Swedish company Candela leads the world in the development and distribution of electric foiling vessels, initially for recreational use and now also for commercial applications.
A few years ago, I wrote about the Candela C-7, which Boating NZ experienced on Lake Wanaka. The C-7’s successor is the new C-8, and the boat featured here is the latest version of the C-8 design, the first in New Zealand, for an Auckland owner. Candela has sold over 100 C-8s worldwide.
The Candela C-8 drew plenty of interest at the recent Auckland Boat Show, where it was displayed on its impressive trailer just outside the Exhibition Centre. The alloy trailer with override brakes is part of the package, which allows the 8.5m boat to be safely and legally towed on New Zealand roads. Towing weight is just 2705kg dry.
The C-8, available in three configurations – Day Cruiser, T-Top and Hardtop as reviewed – is a major upgrade on the C-7, with improved software and hardware, a completely new hull design, and a new, much quieter, more efficient twin-motor 400-volt propulsion system. The foil design is also new.
The new model arguably looks more conventional – more boat-like – and the hull benefits from improved hydrodynamic qualities compared to the previous model. It’s light though, just 1850kg, of which 500kg is lithium-ion battery. The upgraded battery, supplied by Polestar, once a performance division of Volvo but now a standalone manufacturer, has a capacity 69kWh.
The boat’s weight has been kept as low as possible, to maximise range and performance. The hull is constructed entirely from carbon fibre, finished in two-pot epoxy paint rather than gelcoat to save weight and provide UV protection. Payload is 640kg (six to eight passengers).
At displacement speeds, the C-8 rides on its stepped hull like a normal boat, but with the foils in the down position and the throttle applied, it lifts off the water at around 15 knots, riding on a single full-beam transverse C-foil amidships and a steerable winged T-foil aft. The foil and wings are carbon-fibre and said to be ten times stronger than steel.
The T-foil also accommodates the vessel’s twin water-cooled electric motors in a streamlined housing between the wings – the C-7’s air-cooled electric motor was at the top of the upright driving the propeller via a shaft, and therefore much noisier. The counter-rotating propellers look almost too small, but they are designed to efficiently convert torque – and there’s plenty – into forward motion.
Inside the boat, it’s all minimalist painted surfaces with black carbon accents, a black cabin top, and a huge canvas sunroof that’s manually operated. The three bucket-style seats across the front are also carbon fibre, complemented by a bench seat further aft moulded into the generous storage locker underneath a sun-lounger that takes up most of the cockpit. All the cushions, including those on the seat, are lightweight and relatively thin to keep weight down while U-Dek lines the cockpit sole.
Moulded steps provide access through the windscreen to the foredeck where the anchor locker is furnished with a Sarca anchor. Somewhat oddly, there’s only a single bow rail and no fairlead. High-quality pop-up cleats are used throughout to ensure clean lines, and there’s a simple fold-down boarding ladder aft on the port side. The pop-off fenders are a clever feature.
The steps hinge up, supported by gas struts, to reveal a good-sized forward cabin, minimalist in concept but with full-length berths and LED lighting, quilted-look panelling and padded ceilings. The cabin can be configured for sleeping or sitting while a toilet, shower, sound system, swim platform, backdrop, sunshade, and underwater lights are C-8 options.
In general, the boat’s vibe is very Scandinavian, with a ‘less is more’ ethos. That’s primarily driven by the need to keep weight down to ensure the C-8 delivers the performance and range customers reasonably expect. So, if you like your boats with lots of toys, the C-8 is not for you. If, on the other hand, you appreciate groundbreaking technology, then the Candela C-8 has plenty to offer. It’s what goes on behind the scenes that is so impressive.
Operating the vessel is easy because, for the most part, the onboard computer takes care of everything. The software is quite a step up from Candela’s earlier models, as is the system’s ability to make minute changes to the foils’ attitude and pitch, up to 50 times a second. The foils are now controlled electrically, rather than hydraulically, as was the case on earlier models, making them much more responsive.
