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sailboat electric engine conversion

Electric Sailboat Motor: Range, Cost, Best Kits for Conversion

Today, owning a completely green sailboat has been made possible with electric sailboat motors.

Imagine cruising with the silence of an electric sailboat motor and the ease of use with a simple press on the start button. What’s better is there are no exhaust fumes at all with significantly less maintenance.

It’s so appealing that a lot of sailing liveaboards have made their electric sailboat motor conversion.

However, some sailors are still on the fence, worrying about the range and price of the electric sailboat motor.

If you are one of them, you are in the right place!

This post will guide you through every aspect you need to know about electric sailboat motors to help you make an informed decision.

Besides, you will get professional insights on how to make the electric sailboat motor conversion for your own boat and learn the best electric sailboat motors (with honest reviews).

Table of contents:

  • Electric Sailboat Motors: Confusion Explained

Electric Sailboat Motor or Combustion Motor

  • Electric Yacht Motor Conversion: Two Solutions
  • How to Size an Electric Sailboat Motor

Best Electric Sailboat Motors (with Reviews)

Electric Sailboat Motor

Electric Sailboat Motor: Confusion Explained

Can you go cruising with an electric sailboat motor? Can you put an electric motor on a sailboat? Are there any limitations?

Whether electric sailboat motors are a good fit for your boat is not a YES or NO question. Here we will explain your top worries with statistics and facts. That way, you can make a wise decision according to your situation.

You may hear some complaints about the batteries and range of the electric propulsion.

However, their experience may not suit electric sailboat motors.

In fact, even small electric engines work pretty well in many sailboats. That’s because most of the time, the wind can power the boat, and the motor is just used for docking or in rare times when there is no wind.

Therefore, it makes more sense to learn electric sailboat motor performance in real-world applications.

Here is a test report of a 3 HP electric sailboat motor on an RS21 racing sailboat:

As you can see, the small electric sailboat motor can run at 5.5 mph top speed for one hour continuously.

And there is a big difference in terms of range vs speed for electric sailboat motors:

If you lower the speed, the range and runtime can be greatly extended. The slower you go, the further you’ll get. For example, if you cut your speed in half, the electric sailboat motor can last 7 hours and go 20 miles within one charge.

That’s pretty sufficient if you use the electric yacht motor mostly for docking or as an auxiliary engine.

Faster top speed (and more range) is available with higher power electric sailboat motors depending on your specific requirements. Contact a specialist to design your electric sailboat motor solutions.

Also, don’t forget to get the electric sailboat motor with regeneration (See recommendations below).

That’s to say, when there is a lot of wind and you’re moving rapidly via your sails, they regenerate and store electric power on the batteries to keep you moving at other times. Solar recharging is also a plus.

Essentially, the range depends on how many batteries you have, so it’s not a limitation of electric sailboat motors but energy and batteries.

If you are still worried, you can offset this by getting a diesel generator, which is more efficient than a diesel engine. And it is a range extender when you need it, but for 90% of your motoring that you don’t need the range, you can rely on the electric sailboat motor.

Some of you might be concerned about the extra weight of the batteries.

In fact, an electric sailboat motor with lithium batteries weighs less than a diesel engine, particularly if you include the fuel weight.

If you want a lightweight electric sailboat motor solution, make sure you get one with LiFePO4 batteries . Compared with other marine batteries, they are more compact in design with much less weight and higher energy density.

Some more advanced electric motors for small sailboats (such as Spirit 1.0 Evo) feature an integrated lightweight battery. So you don’t need to worry about the complex wiring to hook it up or extra space to store the battery.

This is a huge plus if you want to use the electric sailboat motor on a tender or dinghy.

Electric Sailboat Tender Motor

Here is also a chart that collects the weight of some popular electric sailboat motors for your reference:

For many people, another big problem with electric sailboat motors is the cost.

It’s true that a gasoline outboard with similar power is a lot cheaper to buy. However, the electric sailboat motor eventually wins in long-term operating cost. That’s especially the case if you are going to do a lot of motoring.

Electric sailboat motors save on fuel and maintenance costs, which can build up to a large amount over time.

Here is a chart that compares the cost of a 3HP electric sailboat motor (coming with a built-in battery) with its combustion counterpart:

Electric Sailboat Motor Cost Comparison

That’s to say, you will cover the price difference for electric yacht motors eventually as long as you use it long enough. Click to check the details of the calculation .

What makes the electric sailboat motor even more worthwhile is it saves you a lot of hassles, especially for sailors who only use the engine in and out of the harbor. Dealing with the maintenance of the gas outboard for a 10 minute motor out of and into the harbor is disproportionate and painful.

*The higher horsepower electric sailboat motor may be different in terms of the cost calculation. Check out the outboard motor pricelist by HP for more information.

As you may have already noticed, electric propulsion has already been widely used in the marine industry:

It’s quiet while motoring, clean to handle, environmentally friendly, with less maintenance and operation costs.

The electric sailboat motors are easier to use with dramatically fewer moving parts to break and no worries about being a diesel mechanic to deal with the hard pulling start. You can have it always on, so it is ready whenever you need it.

And it makes even more sense in sailing applications:

You don’t really need to motor much if your plan is to actually sail. If you are completely becalmed, you will probably just need to motor at 2 knots to keep making way, which is easy for electric sailboat motors.

If you mostly use the motor to get into and out of the harbor, the electric sailboat motor also works great for you.

You can always charge up at the dock, motor out of the marina (or even motor to your sailing area or race start), then hoist the sails and when you’re through, the batteries are charged again.

The electric sailboat motor is also useful as a backup (kicker) motor in case your system goes down. That’s why you can see people pushing a lot of big boats with small electric motors. (Click to learn more information about kicker motors .)

Personally, it’s really nice to have an electric auxiliary in the boat – no smelly, messy diesel and motor oil to deal with, a much simpler system with less maintenance, and much, much quieter operation.

However, powerboats tend to have much higher requirements in terms of both power output and runtime. In that case, an electric sailboat motor can be hard to satisfy your needs.

ePropulsion electric Sailboat Motors

How Do You Size an Electric Motor for a Sailboat?

As a rule of thumb, you will need approximately 1 HP per 550 lb of the displacement of your boat.

Generally speaking, a 3 HP electric sailboat motor can push a sailboat up to 25 ft and a 9.9 HP motor is sufficient for a 30 ft sailboat to motor at a satisfying speed.

However, bear in mind the horsepower you need always depends on your needs and applications.

It’s better to check the data from real-world tests to decide whether the electric sailboat motor is suitable for your specific needs.

For example, the 9.9 HP electric sailboat motor Navy 6.0 allows you to go at 6.9 mph (11.1 kph) on a 30 ft sailboat, and the range can be extended to 46.4 miles if you decrease your speed to 2.9 mph (4.6 kph).

9.9 HP Electric Sailboat Motor Performance

Click to see more test reports with other electric motor and sailboat combinations, and find the electric sailboat motor that suits you best.

If you are still not sure about the size of the electric sailboat motor for you, feel free to leave us a comment and we will get back to you ASAP with professional suggestions.

Electric Sailboat Motor Conversion

Basically, there are two ways for you to convert your sailboat to a clean and quiet electric drive system:

You can either convert your current vessel to electric or buy an engineless yacht and install an electric sailboat motor on your own.

#1. Repower Your Sailboat with Electric Motor

If you decide to replace the diesel engine with an electric motor, you will need to do a lot of preparations:

The DIY approach requires an electric sailboat motor kit (including motor and controller), batteries, a good level of mechanical ability and basic electrical knowledge, as well as some common tools such as a voltmeter.

You will need to take the old engine out for the new electric sailboat motor installation. It’s not an easy task that involves removing the engine mounts and the drive shaft (dealing with the numerous hoses and cables), taking out the engine, exhaust system, fuel tank, and its attendant tubes, etc.

Remember to balance the boat to avoid listing during the electric sailboat motor conversion.

Then in with the new electric sailboat motor. The installation process can be straightforward if you choose the electric sailboat motor kit wisely (See steps below). Furthermore, you can set up solar charging for your electric sailboat motor with solar panels and charger.

Many sailors have recorded their electric sailboat motor conversion process and experience. Be sure to check them out to get some inspiration. For example, Ed Phillips has documented everything which can serve as a guide for newbies to get started.

