed, the Hydro Glide boat could travel 312 miles, while the non-foiled boat could go 204 miles.
Another plus is that the hydrofoil only increases draft by about a foot, allowing the boat to float in just 2 feet of water. The extruded aluminum wing is also stout enough to withstand gentle beaching, which we did during our test. Its V-shape eliminates the all-or-nothing lift of a traditional hydrofoil that can send a hull plummeting alarmingly fast and requires many computer corrections per second to stay aloft. The reduced drag makes the steering lighter and the boat more nimble in turns, which is unusual for catamarans.
According to Aquila brand manager Alain Raas, about 40% of the 36 Sport models have been ordered with the Hydro Glide. Some of those opting out have cited wanting the twin Mercury Verado 400 engine package. (Hydro Glide models are limited to 600 hp.) Others said that because they tended to make short runs, the return on investment wasn’t sufficient to recoup the feature’s $33,000 price tag. Nevertheless, expect to see more hydrofoil boats in the future, especially in the electric boat sector, as prices will drop with greater volume and further advances in technology.
This article was originally published in the June 2023 issue.
