Flux Marine is a US innovator in electric propulsion that first attracted attention when they won two awards, including ‘Best Green Product’, at the 2021 Newport Yachting Festival.

Listen to this article as a podcast:

It is led by CEO Ben Sorkin, COO Daylin Frantin and CTO Jonathan Lord . Sorkin and Frantin have been friends since growing up boating together in upstate New York, where Sorkin would pilot remote control boats around Lake George. Sorkin met Lord at Princeton University, where he proposed a hydrogen propulsion project to a professor. The professor suggested battery electric instead, Sorkin developed the concept enough to get seed funding from the university’s Mechanical & Aerospace Engineering and Flux Marine was born after they graduated in 2018.

Read: Flux Marine lands $15.5M Series A Funding

The start-up was selected for many accelerator programs and received important grants, then raised $15.5 million in a Series A funding round. They originally had three electric outboard models but opted to focus on just one, the Flux 100 HP, which can be programmed for lower and variable power outputs.

Scout one of the first to partner with Flux

Scout Boats of North Carolina was one of the first companies they partnered with to offer electric boat packages and they now have the 215 Dorado and the 215 Sport XSF. Flux also partners with Highfield RIBS (rigid inflatable boats) on their Sport 660 model, and recently added a Tritoon to their model lineup.

I got an invitation from Ben to go out with him for a sea trial on the Scout 215 XSF during the 2025 Miami Boat Show and jumped at the opportunity.

Scout launched the non-electric version of the 215 XSF in 2016 and it and has earned a reputation for being a comfortable, affordable, well made boat. The centre console layout provides a walk around deck that is quite roomy for a fairly small boat. The ‘SF’ in SFX stands for Sport Fishing, so there are plenty of built in rod holders and other features for the avid angler, but there is also lots of comfortable seating that makes this a great all around family boat.

There are a couple of things about it that make it a good candidate for electric outboard propulsion and match up particularly nicely with Flux’s technology.

Optimized weight and hull design

Like all Scouts, the hull is built of 100% hand-laid fibreglass that provides strength using less resin-saturation and helps reduce overall weight. Weight, of course, has an effect on how much power is needed to run the boat, and comes into play with electric boats because weight reduces range. The efficiency of the hull also effects the range, and the 215 has Scout’s NuV3 proprietary stepped-hull design that uses less fuel – whether that be liquids or electrons.

While the weight is optimized, this is still a 21′ 5″ (6.2 m) boat weighing in at 2,775 lb (1,260 kg).

When powered by burning fossil fuel, the usual motor is a Yamaha or Mercury 150. The Flux 100 electric outboard delivers continuous power of 100 hp (75 kiloWatts) and peak power of 175 hp (130 kW) and as I found out on our sea trial, the electric Flux provides all the power you need.

Yes, the 150 ICE motor does have a higher rating compared to Flux’s continuous rating, but the fact is that all of that power is rarely used, and when it is needed the peak capabilities of the Flux 100 HP easily match the speeds the gas motor provides. There is also ample range for the average boater.

We used very little of that power when we first pulled out of the slip for the sea trial, as many of the waters in and around Miami are speed controlled to help protect manatees. That gave Ben some time to tell me the Flux story.

He told me their vision was always to develop something from the ground up, get rid of any preconceptions coming from what already existed – in ICE outboards or electrics – and start with a totally clean slate. The two criteria that everything revolved around were: maximizing efficiency and eliminating any outboard motor pain points.

They were already ahead on the efficiencies, simply by using an electric powerhead as compared to a gas motor that creates a lot of heat and noise, but only converts about 30% of the energy in fossil fuel into actual work.

Flux outboard designed with a clean slate

Outboards usually have other inefficiencies on top of that. Traditional setups have a complicated gear mechanism that transfers the vertical rotation of the drive shaft to the horizontal rotation of the prop shaft. Ben and his team did their analyses and found that a further 15% (of the 30% efficiency) get lost in the cogs.

So the team looked at belt drives. Flux’s electric motor is over 90% efficient and synchronous belt drives are up to 98% efficient. Flux began by flipping the motor on its side to line up with the rotation of the prop shaft, then looked at some intriguing innovations.

One of the challenges of using a belt drive with a high powered electric motor is its ability to handle the high continuous torque. Ben and his team spent years (and a lot of money) developing the perfect belt drive, and he told me they’ve tested it at wide open speed for over 1,300 hours and it has required zero maintenance.

“The average person goes wide open throttle for a small percentage of the lifetime of the boat” said Ben. “So with 1,300 tested hours of wide open throttle, we’re talking thousands and thousands of normal operation hours with no maintenance.”

Their blank slate approach led to another innovation.

If you look at the usual way a belt drive is set up, it is attached to the motor at the top and prop shaft at the bottom with everything encased in a single column.

“One of the really unique things we’ve done is develop a lower unit that has two trucks, two columns, so the belt goes up either side. That opens up the centre so water can flow through.” That not only increases efficiency by reducing water resistance, but also helps with cooling.