Mind you there can be a whole heap that can go wrong in designing and maintaining the electric sailboat motor systems. You really need to be totally on top of it if you want decent performance or reliability.

If you are not that technically inclined, it’s better to talk to a specialist first to discuss your plan for a smooth electric sailboat motor conversion.

#2. Install an Electric Motor in a Sailboat

If you own an enginless sailboat, the electric sailboat motor conversion is much easier for you.

All you need to do is to find a reliable electric sailboat motor and install it in simple steps. The whole process can be easily done, even for beginners. Here we take the popular 6 HP electric sailboat motor Navy 3.0 as an example to show you the installation process:

  • Step 1 : Rotate the clamps or use the screws to fix the outboard onto the sailboat.
  • Step 2: Mount the steering system in the proper position.
  • Step 3: Install the tiller on the electric sailboat motor.
  • Step 4: Connect the batteries to the electric sailboat motor system.

Click to check the video tutorial that guides you through each step of the installation.

If you are worried about aesthetic issues and want higher horsepower options, an electric inboard motor can be a better suit for your sailboat. If you prefer an inboard motor for your sailboat, contact our OEM team to get an electric propulsion solution tailored to your needs.

Note : You might find some electric trolling motors rated by #s of thrust on the market. Actually, those electric trolling motors for sailboats can only provide limited speed and range. If you are heading into the wind, the trolling motors for sailboats are definitely not an ideal solution.

Once you’ve evaluated if electric sailboat motors are right for you, there are a lot of options for electric systems.

Here are some popular electric sailboat motors with positive reviews from customers worldwide. Fast charger is available for all the models recommended to reduce your charging stress.

#1. 3 HP Spirit 1.0 Evo

If you are looking for an electric motor for a small sailboat, be sure to check out the ePropulsion Spirit 1.0 Evo. It’s suitable for large daysailers or small cruising sailboats under 25 ft.

Electric Sailboat Motor Spirit 1.0 Evo

With the Spirit 1.0 Evo electric sailboat motor, you can go 5.5 mph (8.8 kph) at top speed on the 21 ft RS21 sailing boat, or troll for 20 hours continuously at 2.2 mph (3.5 kph) according to our test .

This electric sailboat motor with regeneration allows you to recover energy from the prop while under sail. It will start to generate power automatically when the sailing speed reaches 2 knots.

Electric Sailboat Motor Regeneration Efficiency

As an electric auxiliary sailboat motor, it can also be easily installed on your tender boats or yacht dinghies since it’s portable and easy to transport (with a lightweight integrated battery).

Features You Will Love:

  • Come with the industry-first hydrogeneration capability
  • Direct-drive technology makes it maintenance-free
  • Portable with a 1276Wh large integrated lithium battery for long range
  • Safety wristband keeps you safe in case of MOB
  • Digital operation keeps you informed of the battery status

Spirit 1.0 Evo Electric Sailboat Motor Reviews:

“Great weekend with my 17′ sailboat powered by the Spirit Evo. This is great. Quiet and reliable. Went at 3/4 throttle for about 1.5hrs when taking it back to boat ramp.” – Robert Taylor

“Very happy with our Spirit Plus. Pushing our Kolibri 560 a 750 Kg sailboat, with ease. Doing about 5.8 km/h at 500W.” – Frank van Asten

#2. 6HP/9.9 HP Navy Evo Series

If you want a little more juice on the electric sailboat motor, check out the ePropulsion Navy Series. It offers 6 HP and 9.9 HP models for your selection and it provides sufficient power for sailboats up to 30 ft.

Electric Sailboat Motor Navy Series

According to our test , the 6 HP electric motor Navy 3.0 can push the Catalina 25 sailboat (25 ft) at 6 mph (9.6 kph) top speed, while the Olga 33 sailboat (33 ft) can go at 7.5 mph (12 kph) with the 9.9 HP Navy 6.0 motor.

The Navy series electric sailboat motor also comes with regeneration features which can be recharged with hydrogeneration, wind turbine, and solar panel.

  • Four controls to fit your sailboat installation and your boating style
  • Accompany LiFePO4 batteries (need separate purchase) are more energy efficient
  • Digital display offers real-time monitoring of the power and battery
  • Magnetic kill switch and safety wristband keep you safe on the boat
  • Electric start saves you trouble pulling the cord to start

Navy Series Electric Sailboat Motor Reviews:

“I have a Navy 3.0 with E80 on a Catalina 25 sailboat. It is working well. Currently I am using about 4% battery to go in/out of the marina by boat.” – Aaron Young

“Just finished my 8 weeks sailing journey in the Baltic Sea. The two Navy 3 outboards provide enough power for my 33ft catamaran. The 400W solar panels provided enough energy for engines and all other energy consumed on board with 2-6 persons. The two Navy Batteries provide power for engines and all other on-board electric devices. I never had to use shore power, so totally self-sufficient electric system.” – Martin Hildebrand

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Frequently Asked Questions

  • Quiet and vibration-free operation
  • No exhaust fumes or fuel smell
  • Seamless shifting between forwards and reverse
  • Having only one moving part significantly reduces potential failure points compared to a diesel engine.
  • Zero greenhouse emissions
  • No pollution released into your local waterways
  • Doesn’t scare away your local wildlife
  • Option to be 100% renewable with solar and wind generation
  • No more fuel and oil getting all over you and into your bilge
  • No more need to carry combustible fuels on board
  • Eliminate fuel costs
  • Higher energy efficiency
  • Charge from solar and wind
  • Reduced maintenance cost
  • Replacement components are relatively cheap

While sailing, our motor systems can harness wind power to recharge your batteries. Our display enables you to optimize energy capture by adjusting the braking level in real-time to match the sailing conditions. The amount of regeneration depends on various factors, with the propeller size being the primary determinant.

The motor size required for your boat depends on several factors, primarily the vessel’s size, weight, and operating conditions (such as currents, open sea, tides). User preference is also a consideration. As a rule of thumb, for displacement vessels, 1kW of electric power can replace approximately 3HP of diesel power. This may seem contradictory, but diesel motors are typically oversized to make up for their inefficiency and limited power delivery. 

To assist you in motor sizing, we have developed an electric power calculator to simulate your vessel’s performance. Additionally, we provide a complimentary electrification report outlining the performance capabilities for your specific boat.

We have engineered our motor with retrofitting sailboats in mind, prioritizing ease of installation without compromising on durability or performance. Our free electrification report includes a 3D model illustrating how our motor system fits within the existing footprint of your diesel motor. We provide custom mounting brackets and shaft lengths to ensure a seamless installation.

Electric motors possess comparable power to diesel motors, while offering additional features that make them highly suitable for marine propulsion. They exhibit greater efficiency, typically 2 to 3 times more efficient than diesel motors, enabling an electric motor with one-third the size and weight to match the power output of a diesel motor. Moreover, electric motors can deliver torque across a broader range of speeds and provide full torque from 0 RPM.

Electric motors offer the advantage of seamless bidirectional operation, eliminating the need for a traditional gearbox with separate forward and reverse gears. While certain applications may still benefit from a gearbox, it would only require a single gear, effectively eliminating the inconvenient clunk often experienced when shifting between forward and reverse.

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sailboat electric engine conversion

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Eliminate noxious diesel fumes, the cost of filling up at the pump, and enjoy your sailboat to the fullest with this DIY electric conversion Kit.  The 5KW Brushless Kit featuring a Motenergy brushless motor and a 48V Sevcon Controller that can produce up to 5KW continuous and is often used to replace 10-15hp combustion engines. T his system is best for boats up to 6,000 pounds displacement.

All our systems have reverse on-the-fly and contactor disable features. "Brushless" means that the motor does not have brushes that will wear out over time, nor will it be a dangerous source of ignition for on-board gas appliances. Larger boats may require a higher power AC or brushless motor. In the U.S. and Canada, brushed motors are only legal for marine use if onboard appliances and accessories use kerosene or diesel (not propane or gasoline) due to the potential for internal motor arcing.

The controller has a regen feature than can allow current to be put back into the batteries from the spinning prop while under sail. This depends on your sailing speed, prop design, and may not be possible in all applications, but is an adored feature for those who are able to use it.

