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What if you could change the boat design to achieve double or triple the run times from the same battery?

One of the first questions we get asked is how long does the electric outboard motor run for?

This isn't really a question about the electric outboard motor - which can run all day. It is really a question about the boat's design, how fast do you want the boat to go – and of course how much energy you are carrying in batteries - it's no more complex than deciding the capacity of your fuel tank.

At Eclass Outboards we use a guide of 1kWh per kW of engine power to give one hour at wide open throttle (WOT) or two to three hours at mixed speeds.

One hour at WOT is plenty for the typical electric boat outing. Especially as research has shown that most leisure boats spend around 40% of their time on the water at idle – which with electric outboard motors means no amps are drawn during idle.

And with instant torque available to get the boat moving we find that very little time is spent at WOT with an electric outboard. With an ICE engine, the full HP is not developed until the RPMs reach 5/6000 RPM, so again in the low to mid-range RPMs the electric outboard will outperform the ICE engine, conserving battery.

That said, Lithium-Ion batteries are not currently as energy-dense as fossil fuels. This will change as there are literally billions of $ being spent on R&D in this area.

However, for those wanting longer range times, who don’t have the budget for more kWh in batteries or their boat can’t carry the weight of more batteries, or who don’t want to wait until batteries are more energy dense – what if you could change the boat design to get the run time?

Hydro foiling electric boats.

The first response to a longer and faster run time was the hydro-foiling electric boat. This puts the boat out of the water while planing, dramatically reducing the energy required to propel the boat.

The most spectacular example is the European luxury electric boat maker Candela. The C-8 model makes a claim that with Polestar EV car batteries they will have the longest range in the world. The Candela C-8 will have a range of up to 57 nautical miles, or 105 km, at a cruising speed of 22 knots, or 40 km per hour, which equates to around 2.6 hours of run time at Wide Open Throttle (WOT). Candela says the C-8’s performance puts it on par with powerboats using internal combustion engines.

Eclass Outboards have had a couple of approaches from companies wanting to build hydro foiling boats in Australia. This technology is very expensive as not only is the boat a completely different design, but the computer technology required for stabilization is very sophisticated. However, we are ready to meet the challenge with our Australian-made and affordable electric outboard motors when asked.

Air-cushioned hulls for electric boats

The newest exciting electric motor run time solution, again from Europe, is the air-cushioned hull.

Using technology that has been around for a couple of decades, SES-X Norway has announced they are ready to commercialize an air-cushioned hull. (pictured above: Source PlugBoats) Conceptually this is a cross between a hydro-foiling boat and a hovercraft, reducing the friction between a boat and the water by raising the boat’s hull above the water's surface.

SES-X system hull is a combination of a catamaran and monohull, using the best features of both.

Boat volume provides space for the fans creating the air cushion as well as the batteries necessary for the fans and electric propulsion motors. Sensors collect data as the boat is in motion to adjust the air output from the fan.

These hulls can have any topside installed, so they can be applied to leisure boats, water taxis, work boats, and passenger ferries, however, due to early costs it is expected that ferries, workboats, and luxury 8m leisure craft will be the first vessels with this technology.

This technology could be very exciting as it could be used as an amphibious craft. Again, Eclass would be up for the challenge as we have already been approached by Hovercraft owners and have talked through a solution with them.

Because planing boats powered by our Australian-made electric outboard motors get on the plane early due to the instant torque it is pleasant to cruise at 10 knots on the plane using very little energy and, in some states, don’t require a license to operate at 10 knots or under.

If you have a boat design concept that needs a custom marine electric engine, please get in contact here

Finalist in both Commercial Marine Design and Marketing Awards

We are proud to have been judged as finalists in two categories in these awards.

The 2022 Commercial Marine Project/Design or Manufacturer of the Year award identifies product manufacture, design, and shipbuilding within the Commercial Category in the Australian commercial marine sector. 

The 2022 Marketing Strategy of the Year award acknowledges the success of an innovative and effective marketing strategy implemented between January 1 – and December 31, 2022

As Australia's only outboard manufacturer and only electric outboard manufacturer, we are working at the cutting edge of the marine industry in electric outboards, electric boats, and electric jet skis.

See the AIMEX Link to the Awards

Electric Boat Propulsive Power Explained.

Why kW to hp conversion formulas aren't that helpful in electric boats

One of the first questions people ask us is what horsepower does a kW engine equate to?

And often they have heard of the international hp to kW conversion formula. Which is 1kW = 1.34102209 hp

This is fine, in theory.

However, in practice, we find that calculation is not at all useful.


Because it doesn't take into account the instant torque. And the advantages of electric in the low to mid-range RPMs. The RPMs you actually need to get on the plane or get going - or dock for that matter.