The overall Flux cooling system grew out of eliminating the pain point of having to flush an outboard engine, especially engines operating in salt water. “We completely redesigned that” says Ben, “with a closed loop cooling system. Because the lower unit is underwater, it’s almost like we’ve built a heat exchanger. The fluid – it’s similar to the antifreeze liquid in your car’s radiator – is contained in the unit and the water you’re travelling through cools it. No water comes in, so no flushing required, ever.”

Build their own battery packs 

When you consider the extra surface area of the two column belt drive set up, that essentially doubles the cooling ability. With all of these innovations, there was obviously no way Flux could buy standard lower units from other companies, and as they worked on how to build their own, they also added things like a waffled cavitation plate (“using a pretty cool 3D printing technology”) for even better heat exchange efficiency.

A business advantage of building their lower units and midsections is that they have a better handle on their supply chain and are not reliant on any other company, especially other marine companies, to get components.

Flux is also one of the few electric boat motor manufacturers that build their own battery packs. (At Princeton, Sorkin studied batteries in the grad school classes of his Mechanical and Aerospace Engineering program.

The word ‘battery’ technically refers to a single unit, a cell, like a AA battery. Each individual cell has  very low voltage, but they are bundled and connected into ‘modules’ to increase the total voltage, and then those modules are bundled and connected into the full battery pack that we often refer to when we say ‘the boat’s battery’.

Most motor manufacturers give their detailed specifications to battery pack integrator partners who have bought cells from cell providers. Flux buys directly from the cell provider, and Sorkin says they have been able to significantly reduce the cost of making their own modules and packs by investing in their own production and cutting out the integrator mark-ups.

It also allows them to engineer their packs for very high continuous discharge and very low internal resistance. It’s the resistance that is the source of heat, and the Flux packs generate such a small amount of heat that they do not need to be actively cooled.

“Call it a low single digit efficiency improvement” says Ben, “but every little bit helps. And we’ve got boats as far south as the British Virgin Islands, and never had a customer needing to slow down their boat because of overheating.”

Taking the electric Scout out for a spin

So, enough about behind the scenes. What was it like taking the Scout 215 XSF out for a spin?

As I said, we started out in a slow zone, and that part of a boat ride is always an absolute delight in an electric boat. There is almost literally zero noise. There is zero smell of gasoline or smoke. There is zero vibration of any kind. As Ben said, it’s like travelling in a big canoe (but without the paddling exertion and balancing act!)

Read: E-Force 30 foot electric boat perfect for Miami family

Then we took it up to speed. The immediate torque of the Flux 100 makes a big difference on a boat like the 215 XSF, because the time of the wave drag building up and the bow rising out of the water before planing is dramatically reduced. Once on plane we were quickly going 24 knots (28 mph / 45 kmh) with the only appreciable change in noise being the ocean wind whistling by our ears.

Flux has partnered with Garmin on a Chartplotter interface that shows at a glance everything you need to know : RPMs, map, remaining battery, range at current speed, efficiency, and kilowatt hours per mile. With the touch of a button a more detailed screen shows things like thermal information and data on the motor, inverter, battery, DC power, and torque.

I said to Ben that I am the type of boater who likes to look at the water more than gauges and all I really want is an alert if anything is not going right. You don’t have to watch the gauges, he said, but you’re unlikely to get an alert like that. “If something’s not going right we usually see it well before you do and we’ll give you a phone call or text before anything happens.“

He opened up the Flux fleet management app on his smartphone that they developed in house. “This boat in Maine is charging right now, and this boat here, tht’s another our other Scout Demo in Virginia Beach, it’s fully charged. We know where every Flux boat is and how it’s performing and we can see what they’re up to at any time.”

The software also gathers full data on the speed every boat is going, what the state of charge is and other things related to that range issue that everyone likes to talk about with electric boats.

By tracking how far people actually go, how fast they are going for what percentage of time and what amount of electricity they use (versus what they they think they need), the accumulated data shows that most people, on any given outing, use less than 30% of the battery.

As we were cruising along at 20 knots, Ben said the electric Scout 215 SXF could go at that speed for about an hour, and as he knows from his data, most people go fast for a surprisingly short amount of time. For a family that wants to do a bit of fishing, a bit of tubing or water skiing and enjoy time together on the water – without the noise and noxious fumes of a gas burner, this boat fits the bill.

Flux Marine  Scout Boats

See Flux Marine boats for sale in the Plugboats Marketplace

Scout 215 XSF with Flux 100 HP

Length LOA
21′ 6″

Beam
18′ 6″

Draft
6 m / xx ft

Weight (Full)
4000 lbs

Motor Continuous Power
100 HP /75 kW

Motor Peak Power
150 HP /111 kW

Battery Capacity
84 kWh

Top Speed
32 mph / 28 kt

Cruising Speed
24 mph / 21 kt

Range at Low Speed
80+ mi / 129+ km

Range at Cruising Speed

25 – 30 mi / 40 – 48 km

Charging (20% – 80%): 
110 V, 30 amp: Overnight

220 V, 30 amp: 7.5 hours

Level 3: 1.5 hours

 
 

 
 

The post A great combo – Flux Marine outboard and the electric Scout 215 XSF appeared first on Plugboats.