Due to the high RPM of the brushless motor, we recommend the  5-10kW  Gear Reduction to improve efficiency, provide proper torque, cooling, and help prevent cavitation. A typical reduction is 2:1, but this ratio will depend on the required prop RPM needed to reach hull speed. Ideal reduction will enable the motor to spin your prop at the hull speed RPM of your prop when the motor is spinning at its max RPM. We program the ME1718 in our 5kw kit to spin around 3000 rpm Max, at 48v. 

What batteries should you use? Most customers are happy with sealed, deep cycle lead acid, sourced locally to save on shipping. Use 4 in series to get 48v, with a 100 Amp Hour capacity minimum. Larger capacity will give a longer run time.

Those of you that are still in the "research phase" of your conversion should visit one of the  Electric Boats Discussion Groups  and talk to others who are doing or have already done electric conversions.

* Please describe your battery pack so that we can program your motor controller to match - then you won't need to ship it back to us. Minimum battery information includes cell chemistry, amp hour rating, overall pack voltage, series cell count and arrangement.

* If you choose not to use a gear reduction, a thrust bearing in line with the prop shaft is required, since most motors are not rated for axial/thrust loads on the shaft. 

* Before you pull your old engine, support the prop shaft for reference so you can properly align the new system.

* A heatsink for the controller is recommended by the manufacturer, and is included in the kit.

sailboat electric engine conversion

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Sevcon Sailboat Kit Instructions

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Included Components    (may vary based on kW rating and parts availability)

  • Motenergy ME1718 Sealed Brushless Motor.
  • Controller: 48V Sevcon G4827 (can also be programmed at 36v)
  • 827 Display for Sevcon
  • ET-134/126 directional throttle  - recommended if you plan to use an existing throttle lever. The  ET Actuator  (included) connects to your existing throttle cable. Optons: ET-134 has a Neutral Detent, ET-126 has a Spring Return. 
  • Wigwag throttle lever - recommended if not reusing your existing lever
  • PB-8 throttle and Fwd/Rev Switch
  • Sealed Main Contactor
  • Finned Aluminum Heatsink
  • Every kit is individually bench tested
  • Complete wire harness with 10ft key and throttle cable lengths
  • Wiring instructions

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Electric sailboat conversion: How my Parker Super Seal went zero-emissions

Ed Phillips

  • Ed Phillips
  • April 5, 2022

Ed Phillips embraces zero-emissions sailing by ditching the diesel and converting his Parker Super Seal into an electric sailboat.


Electricity is generated by the engine hydrogeneration system when sailing

Aiming to do our bit for the environment, we recently made a number of lifestyle changes – and one of them was converting our Parker Super Seal yacht into an electric sailboat with the use of an ePropulsion electric motor.

It has proved a great transition in so many ways, taking our sailing experience to the next level. At first it felt a scary, big step into the unknown, but in fact proved a relatively straightforward job.

Skylark is our eco Parker Super Seal. She is an accomplished sailing boat, quick, safe, and fun. She is a joy to sail, we regularly achieve over eight knots through the water.

Our cruising range is generally the South Coast between the Solent and the West Country plus the Channel Islands and France. We have aspirations to take her round Britain , we just need to prioritise the time.

Skylark is primarily powered by sail, a main and genoa (140%) and a couple of asymmetric spinnakers.

Article continues below…


Electric inboard boat motors: 3 yacht owners explain why they made the switch

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Leap of faith

Last winter we took the big decision to convert Skylark from diesel to electric propulsion. So her motor is now a 6kW electric engine, with a 9kWh lithium battery, both made by ePropulsion. Leisure power is supplied by Totalcool 12V lithium batteries and solar panels .

Was it a crazy or brave step? Well, somehow taking a perfectly serviceable engine out and going to an emerging technology seemed quite scary, especially when it involved drilling holes through the bottom of your own boat.

Interestingly, having done it, we now feel the most complex part was taking the old diesel out and that if you can put together a piece of IKEA furniture you can convert a yacht to electric. We will never look back, nor go back to a diesel.

sailboat electric engine conversion

ePropulsion pod drive 6.0 Evo 1


The 40 year old Bukh engine before removal

Out with the old

Skylark ’s 40-year-old Bukh 10 engine was still going strong, well bedded-in but was getting expensive to run and maintain. And like all diesels it was not exactly environmentally friendly.

Taking it out wasn’t something to be rushed. Getting the spanners into what is inevitably a very restricted space is an art that takes a while to master.

Persuading the embedded bolts and fixings to loosen is not for the faint hearted. However, a little cussing, the odd cut and much WD40 given time to work seemed to do the job.

In a few hours each day over a couple of days we removed the Bukh. The bits we were worried about, the engine mounts and the drive shaft, turned out to be easier than expected.

The numerous hoses and cables felt a bit ‘Forth Road Bridge’ and seemingly endless, although it was a relatively straightforward task. Just painstaking and on occasions painful.

Having taken everything off the engine the next task was to lift it out. At 140kg this was not a light load. We constructed a frame over the boat using scaffold poles, attached a chain hoist and lifted it gently up and out. It was a dream, all went without a hitch.

Once in the air we had the advantage of having the boat on her trailer, so simply rolled the trailer forward and lowered the engine onto a wheeled pallet. Job done.

With the engine out, there was so much space which got even bigger as we took out the exhaust system. This was actually a genuine ‘five minute job’ and revealed a massive space now used for extra stowage.

Then out came the fuel tank and its attendant tubes and more space gained. But most of all was the joy of saying goodbye to smelly diesel.

Next was to fill the redundant holes in the skin of our ship, the water inlet and outlet, the exhaust outlet. That felt good, the fewer holes in the hull the better!


Drilling holes through the bottom of your boat is a daunting prospect

Finally, the ‘Big Clean’! The bilges of any boat are always a bit grimy, but years of oil and muck warranted a really good scrub. Traffic film cleaner worked well as a degreaser, then loads of soap and water – a task made so much easier knowing that it was the last time our lovely hull would be subjected to those yesteryear hydrocarbons. Hurrah!

Finally we had a clean slate and perfect foundations for the new installation.

In with the new

This proved to be so straightforward, despite being a little daunting at first. Just like IKEA kits, with a good read of the instructions and marshalling the right tools we set to with an engineering chum (to bolster our confidence!)

First, we spent a good amount of time planning. Second, we glassed a 50cm x 50cm marine ply pad onto the inside of the hull, as belt and braces to spread the load of the engine fitting. Essential, no. Diligent, yes. We felt it ensures our engine will be safe and securely mounted for the coming decades.

The ePropulsion Pod engine is totally external and is simply secured to the hull with three 10mm bolts. All that’s required is a 66mm hole for the cables to feed through.


Feeding the cabling through the hull from pod to battery

sailboat electric engine conversion

Shaping the mounting plate to the contour of the hull

sailboat electric engine conversion

Testing the pod’s position before securing it

Carefully working out how and where to position the engine took a good amount of time. We cut off the last 15cm of the drive shaft cowling, otherwise our propeller would have been too close to the rudder. The cutting was easy (in retrospect). Shaping the spacer to the shape of the hull so the engine would sit vertically did take time.

In retrospect, a sharper cutting edge, and more confidence, would make it much simpler next time. Engine fitted, next we moved on board to install the controller, the charger, the morse and the control panel, all very straightforward.

Our top tip – place the control panel in an easy to see position with the instrument cluster on the forward cockpit. The data is really useful and benefits from easy viewing while at sea.


Scaffold pole crane and block and tackle were required to lift the new battery aboard

Next came the battery. Our ePropulsion E175 9kWH battery is compact at 52 x 55 x 27cm although quite heavy at 87kg. It fits perfectly on the engine mounts, the load spread by a piece of marine ply, and takes up only half the space of the old engine.

We lifted it on board using the same chain hoist, lowered it gently into the cabin and slid it forward on an old mountain skateboard that I found in the garage. It was so much simpler than we had dared hope.

Finally, connecting it all up was a steady, logical process that needs to be approached methodically, but it’s not difficult. Then, the big switch on. A press of a button and all springs to life.

I still marvel every time I switch it on. Apart from a few lights, there’s little to show or hear! Push the morse forward and silent, powerful thrust results.

Subsequently, we haven’t looked back and will certainly never go back to burning noisy, smelly, dirty, hydrocarbons with all the damage that they do to our fragile environment.