So that's why we refer to propulsive power at the propeller as the important power equation. And why we comfortably say that whatever propellor the ëlectric outboard can drive, that's the hp equivalent. 

So let us explain how this works.

In a combustion engine, the engine has to develop enough RPM (revs per minute) to reach idle speed. This usually occurs at around 1000 RPM, and you are in idle until that point.

Now you can get into gear and start to develop the advertised hp. But the fully advertised hp doesn't occur until the engine has reached around 5/6000 RPMs. So if you are at mid-range, you have not got all the hp of the engine available to you. An example would be a 40 hp outboard, which would only have around 25hp or less available at the low to mid-range of its RPMs.

Now electric outboards behave very differently. They have full power (instant torque) available from the first turn of the propeller. And a flat torque curve.

This power is important in planing boats, as you want to efficiently get out of the displacement hole and on the plane. Then you can reduce power (and amp draw).

In displacement boats, this instant torque gives you high torque at the low range RPMs - perfect for creating that momentum you need to get the boat traveling. The ideal for displacement boat efficiency is to use the biggest propeller you can, turning at the slowest rate.

So back to propulsive power.

When you are looking at electric outboards, we will ask you what propeller your current outboard turns (pitch and diameter). From there we can work out which is the right kW outboard for your boat. By the way all our outboards are made in Australia.

For further information

New report says the industry will be worth $USD 20 Billion

That's the prediction of a report from IDTechEx estimates that “the market for hybrid and pure electric boats and ships will rise rapidly to over $20 billion worldwide in 2027“. 

While EClass Marine has been one of the first manufacturers, and still the only electric outboard manufacturer in Australia, the report says there are now more than 100 marine electric manufacturers worldwide.

These companies are working on everything from electric ferries and new hybrid container ships, to the small kW trolling motors now loved by fisherfolk.

The first electric ferry in the Southern Hemisphere (NZ) had its maiden voyage just last week.

And Outboard giants Mercury and Yamaha have unveiled their first fully electric concepts. Although these seem to be lower kW offerings and not available to the market as yet, it is a sign of the industry direction.

At EClass Marine we think that once the marketing might of the large manufacturers gets behind electric boats, a lot of the skepticism will wash away.

Having said that, there is a lot of work to do for the mainstream adoption of electric outboard motors. Buyers have battery range anxiety (interesting as it is no different from having a fuel gauge and planning your trip), are not used to paying upfront for batteries.

Also, not many manufacturers are producing the 20kW (40hp) and higher electric outboards so common on many craft. EClass has put a lot of work into this segment with our 20kW Ultra electric outboard engine

The report also indicated that access to parts may be a barrier to electric outboard motor adoption. That's why at EClass we are using tried and proven 2 stroke outboard casings. Any corresponding Yamaha part and accessory will fit. No waiting for a proprietary part to be shipped, and a competent marine technician should be able to install it. We have a 3-year warranty on our electric outboard engines for private use.

Revolutionary new charging Bouy for electric boats and electric outboards

For all of you who mock electric boats and say how do you charge out at the reef!

Maersk Shipping has partnered with the world leader in offshore wind generation on a buoy system that will charge the electric outboard batteries and hybrid vessels using electricity from the wind turbines. The first use will be for wind farm service vessels but the long term goal is to use them for boats and ships of all sizes and have a significant impact on the use of diesel fuel.

Eclass Outboards have long believed that solar charging will set electric outboard motors and electric boats apart. We have a portable solar power station Ecoflow DELTA Max that does this job and can be kept on board.
Credit to plugboats

Eclass Outboards has a COVID safe plan lodged with Service NSW if you visit our showroom.

COVID safe QR code checking
Sanitizer available for hygiene and COVID safety
Contactless payment for product purchase

1.5m distancing for product demonstration
Product is wiped down after demonstration for hygiene and COVID safe practices
Mask friendly showroom
Online contactless inquiry and information
Staff sent home if unwell or showing COVID symptoms.

Our staff is fully vaccinated against COVID.

Eclass understands you want to keep yourself and your family safe and well. So we are taking every precaution as we want to see you out on the water enjoying an electric boat experience!

Contact us if you want to book an Eclass Electric Showroom demonstration of our electric outboard motors and Ecoflow Delta Max portable power stations.

See our full range of electric outboard motors. Made in Australia

Friday December 10, 2021. 3pm to 6pm

See EClass Outboards range of powerful electric
outboards 4kW to 30+kW (8hp to 40hp)
All our electric outboard motors are developed and made in Kiama, Australia. We've taken 10 years to design electric outboards for Australian conditions and make affordable electric boats possible
Also the revolutionary EcoFlow DELTA Max portable power
stations and solar for off-grid boating, camping, and
bushfire/emergency preparedness.
Light refreshments, just drop in.
Call Lynelle 0408 360 084

For more information about our products CLICK HERE

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