Race on to produce Australia’s first electric jet ski

E Class Outboards, based in Kiama on the NSW south coast and evolving from what started as a project for a retired automotive engineer, is working on building its very first battery-powered jet ski.

Once the technology is tested and proven, the company’s aim is to convert and sell refurbished jet skis featuring electric drivetrains for around the same price as a good-quality second-hand one.

The company already builds and sells a range of battery-powered outboard motors – using refurbished legs from recycled two-stroke outboard engines  – ranging from 3.7kW (5hp) up to 12kW (16hp).

Owner Lynelle Johnson said E Class Outboards hoped to have its first prototype built and on the water for testing in about three months, with the aim of getting at least a couple of hours at mixed speeds out of a fully charged, lightweight lithium-ion battery.

She said the ultimate aim of the project was to stop jet skis going into landfill once their fuel-hungry conventional petrol-powered engines – some burning through more than 40 litres of fuel an hour – had ended their working life.

Johnson said while some riders would always seek the high-speed thrills that only a high-performance jet ski could offer, the reality was that not everyone wanted or needed to push that envelope.

“People say they want high speed to go all day [in a jet ski], but in fact … they’re brutal to ride – they’re hard work,” Johnson said. “It drinks petrol, it’s loud, and it’s expensive, and what, you do some donuts for 15 minutes?

“And when are you ever going to do 120km/h? You need perfectly flat water for that.

“So what we’re trying to do [with the E Class Outboards jet ski] is to give you enough speed and enough range so that it’s a usable thing.

“With our outboard engines, we do get people who say ‘well, I can go to the shelf and go for miles on a tank of petrol’, well, that’s not what we’re offering.

“We’re offering a typical outing, not an extreme outing.”

However, the jet skis will have a temporary performance mode built into them, similar to Tesla’s “Ludicrous” mode that allows owners to tap the electric drivetrain’s maximum performance for short periods of time.

“One of the things we’re developing is a ‘lethal button’,” Johnson said. “It won’t go long, but man, you’re going to go fast.”

At the heart of the electric jet ski will be a DC brushless electric motor able to provide anywhere between 20-50kW of power depending on how it is programmed, and spinning at up to 12,000rpm – twice that of a conventional engine.

While that seems low compared with conventional petrol-powered jet skis, Johnson said the significant weight savings from swapping out a heavy engine for a lighter electric drivetrain would enhance on-water performance.

Another benefit will be the almost instantaneous well of torque that an electric motor provides from almost zero revs.

“One of the major differences [with electric compared with petrol engines] is that you don’t need to get up to a certain number of revs to get all the benefits from the torque,” Johnson said.

“When you’re talking watercraft, and it’s in a hole and it needs to plane, [an electric motor] is much more energy-efficient at getting that boat on a plane.

“It’s not requiring the same energy as a petrol engine, but we may need to sacrifice top-end speed compared to a petrol engine.”

The maintenance-free electric drivetrain can also be sealed to make it completely watertight – something a conventionally engined ski that needs an air intake and regular servicing can’t really do.

The lithium-ion batteries are also quite good at winter layovers compared with other batteries, losing only a small amount of charge over time. How the jet ski’s batteries will be recharged – the electric outboard motors can use a standard 240-volt outlet – is yet to be decided.

Johnson said the batteries were key to the success of electric jet skis.

“The thing to note about this journey – and it’s a new journey – is that the [electric] engines are not the problem,” Johnson said.

“They’ll improve, but they work,” she said. “The problem is the battery, and there’s literally millions of dollars being spent around the world on battery research.

“Tesla has stated the aim to halve the kilowatt-hour cost of batteries.

“So just say you did buy one of these jet skis, there’s nothing that can go wrong with the motor because nothing touches in it.

“...So even if you had this thing [electric jet ski] for 10 years and batteries double in capacity, you could easily just retrofit it.

“It’s really all about the batteries.”

Johnson said E Class Outboards would initially sell complete electric jet skis, with conversion kits potentially arriving once the technology was proven.

E Class Outboards is not the first Australian company to attempt to build an electric jet ski.

The University of Western Australia’s Renewable Energy Vehicle Project has built a foiling version of a jet ski based on an electric prototype first developed in 2015.

That prototype was able to operate for about 20 minutes with two people on board before needing a recharge.