New battery in situ where the Bukh diesel engine used to be

12V leisure system

Prior to conversion Skylark carried two 12V batteries. These worked well for day sailing, charged by the engine when motoring and trickle charge solar when at rest.

However, with an electric engine there is no alternator so power can get a bit short living aboard after a couple of days out, running instruments, charging phones, lighting etc, without a means of recharging power.

A new solution was required and after much experimentation we have gone for two Totalpower 500 12V lithium leisure batteries, one for the instruments and one for the Totalfreeze fridge. This provides so much power and is easily maintained by the Totalsolar 100 solar panel.


The control box and charger in place behind the battery with lots of stowage space still available

Lithium batteries have many advantages. You can use all the capacity, as opposed to around 50% with lead acid and they can run 240V appliances as well as 12V. In-battery data screens provide all information live.

Weighing only a few kg – less than a quarter of the weight of lead acid batteries – they are much easier to use and so much more versatile.

Wind generation

Currently, we carry an experimental 48V wind generator. So far it is proving most successful. It is powerful, quiet, and neatly out of the way.

The great benefit is that on a swinging mooring, or at anchor, it means we rarely need to use 240V. We are continuing our research into which brands to select until we have enough data to make informed decisions.


Skylark on her mooring in Chichester Harbour

Solar generation

We carry two 12V Totalsolar 100W solar panels This means that we charge the fridge battery in parallel with the leisure batteries. We now have much more 12V capacity than we need – and there is now always ice on tap!

Tenders and paddleboards

To complete our eco set-up our tender has an ePropulsion electric outboard recharged by hydrogeneration and solar. We carry a lightweight ThrustMe engine for runs ashore. Even our Sandbanks Style paddleboards have an electric Vaquita motor, enabling us to always get back to the boat against strong winds and tides.


Tender has an electric outboard engine too

Electric sailboat experience

Some people fear running out of power, but it’s not proving an issue for us. Electricity is generated by the engine hydrogeneration system when sailing. Input is around 100W per knot when sailing between 4 and 10 knots, at the cost of 0.7 knots of boat speed. In addition, we have the wind generator and on occasion 240V mains power.

Solar panels charge the 12V system when living aboard. Skylark lives on a swinging mooring and on the odd occasion when we want to charge from the mains, usually before a long passage, Chichester Harbour Master and MDL Marinas supply 240V electricity free of charge to electric boats at four points around the Harbour (an eco practice worth encouraging).

In reality we rarely use more than a small proportion of the engine’s potential. Skylark weighs approximately three tonnes loaded. We normally cruise at about 975W at just under four knots, which gives over nine hours of motoring.


Silent motoring under engine catches others unawares

A full 6kW gives around eight knots for a much shorter time. We lived aboard for three weeks in the summer, charged just three times (as there was very little wind), and never went below 50% on the battery.

Motor sailing back 29 miles from Southampton Town Quay in under 4 knots of wind, with strong tides both with and against us, we used less than half the battery.

Electric sailboat conversion costs

At the time of conversion we’d retired from the commercial world and had been philanthropists for eight years, gifting our time, so cost management was a critical factor. We spent a good deal of time looking at costs, and the conversion has dramatically reduced our running costs. The logic is as follows:

Bukh annual running costs

I’m a reasonably capable with practical maintenance, however the single cylinder Bukh with its quirky oil seals and gaskets, took me days of work, so it was more practical to work with a professional engineer at a cost of around £300pa for parts and labour, fuel was around £100pa, my morse replacement in its last year was £268, and a new 12V engine starter battery at £120 making a total of £788 spent in 2020.

sailboat electric engine conversion

Pod drive awaiting its prop. New skeg just forward protects the drive from grounding

Electric sailboat running costs

The total cost of the engine set up, including engine battery controller etc. was £6,800. The chain hoist cost £35, 66mm drill bit £12, fuel £0 (free electricity supplies in Chichester Harbour) so total installation cost £6,847. This engine should last for decades.

Assuming a conservative write-down over 15 years, this equates to £456pa. Economically, going electric has been a great decision. It costs around half the annual cost of before, and is so much less damaging to the planet.

Electric sailboat liveaboards

Our three weeks away were an absolute joy – silent eco sailing and silent motor-sailing in the many days of calm we experienced this summer. Everyone stops us wanting to know how we do it, as we silently cruise past 38-footers!

sailboat electric engine conversion

Electrical power is generated while sailing

Range anxiety? We are totally over it! We did passages of up to 40 miles in little wind and didn’t use more than 50% of our battery capacity.

We motored from the Solent into Poole Harbour where we spent several days pottering and stand-up paddleboarding, only charging from shore power prior to embarking on our next long passage as due diligence, since the calm weather had limited our wind generation.

We have found that, as with all electric engines, there is a huge amount of torque giving fabulous manoeuvrability and the joy of silent motoring.

At steady speeds she uses very little power, then faster speeds seem to push the effort up on a roughly cube basis. This is great at encouraging us all to be traditional and work with the wind and tides not despite them.

Having an electric engine also totally changes the way one sails, tacking up wind with just 2-300W gives an extra couple of knots and an additional 10° of pointing angle (as the apparent wind shifts), and all this silently. Wow!

Electric sailboat conversion: What we learned

Switching to lithium.

We haven’t found anything to fear and it takes our sailing to the next level. The one thing that took us a while to suss out was how to run our leisure systems as lead acid batteries only last a couple of days with no alternator on hand!

Our learning was to ditch lead acid in favour of lithium, a quarter of the weight and you can use all the battery power, not just 50% of it. We now have so much power that we happily run a TotalCool fridge solar charged.

We will never go back to hydrocarbons. Going electric is such an all-round better experience as well as making a significant difference to the fragile marine environment. Downsides? The only one we’ve found is that folk joke they’re reluctant to race us, as they can’t tell if we’re running the engine!

Looking to switch to an electric outboard engine ? Click here for advice on how to choose the right engine for your type of cruising

Why not subscribe today?

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Sailing Uma

Electric Motor

Please note:.

The following information is in regards to our initial set up. It has been almost 5 years since we wrote this. Many upgrades and improvements have been made since then. All can bee seen on our Youtube Channel. Updated wiring diagrams, specs and photos will be coming soon. In the meantime, much of the below information is still accurate and I’m sure you will find it useful. And the answer to our most asked question is YES, we still love our electric motor!


sailboat electric engine conversion

An electric motor . . .

Is not for everyone..

Lets first take a look back in time when “production” boats became popular in the late 60s early 70s, the intent was to make an inexpensive boat the average family could afford and handle with limited sailing experience and knowledge. As a result, one of their requirements was the ability to move the boat in difficult situations. This is where the “auxiliary engine” was coined. But, for many, it has become the primary means of maneuvering their boat. Yes, there are places in the world you can’t sail, like the Panama Canal. But, there are often alternatives where you CAN sail.

“We have yet to use our motor for more than 30 minutes at a time.”

As of today, November 2016, we have sailed over 3000 miles up the east coast of the United States and through the Bahamas to Haiti. We have yet to use our motor for more than 30 minutes at a time. The majority of use comes when we drop the mainsail and back down on our anchor to set it. Most of our sailing has been offshore. But, we have also sailed on the ICW and recently sailed 25 miles up the Cape Fear River to Wilmington, NC. We have sailed under many bridges, some on set schedules, others open on demand. In all cases, we sailed under. We have found that having a solid plan and the patience to wait for the right weather and tide is the key.After all, we own a sailboat. They are inherently slow. We are not in a rush. We love the idea of being self-sufficient. But, for those who sail with schedules, are short on time, lack the patience to sit out a wind hole, feel the need to power their boat to hull speed, enjoy maintaining a diesel engine, or are just set in their ways, then an electric motor probably isn’t the right choice.

Want to learn even MORE…?

Of course we would love for you to stick around and read this page all the way to the bottom, but, we have tucked in many distractions (i.e. links) along the way. Don’t feel bad if you digress, we know you’ll be back. If you want to just jump feet first into all things “electric sailboat” Electric Seas is a good place to start. It’s a great resources community and features several other electric sailboat stories for you to enjoy.

sailboat electric engine conversion


“My Electric Boats” by: Charles Mathys. 

