The Gunboat G4 is a fully foiling Tesla

The groundbreaking G4 is fast even on a concrete floor.

Lots of very smart people have been working to develop and produce a reliable, affordable, effective, and lightweight electric/hybrid electric system to be used on yachts for decades! And I’m not going to bore you with the details of all the electric yacht motors that were launched with great fanfare only to founder on the rocks of electrical engineering reality. But after spending a large and fascinating chunk of time with Oceanvolt‘s Janne Kjellman (a very smart engineer from Finland), I’m going to make a not so dramatic prediction: These folks have figured it out.

The sound of speed onboard the fully-foiling Gunboat G4 from Bill Springer on Vimeo.

And the groundbreaking Gunboat G4 that’s just about to literally “fly”  (it looks fast even on a concrete floor, doesn’t it) out of the Dutch boatyard where it was built is making the most of this game-changing technology. And be sure to watch for the full story of the G4 and other disruptive designs that will be running in an upcoming issue of Boat International.

qPBf57LL7rMSL9Hp17PrUC_SaWaAaYzeVt6SfUNnfQ0And I say Oceanvolt has figured it out for a couple of reasons. First, they’ve developed a fully integrated system. They’ve designed everything—the motor, and the saildrive arm, and the batteries, and the solar panels and every detail down to the elegant control lever and all the necessary software and touch screen displays to work together seamlessly with a small onboard generator. It’s a true hybrid system that’s reportedly efficient enough to provide the required power and range that can rival a similar diesel system, and provide all the benefits of electric propulsion—utterly silent running, instant torque, extreme weight reduction, simplicity, power regeneration, and don’t forget “greenness” that—let’s face it—will never be possible with a conventional diesel engine(s) and separate generator system. They’ve even developed a smartphone app that will show you the system’s state of charge (as well as the location of your boat and other useful info) anywhere in the world. Needless to say, Oceanvolt has won its share of awards too.


The company has also been developing this technology for over 11 years, and has high-profile yacht racers and manufacturers using their systems. But even Janne was quick to admit that the power and efficiency they are able to create now wouldn’t really matter if large capacity lithium batteries hadn’t evolved into what’s available today.

“The lithium batteries we have now changed the game,” he says as we chat (happily, a long way from his native Helsinki and my hometown, Boston) in the shade of the Gunboat tent at the Miami Boat Show recently. “They can be light enough to provide huge capacity without too much weight. They can also accept countless deep discharges as well as high-load charging.”

But as a typical Scandinavian, he was also being a little modest. I believe they’ve created an elegantly engineered, thoroughly tested and robust system that may just do for boats what Elon Musk’s ultra-sexy and ultra-smart S-Type Tesla‘s are doing for cars, and now home energy systems too.

Currently, Oceanvolt systems are available in boats such as the beautiful little Blu30

WiUXiEhHjAq1wkcDQkxZX_NCM-3TV-7C7y9y2FvpMIAAnd the Leopard 40 charter cat, among others, that most obviously benefit from the engine’s small size, low maintenance, and “greenness.”

L40-exterior-imageAnd even Damien Seguin’s Class 40 offshore thoroughbred is using Oceanvolt’s systems.

BB-Damien-SEGUIN_1Now that’s what I call an “Engine Room.”

damien_motorBut as I continue to talk to the “disrupters” in yacht design and production, I keep coming back to Peter Johnstone and the G4. By now, you know the drill. The G4 is the first fully foiling cruising cat. It won awards before it was even launched. And the Caribbean racing circuit is all abuzz because in a matter of days, the G4 will cease to be a design “concept” and begin to be a living, breathing, flying new reality that’s scheduled to appear at Sailing Week in Antigua and other races later in the spring.


No question the G4 is going to be a badass-hull-flying-apparent-wind-creating-head-turning-speed-machine. But it’s also going to need some kind of engine for when the wind goes totally calm, right? I mean, you can’t really foil into a slip now, can you? So, what kind of auxiliary propulsion have Johnstone and his Gunboat team called for on G4? You got it. Oceanvolt. It only needs one electric engine with Oceanvolt’s proprietary saildrive arm that gets lowered into the water from the bridgedeck when it’s time to turn into a “power” boat. And the Gunboat team is so convinced Oceanvolt has figured out electric propulsion, they’ve made their 8kw motor (pictured so elegantly and orange-ly below) standard on every new G4 and Gunboat 55 they build. “We can install diesels in the 55,” Peter says with a grin, “but it’ll cost you extra.”

The G4 is truly the Tesla of the sailing world, and yeah, you’re not the only one who wants to see that.

IMG_1583If all those other accolades weren’t enough, the new, fully integrated electric engine from Oceanvolt (actual size pictured above) is all a G4 will need, and it’s small enough, and let’s just say it, pretty enough, to be the centerpiece on your patio table.

And stay tuned. Johnstone’s G4 and other Disruptive Designs will be profiled in an upcoming issue of Boat International.

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  1. says: Jed

    Very well written article.
    What is the weight of these new electric engines? How much lighter are they compared to conventional diesel engines you would find in the Gunboat?

    1. says: Bill Springer

      Hey Jed
      Thanks for the kind words. According to the Gunboat folks, the electric engine (theres just 1!) in the G4 saves over 1,500 pounds. Amazing, right! Can’t wait to see it in action next month.