An array of radar sensors monitors the height above the water in foiling flight. The flight controller (computer) uses actuators to make constant adjustments to the foiling surfaces’ angle of attack (including warping the C-foil), to maintain stability and elevation, controlling pitch, roll, and height. The vessel also utilises GPS, gyroscopes, and accelerometers to monitor its position relative to the environment. Optimum flight height is about a metre above the waves.
The user interface (UI) has also been improved, with a large touch screen display providing access to the boat’s many modes and a huge range of operational and environmental information. Automotive-style buttons on the steering wheel give quick access to many of these functions and display modes.
This C-8 belongs to Auckland boater AJ, who intends to commute between homes on Auckland’s North Shore and Rakino Island. Quite how that will work remains to be seen, but one option might be to store the C-8 in a dry stack facility on the mainland and keep the trailer at Rakino Island.
With any electric vessel (as with electric vehicles) range is a limiting factor. In the C-8’s case, the effective range on a full charge is around 50 nautical miles (2.5 hours run time at 20 knots), which is pretty decent. A limp home mode gives 3nm at 4 knots. If you opt for a fast DC charger, charging takes between one and three hours (it’s quick to 80%, but the last 20% takes longer), or 12 hours/overnight on a conventional AC charger.
In operation, a glycol-filled heat exchanger with a cooling plate under the hull cools the battery. When the boat’s foiling, a rooster tail of water is directed onto the plate to carry away heat; at displacement speed, the plate is submerged.
For our demonstration, the C-8 left Gulf Harbour early in the day, its battery charged to 91%. Dominic Lowe, representing Carbon Yachts, along with Rhys Woon from Candela Sweden, then spent time tooling around Rangitoto Island getting video in flat water. Later we rendezvoused with the C-8 off Takapuna Beach, where we picked up the owner for his initial familiarisation session with his new vessel.
This consisted of several runs, multiple stops and starts, and quite a bit of showing off for Boating’s drone camera. After a couple of hours getting to grips with his new boat, we dropped AJ back on the beach. By then the wind had risen to 17 knots and the sea state had also increased, although the C-8 can operate safely in waves of up to a metre high. When we waved them on their way back to Gulf Harbour, the battery was still at 61%, leaving ample charge for the journey home.
Our impression of the Candela C-8 underway was one of smoothness—waves become irrelevant because you are flying above them and there is almost no wake. It’s quiet too with the electric engines underwater, though there is constant aural feedback from the actuators adjusting the foils. But compared to a conventional ICE runabout, conversation on board is easy.
The C-8’s efficient, too, consuming just one kWh per nautical mile at 20 knots cruise speed. Travelling above the water’s surface at 20-plus knots in near silence except for a bit of wind and water noise, the true speed is deceiving—objects and other boats come up quickly, so one needs to plan ahead. Top speed is 27 knots.
The boat turns smoothly when foiling, banking gently under the control of the CPU, but the turn radius is relatively wide – any sudden changes in direction cause the vessel to automatically abort foiling flight, which also occurs if the sea state exceeds performance parameters.
Whether they’re induced by the software or at the behest of the pilot, touchdowns are controlled. Rhys demonstrated this by bringing us to a stop both fast and slow. Fast makes a little more noise as the boat settles abruptly by the stern, while slowly pulling the throttle back results in the C-8 gracefully kissing the water as it transitions to displacement operation.
The Candela C-8 is clearly a much more mature and technologically advanced model than its predecessor. It’s also more practical and arguably better looking. As Candela founder and CEO Gustav Hasselskog explained to us at the show, Candela has pivoted from “a tech company that had decided to build boats to a boat company that employs the latest foiling and electric propulsion technology.” This Candela C-8 for an Auckland owner proves the concept has international appeal, while the company’s focus on its P-12 electric ferry models, one of which is coming here, suggests its future.