Although this book is currently on our Amazon wish list, we have not read it yet. But, it is the only one we could find on the subject and, for only $15, it looks promising. If you read it before we do, let us know what you think!

sailboat electric engine conversion

You don’t need a diesel . . .  

For ocean passages..

Many people have written in and commented that an electric motor is only good for day sailors who weren’t going very far each day, and that you need a reliable diesel engine for long distance cruising. But we feel like the opposite is true. Since we don’t have a dock to tie up to and charge our batteries each night, we rely on sailing to recharge our system. The longer we sail and the more sun we get, the more power we make. Because we don’t have a 9-5 to return to at the end of a fun weekend out on the boat, we have no schedules requiring that we make it back to the dock on time, no matter what the wind is doing. So, we feel that an electric motor, depending on your sailing style, can be adapted to any boat. But, you have to be willing to work around the one major draw back, range.

“We have no schedules requiring that we make it back to the dock on time.”

Range is the one major downside to an electric motor. But, with a sailboat, and some adequate sailing skills, we have found we really don’t need a motor as much as we originally thought. For those who do have schedules, the possibility of a hybrid system may work well. It encompasses all the benefits of an electric system with the added back up of a diesel or gas genset rated to supply adequate power for extended motoring. Some companies even offer an electric motor, like this one, that can be installed in parallel to an existing diesel motor. So the majority of motoring is done with the traditional diesel, however for short periods of time, like moving around the marina, the electric drive can be used instead. This also incorporates the added benefit of capturing power from the spinning prop while sailing, often referred to as “regeneration” or “regen”.

Our conversion to electric . . .  

Started with our motor..

sailboat electric engine conversion

We found the motor on ebay.com, knew it worked and that was about it. We chose this specific motor for three reasons:

  • It was rated at 4.8kW at 36v which was adequate for our needs.
  • It was overbuilt for an industrial application. This meant it had robust parts and easy to source replacement brushes.
  • The motor cost us $125! Since this entire “Electro-Beke” project is just one big experiment, we tried at every corner to keep our expenses minimal.

Our motor weighs 110 pounds, which is quite a bit more than its brushless DC siblings like those used in the existing electric boat market. Although it is probably a little less efficient, its components are much more robust and durable. It is heavy duty, low cost and provides adequate power, with the added bonus of being simple and easy to find parts for. The only parts we will likely ever have to replace are the 8 carbon brushes that transfer electricity to the motor armature (the part that spins on the inside). Depending on use, they can last for many years without wearing out, and for about $80 we can buy a complete replacement set to have onboard. That’s it, virtually maintenance free, with only 1 moving part, the motor itself is relatively simple. On our boat, simplicity is often the defining factor for equipment selection.

This motor happens to be wired with separately excited field and armature (or SEPEX). It just means that we have a lot more control over the motors power output. We can tune it down to have more low end torque, or up to gain high end speed. This will allow us to customize the power output we need for our specific boat. A few other types of motors out there include, Series , and Permanent Magnet that only have one set of coils. Each type has its own benefits and drawbacks. But we won’t get into any of that here. If you would like to know even more about DC motors, click HERE .

we didn’t buy new . . .

Because we received quotes from three different companies:.

  • Here’s our quote from OceanVolt for their AX8 motor.
  • Here’s our quote from Annapolis Hybrid Marine for a Thoosa 7000HT motor. Read their prediction for power consumption and battery drain.
  • Click here to see some data and predictions from Electric Yacht for their Quite Torque 20 motor.

Our entire set up . . .

Cost us just $1,400..

As you can see by the above quotes, The motors and supplementary wiring are all in the $10,000 price range. That doesn’t include a battery bank. Our motor and wiring cost us just under $500. Many of our components were refurbished, used or salvaged from boats being demolished, including some of the wiring. The battery bank and additional tools, like wire crimpers and cutters were another $500. So, for about $1000, we installed our Electro-Beke system. Our charging system ended up costing us only $400 thanks to a few amazing companies who joined our Uma Angels Family and supplied the major components. Find out more about our charging system in the “Charging” section below.

That Breaks down to:

$500 _ for the motor, controller and supplementary wiring. $500 _ for the batteries. $400 _ for the solar charger, panels and bimini modifications.

Power required . . .

To push our boat and yours..

Our motor has an 8hp rating. For those accustomed to gas or diesel engines, this may not seem like much power. But, the rating systems used for gas engines and electric motors are so different that comparing the numbers is almost meaningless. It comes down to the way the two types of motors use their energy and torque curves, which is quite different. According to the research we have done, a 1 hp gas (or diesel) engine can push 500 pounds of displacement to hull speed in calm conditions. Now, the sources disagree a little here, but as a rule of thumb a 1hp electric motor can push about 3 to 3.5 times more displacement than its petrol equivalent. So a 1hp electric motor, drawing 750W, can push about 1500 pounds of displacement.

“Hull speed’ and ‘redundant power’ weren’t something we worried about in our system.”

Our boat displaces 13,500 pounds. so, 13,500 / 1500 = 9hp electric motor., now 1hp (of electric) draws about 750 watts. so, 9hp x 750w = 6.75kw electric motor..

At 48V, our motor should give us 6.3kW, which is slightly less than what we would need to push our boat to hull speed in calm conditions. But that is something we never intend to do. It takes a lot of power to push a displacement boat to hull speed. So the slower you go, the greater your range will be. However, it takes a long time to cover that distance. So, there is a sweet spot right around 4 kts (see graph to the right) where you make good headway, while being conservative with your power consumption. Of course, these are merely suggestions. Real world conditions are rarely perfect and adding 30% redundancy is often recommended by many motor companies. 

We only use our motor for close quarter maneuvering where sailing isn’t an option, like a marina, or tight anchorage, so “hull speed” and “redundant power” weren’t something we worried about when designing our system. We often sail on and off the hook and choose places to anchor with few boats around. 

Power | Speed | Range

Hover over any point to see exact data. For example, it is estimated that at 2.7 kts our motor will draw 600 watts (blue), giving us a range of 65 nautical miles (grey). This graph is based on a 14kW Lithium battery bank and a high end motor/controller combo.

Here are some great companies . . .

That install, sell, or can help answer your questions..

Thunderstruck-EV  and EV-West  are staffed by great people who would love to hear from you and help answer any questions you may have. They both offer DIY kits that will suit the needs of any boat. They can also help source adequate battery banks, help with solar and even find local experts to assist with installations as well. 

If you’re looking for a more “plug and play” set up, check out the companies below. They represent the best in the industry and will gladly customize a set up for your specific needs and provide a detailed quote.

sailboat electric engine conversion

Elco Motors


[email protected]

1 (877) 411-3526

sailboat electric engine conversion

Oceanvolt SEA


[email protected]

+358 10 325 5281

sailboat electric engine conversion


[email protected]

+1 (410) 353-4348

sailboat electric engine conversion

Electric Yacht


[email protected]

1 (855) 339-2248

sailboat electric engine conversion



[email protected]

+1 (805) 455-8444


Here is another great article about “How much electric power do you really need? !!! !!!


sailboat electric engine conversion

Getting down to the Nuts and Bolts

For the complete parts list and wiring diagram, scroll down..

There is a lot to talk about here. Hopefully you can follow along and not fall asleep. Like…I …….am…….right….nowwwww(yawn)www…  SLAP !!! Ok! I’m awake. Where was I. Right, wiring.

With no degrees or formal training in electrical engineering (and no, they didn’t teach us this stuff in architecture school), we had a lot of learning to do. Here we were, with a big heavy electric motor we knew nothing about, a boat it could theoretically push and the dream it would all work in the end. Now all we had to do was figure out how to get the motor to spin the prop. Sounded simple enough…right?

“…all we had to do was figure out how to get the motor to spin the prop.”

This step, of course took the longest. Since all our components were used, refurbished or salvaged, we had to test everything. We then started wiring the system in pieces in the salon and testing those. We then modified, adjusted, replaced and fabricated new systems and tested those. In all, it took us 9 months from motor purchase, to moving boat. Granted, not all of that time was devoted to installing the motor. We did have a few other projects on the side.

There are four main sections to our electric motor installation:

  • The motor controller
  • The batteries
  • The wires that connect it all together

sailboat electric engine conversion

The motor we talked about previously. In all honesty, the main concern when sourcing a motor, is that it has enough power (watts) to push your boat to the speed you would like. The second concern is that it will work with the voltage of the components you choose. 12/24/36/48/72/96V are all common. The general rule, is that the higher the voltage, the fewer amps need to be pushed through the system to attain the same wattage. With this in mind, we have found that 72/96V systems tend to be more expensive than similar 48V set ups and, pushing a boat requires much less power that pushing a car. So, we’re not worried about running hundreds of amps through the system. Although rated at 36V, we run our motor at 48V so we can utilize available golf cart components for the rest of our systems, which are also inexpensive and abundantly available. For our boat, we designed the system to handle 150 amps. This would give us a theoretical output of just over 7kW (48V x 150A = 7.2 kW). If you were paying attention earlier, you might notice that our motor is rated for only 4.8kW at 36V. That is a continuous rating however. It can handle more, but cannot sustain it for long periods of time without some external cooling system. But, because there are times when we need all the power we can get, like stopping or backing down on the anchor, we decided to run our system with a higher amperage rating to accommodate that need.


(As usual, click to enlarge)

sailboat electric engine conversion

The Motor Controller

This little box is the heart of an electrical conversion. Similar to the head of an ICE (internal combustion engine), it controls the speed at which the electric motor spins. It does this by breaking up the power stream coming in from the batteries into tiny little pulses. This is called Pulse Width Modulation or PWM. There are many different types of controllers out there. In general, if you found a motor with standard voltage range, there is a controller on the market that will work for it. Some are more complex than others. Some offer built in regen capabilities, while other require computer programing and digital displays. 

Our controller is a Curtis 1209B. It is designed to run a series motor, but since we got it for such a good deal, we made it work with ours by only using it to power the armature. See the wiring diagram below for more details. This controller is not fancy. It is weather proof, simple and robust. If you haven’t figured it out by now, we love simple and robust. 

The Batteries

We will explain more below in the “BATTERIES” section. But for now, as long as you can create a battery bank that can be wired to produce the required voltage for the rest of your system, then you’ll be fine. Also keep in mind how much space and weight the bank will require. Ours fit perfectly where our old fuel tank used to be and helped offset all the weight we lost by removing the tank and the old diesel motor. For typical lead acid banks,  at 36V you will need 3 -12v or 6-6V batteries. A 48V bank will require 4 or 8 respectively and so on. Although you can purchase massive deep cycle batteries with equally large aH ratings, we don’t see the value of them since it is very difficult to maneuver them into tight spaces on a boat. Ideally, if you can afford them, a lithium bank would be the best for an electric motor conversion. We’ll talk more about them in the “WHAT”S NEXT” section below. 

All our wires our tinned copper or “Marine Grade”, although, we despise that term since it often just means “more expensive.” The majority of which, we scrapped off of boats that were being demolished at the boatyard. What we couldn’t find for free, we purchased from a local discount marine store that sold surplus marine components. This allowed us to spend very little for all the wiring. 

For the most part it is all oversized, but when it comes to wire, the bigger the better. There are many useful online calculators that can help give an idea of what size wire will be appropriate for a given application. If your wiring is undersized, the system will lose some efficiency. For the most part this is of no concern. However, in extreme circumstances it will heat the wire to the point of melting things. For example, we undersized the cables connecting the motor controller to the armature, after a 15min full power test at the dock, we melted off the heat shrink tubing on the terminal lugs. It was quickly replaced by something much more beefy and hasn’t been a problem since. 

O yeah, One More Thing . . .

The motor mount. .

Oops, almost forgot. Somehow we had to keep the motor inline with the transmission and securely mounted to the boat.  We built and re-built 6 different mounting brackets prior to the one we have now. Each being fabricated after hours of sketches and models were developed. We didn’t have to modify the motor any or the transmission itself. However, we did modify the original transmission adapter plate that was used to attach it to the back of our Westerbeke.  We then securely attached the transmission to the hull of our boat. This allowed the motor to float in front of it, leaving the transmission to absorb any thrust from the prop. 

We fabricated the brackets out of steal since it is easy to work with and weld. Once we settled on a final design, we epoxied and painted the brackets and motor with engine enamel. We’re quite pleased with the final outcome. All the exposed metal is protected from corrosion and it is very securely mounted to the old engine pan.

In tandem to our bracket iterations, were several attempts to connect the motor to the transmission. Our early versions were poorly aligned causing horrible vibrations that in turn produced noise. Noise was something we were trying to avoid by going electric. The final design paired two identical sprockets, connected inline by a #50 double roller chain. This seems to work quite well. It allows for small misalignments and produces the least amount of noise. There are of course many other options out there, and someday we may experiment with them. But, for now, this set up works for us. 

Take a look through our Electro-Beke playlist on Youtube  for video of the installation process. 

sailboat electric engine conversion


Including complete parts list..

Here it is. The schematic you’ve all been requesting. You may notice that it is drawn for a direct drive system, where the motor is used to electronically shift from forward to reverse. We have since installed our motor in front of our old transmission and no longer need the Fwd/Rev circuit. However, since the majority of set ups out there use the motor to achieve Fwd/Rev, we wanted to show our diagram depicting a similar set up. If you end up with a Series or PM motor, you should be able to modify this diagram by excluding the 12V bank to motor connections. However, many of the components, like the contactors, require a 12V supply to operate their solenoids. So you will still need a 12V accessory bank. This is often the house bank of a boat, since many smaller boats run 12V house banks anyway.

sailboat electric engine conversion

Below are the components we used, why we chose them, where to buy them and pictures of them installed in our boat. If you didn’t figure it out already, their letters correspond to the diagram above.

(A) – 10A FUSE 

sailboat electric engine conversion

Buy one HERE .

This is a simple automotive fuse held in an inline fuse holder. It protects the ignition circuit wiring from drawing too much amperage in the event of a short.

(B) – Key Switch

Buy one here . .

The key switch is mainly for security. It can be replaced by a simple on/off switch, but taking the key out will slow down someone trying to leave with your boat, without your permission.

(C) – FWD/REV Switch

This switch is only needed if you are planning a direct drive system. We no longer have need for it, but also have yet to rewire our system after we installed the transmission. It is a basic rocker switch with an on/off/on rocker and 6 pins on the back. This allows both positive and negative wires to be switched. We also wired ours so that it will shut off the contactors if switched accidentally while the throttle was engaged. That way it wouldn’t cause any damage to the motor.

(D) – Throttle

sailboat electric engine conversion

The throttle tells the motor controller how much power to send the motor. We chose this one because it allowed us to keep our existing throttle lever and cable mounted on the steering pedestal. It also has a micro switch that we use to close the secondary contactor (N) on the 48V side and the Fwd/Rev contactor (E) on the 12V side when the throttle is pushed forward. This ensures no voltage is going through the system until the throttle is actually engaged.

(E) – FWD/REV Contactor

sailboat electric engine conversion

This, again, is not needed if you, like us, install the motor with a transmission that handles Fwd/Rev. However, if you are planning a direct drive set up, and the controller you chose doesn’t have a Fwd/Rev circuit, then this is a necessary evil. The one we used, we scrapped off an dead windlass. It works great for the 12V circuit and are easy to find.

(F) – Main Battery Switch

sailboat electric engine conversion

Our boat came with this switch installed already. We simply rewired it slightly to accommodate our systems. For now we only use the “Battery 1” and “off” settings. However, if we eventually install a DC-DC converter to bring our 48V bank down to 12V we could wire it to the “battery 2” position as a back up battery bank.

(G) – Positive Buss Bar

sailboat electric engine conversion

Pretty basic here. A buss bar is used to connect multiple leads to the same source. This one is beefy to handle high amperage on the positive side of the 12V circuit.

(H) – Negative Buss Bar

Same as the Positive buss bar above. However this one is tied into the 48V circuit. 

(J & M) – Shunt

sailboat electric engine conversion

These are pretty standard. They are required to hook up an amp meter and measure how much amperage is running through your system. Often an amp meter will come with its own shunt. They sample the current so that not all 100+ amps are running through a meter. That would be very dangerous. Just make sure the shunt and meter are rated for the same mV, usually 50mV or 100mV.

(K & U) – Main Fuse

sailboat electric engine conversion

These fuses protect the wiring in the system. The closer to the battery bank the better. The fuse on the 48V side is rated for 200A and the 12V fuse is rated for 80A. These are rated for amperage only and can usually take a variety of voltages. Both fuses and holders are identical. They just have different ratings.

(L) – Primary Contactor 

sailboat electric engine conversion

This contactor is wired to the main key switch. It is a bit redundant but shuts off any power from the controller, motor and gauges. It acts more like a battery shut off.

(N) – Secondary Contactor

sailboat electric engine conversion

This contactor supplies the motor controller with the power it needs to run the motor. It is also the one that is bypassed by (T) the pre-charge resistor. Contactors are just big remote activated switches. Like breakers, they activate very fast to eliminate high amperage arching.

(P) – Motor Controller 

sailboat electric engine conversion

The motor controller we chose works for our application, but there are many out there to choose from. Do your own research here before deciding on what motor you will use. We happened to get a sweet deal on ours so we made it work with our motor. Our system would be less complicated if we used a controller designed for a SEPEX motor. The Curtis 1209B that we have is designed for a Series motor, but we make it work.

(Q) – DC Motor (SEPEX)

sailboat electric engine conversion

Sorry, you’ll have to find this one on your own.

Since another motor like ours has yet to show up again for sale online, we can’t really recommend the same one. However, the basic idea is finding a motor with the appropriate wattage to push your boat. Refer to our “Power Requirements” section to get an idea of what that might be. Then just make sure it will produce the desired power at a voltage that you would like to work with. We recommend 48V for most applications for reasons described previously.

(R) –  Amp Meter

These attach to the shunt (J & M) and show you how many amps are running through the system. Depending on where it is placed it can either read the amps being drawn from the battery bank or the amps going to the motor. We decided to read the amps being drawn from our batteries.

(S) – Volt Meter

This meter does not require a shunt. As long as the negative lead makes its way back to the negative buss bar, the positive lead can be attached at any point along the circuit. We chose again to read the battery bank voltage with ours. However, it can also be place on the motor to read the voltage there instead.

(T) – Pre-charge Resistor 

sailboat electric engine conversion

They look like THIS . 

There is no specific item to show you here. Each controller and each set up is different. But, I can tell you that the pre-charge resistor is very important. It by-passes the main contactors and supplies the motor controller with the power it needs to pre-charge, so its ready when the main contactor is switched on and all that amperage comes rushing in.

Make sure you check out SV Bianka’s page for another detailed blog about his electric motor installation.For another great article about all the other stuff that goes into a motor installation,

you might want to read “Balance of System” . The article is for an electric motorcycle set up, but the basics are similar enough.

sailboat electric engine conversion

One thing we learned very early on was that . . .

Volts (v) x amps (a) = watts (w) or v x a = w.

At first we thought (please don’t laugh we were total newbies)  that if we took 4 – 12V batteries with 125aH, and wired them in series, we would get a 48V bank with 500aH capacity. Obviously we forgot everything we learned in high school algebra. We soon resolved our mistake and learned that this formula is at the heart of everything electrical. As you can see, Watts are the thing you need to pay attention to. Remember high school physics? W=Work. Many appliances in your house, often things that produce heat, are rated in Watts, but marine stuff tends to rate things in Amps. Well, for our sake Watts are king. No matter what boat you have, it requires a certain amount of work (Watts) to push it through the water at any given speed. So, your job is to charge, store and supply to the motor a similar amount of wattage in order for your boat to move. The more watts you can store, the longer you can push your boat.

“The more watts you can store, the longer you can push your boat.”

As mentioned before, our motor is a SEPEX motor. This meant that the field and armature needed 2 separate voltages in order for the motor to spin. The way we solved this problem was with two separate battery banks. The field is powered by the house bank at 12V. This bank consists of two deep cycle batteries wired in parallel giving us about 250Ah at 12V. So far, it has held up great. It powers everything onboard including the inverter and laptops. We use about 30Ah on a slow day at anchor, and around 70Ah when sailing or when we’re both using our laptops all day at anchor. The nice part, is that even on a cloudy day, our 480W solar bank can replenish that before dinnertime. But we’ll talk more about that in the next section, “CHARGING” below. 

The motor bank consists of 4 – 12V deep cycle batteries wired in series giving us about 125Ah @ 48V. This may not seem like much, but in the last month of sailing, we have logged over 1000 miles, including sailing 25 miles up the Cape Fear River, and have never depleted the motor bank more than 35%. That works out to drawing only 44Ah used. We’ll talk more about range and testing below in the “TESTING” section. 

There are many types of lead acid batteries on the market. Don’t get too invested in brand. Most of the batteries on the market today are made by the same two companies. Trojan seems to be the brand of choice for many. We found batteries for sale locally and for $100 each, including delivery, we couldn’t pass them up. We also knew that the flooded lead acid bank we installed is only temporary. Like we’ve said before, this whole “Electro-Beke” thing is really one big experiment. We have plans to install a LiFePO4 bank soon enough. But we’ll tell you all about that in the “WHAT’S NEXT” section below.

There are many inefficiencies in electrical systems, like heat. However, don’t worry about them too much. If you budget 30% power redundancy into your system, it will more than cover any losses from heat, or mechanical friction and so on.

Check out www.batterystuff.com . They have useful calculators for battery banks and solar, along with great information on different types of batteries and what they are used for.

sailboat electric engine conversion

Our Solar System . . .

Also doesn’t include pluto..

We have 480 watts of solar. Broken down into 2 – 240W panels at 24v wired in series to give us a nominal voltage of 48V. Did you get all that? Great! Steven, from Solar EV Systems , gave us a great deal on them, landing him a spot in our Uma Angels Family . There are a several types of solar panels, but as far as we can tell, any modern panel is efficient and well made. None are much more efficient that others, it’s more about the size of your mounting space, and the size of your wallet. The ones we have are made by Trina, They are not expensive, look well made and perform exactly as promised.PV (Photovoltaic, aka solar panel) modules have three different voltage ratings that are handy to understand:

  • The nominal voltage of a panel could also be called the “conversational voltage.” When we talk about the voltage of the panels and the other components of the system, we’ll most often use the nominal voltage. Nominal voltage actually refers to the voltage of the battery that the module is best suited to charge; the term is a “leftover” from the days when solar panels were used only to charge batteries. The actual voltage output of the panel changes as lighting and temperature conditions change, so there’s never one specific voltage at which the panel operates. Nominal voltage allows us, at a glance, to make sure the panel is compatible with a given system without having to look at the exact voltage. Our panels have a nominal voltage of 24V. We wired them in series which gives us 48V. It reality, they put out about 75V on a sunny day. But our charge controller allows us to charge a battery bank from 48V all the way down to 12V with the same solar panel set up. We’ll talk more about our charge controller later.
  • The second voltage rating is the maximum power voltage (Vmp). This is the highest voltage the panel can produce while connected to a system and operating at peak efficiency. As mentioned above, the max our panels will produce is around 75V, even though we talk about them as a 48V panel system.
  • The third voltage is open circuit voltage (Voc). This is the maximum voltage that the panel can produce when not connected to an electrical circuit or system. Voc can be measured with a meter directly contacting the panel’s terminals or the ends of its built-in cables.

Panels also have two different current ratings: current at maximum power (Imp) and short circuit current (Isc), both listed in Amps. The maximum power current is similar to Vmp: it’s the maximum current available when the panel is operating at peak efficiency in a circuit. Ours can produce 35Amps at max efficiency, They consistently produce 30A on a sunny day and we’ve seen as much as 32A. Similar to Voc, the short circuit current is the current measurement your meter would show when in contact with the positive and negative terminals of the panel while not connected to a system or load.All these voltage ratings and current ratings are often found on the back of a panel. Use them to estimate how much power they will be able to produce.

Two rules of thumb:

  • 1kW or solar will produce 4kWh/day
  • Rated Watts / 3 will get you approximate Ah/d @ 12V.

So, according to this, our 480W panels should give us 160aH on an average day, which we’ve found to be quit accurate. Although, we’ve only ever needed more that 100Ah of charge on one occasion. So usually, our batteries are charged back up before lunch, and we spend the rest of the day on “float” charge.

Types of Panels


These are single silicon cells grown into larger crystals, then cross-section cut into small wafers to form individual cells that are later joined together to form a solar panel. This cell type has high conversion efficiency which means it takes up less space on deck. These cells are generally not shadow protected and are often more expensive per watt.

Multicrystalline (Polycrystalline)

These cells are also single silicon cells constructed by utilizing multiple amounts of smaller crystals to form a cell. This cell type has very high conversion efficiency but is also not shadow protected. Although, you should really be installing any panel so it doesn’t get blocked by shadows throughout the day. It will drastically increase the output if you install them in a proper location.

Amorphous silicon

These are the most inexpensive to manufacture. They are produced by depositing an active silicon material on various substrates like stainless steel sheet. The conversion efficiency is not as good as the single crystal type, but Uni-Solar panels are this type of panel and are shadow protected. Shadow protected means that a panel continues to charge when part of the cells are in a shadow, like a stay, which is a great advantage on a sailboat.

Our Charge Controller . . .

Is at the heart of it all..

The next, and possibly most important component in our charging circuit, is our Midnite Solar KID charge controller. This thing is amazing. Midnite also joined our Uma Angels Family when we asked them to send us a controller and they agreed. We spent a lot of time researching solar charge controllers and learning all about PWM vs MPPT. Bottom line is, if you can afford it, get the MPPT controller. We chose the Kid because it’s just the most efficient at collecting power from your panels. It is also easy to program and understand. We currently run it at 12V and just rewire our motor bank to 12V when we need to charge it. However, we will soon be adding a smaller, simple 12V charger to the “load” circuit of the Kid. This will allow the Kid to be permanently charging the 48V house bank. But, when it is full, switch over to the “load” circuit and charge our house bank through the smaller controller. It may all sound too complicated now, but once it’s installed and working, we’ll be sure to share everything with you in more detail. 

“We have never gone 24hrs without fully charged batteries.”

On a boat, where space is at a premium, you need all the efficiency you can get. Right now, I’m sitting on the boat, it is overcast and raining outside, it’s noon and we’re getting around 100W of power in from our panels (about 8-9A @ 12V). Our house bank will be charged back up by dinnertime, same as the last few days, and we haven’t seen the sun all week. When it is sunny, our house bank is usually charged back up before we wake up in the morning. No we don’t wake up THAT early, usually around 10am, but seriously, if it’s sunny in the morning, we put 30+aH into our batteries before 10am. The charge controller runs silently, however it makes a tiny click when it switches from “resting” to “BulkMPPT”. Since on a boat, we’re attuned to every tiny sound, we usually here it click on and off a few times before the sun even rises. Mind you, it’s only putting in 0.5aH then, but still, the sun isn’t even over the horizon yet and we’re already charging our batteries. 

Check out “Step 26” when we install our solar panels and charge controller. 

The rule of thumb we used when designing our system is that 1 – 100W panel can charge a single deep cycle battery from 50% discharged in a single sunny day. So we have 6 batteries, so ideally we would have 600W of solar. Now, that just wasn’t practical for us, so we settled for 480W and it keeps up just fine. However, if we discharged our motor and house bank down 80% we would need about two sunny days to get them both topped back up fully. Or, about 4 rainy days. For us, this isn’t an issue since we typically use the motor for very short periods of time right before anchoring or when setting off for a multi day passage. So, by the time we need them again, their both fully charged and ready to go. If not, we’ll just hang out and drink a beer. So far it’s never been an issue or even come close to it. We have never gone 24hrs without fully charged batteries.

Many have suggested we have a small generator on board as a back up, just incase there is no sun for many days and our batteries are dead. So far, we have gone a full week without sun and our solar has kept up just fine. Although, we may design a system with the ability to be hooked up to a genset for extending motoring, like say the Panama Canal, so that if we ever needed to, we could just set a generator on deck for a few days and then get rid of it as soon as we’re done. But, for now the whole point was to get away from petrol dependance. 

So far, solar is our only means of power production. We do have plans to get working regeneration from the prop while sailing. The possibility is definitely there, and we have tested for voltage while sailing. But as of today, we haven’t hooked up a charge controller to it. Mainly because we just don’t need it…yet. Our power requirements are so minimal and we use the motor so little, that we haven’t bothered to hook it up yet. But, it is on our short to-do list. So stay tuned for future updates. 

HERE is a link to a great forum talking about solar systems, battery banks and how to balance them. 

sailboat electric engine conversion

How far can you motor? 

Maybe the most asked question we receive..

It’s a valid question for sure, and one that many have asked us. But, we have yet to find out. We are still early on in our testing phase of the experiment. We’ve used the motor many times but rarely for more than 10-15 min and never more than 30. It is also hard to find “ideal conditions” to test in. There either isn’t enough space, time or light. Or the tide and wind aren’t in our favor. Sounds like excuses we know, but it’s the truth. 

“We are in no hurry to go anywhere,  ever.” 

From what we have done, we can tell you this. Our max speed has been right at 4kts. but it was against a slight current, maybe 1kt max. So, that would mean our theoretical top speed is closer to 5kts. 

Here again, we haven’t actually found out. Mostly because without a tow boat right beside us, it would be dangerous to run out of power in the middle of a channel or bay where there are “calm conditions”. But, we’ve motored for 2 nautical miles at 3kts (with a 1kt tide in our favor) and it drained our batteries down to 70%. So, that would mean that in “ideal conditions” we could motor at 2kts for 6 nautical miles. Doesn’t sound like much, we know. But, with a favorable tide and even a slight favorable wind, we can extend that tremendously. We also wait for the wind and tide to be favorable and then just sail to where ever we need to go.

With limited area to mount solar panels and without a genset, we knew if we used more power that we could generate, we would always have dead batteries. So, from the beginning, we focused more on how much power we could consistently generate, and base our system off of that. To us, the meant using less, not necessarily making more. Our solar has kept up great so far, but our power needs have also been minimal. We have autopilot and a chart plotter that are always on when sailing. We also use our laptops constantly and run a small inverter for tools and small cooking appliances like blenders. We have all LED lights too. We don’t have a refrigerator yet or windlass. But they are on the short list. We also have yet to capture any power from the prop while sailing. So there is still room to capture more power if we need it. 

As we continue to sail further and upgrade and modify our system, we will also continue to update you on how it all works here. So keep a look out for updates on our Facebook page and in future videos.  


sailboat electric engine conversion

We may have a spinning Motor . . .

But the fun has just begun..

Well, our motor works. It pushes our boat reliably. The Electro-Beke experiment is a success, at least in our eyes. Now the real fun begins. We’ve proven to ourselves that we can sail further that we thought and use the motor less than we originally planned. So, what’s next?

“We have a few more project on the list of upgrades and modifications.”

We have a few more projects on the list of upgrades and modifications. The first thing on the list is to rewire our system and remove the redundant components left over from the direct drive phase. After that, installing some better gauges and monitoring systems would be really nice. There is a “fuel gauge ” we would like to install for the motor bank and house bank. It is simple and relatively smart. It will give us an accurate state of charge in a quick glance. 

Next on the list will be installing a charge controller or developing a similar system to allow us to capture power from the spinning prop while under sail. Technically our motor is capable of it, and early tests have augmented this theory. We are currently working with a few companies to figure out what the best system will be. 

We also need to install a larger heat sink for our motor controller. The one that came with it is designed for air movement across its fins and is therefore undersized for our needs. However, we may be upgrading to a true SEPEX motor controller before long, so it will handle regeneration and would require a different heat sink anyway. 

The big ticket item on the list is to install a large LiFePO4 battery bank. We have our eyes out for a salvaged Nissan Leaf or Chevy Volt that still has its battery bank intact. We’ve seen them for sale before and would love to get our hands on one. LiFePO4s are much more stable than other types of Lithium Ion batteries. But, we’ll talk about that if and when we actually get our hands on some. 

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Saildrive propulsion systems

The most powerful electric sail drive system from serial production.

Deep Blue 25 SD

Perfectly matched system integration rather than an assortment of components

The most powerful electric saildrives come from Torqeedo series production. The Deep Blue 25 SD propels sail yachts of up to 40 feet in length to speeds of up to almost ten knots (18 km/h), or smaller boats even faster when planing. This makes cruising with large sail yachts completely emission-free with virtually no noise or vibration. The Deep Blue 50 SD offers twice the performance. The Deep Blue sail drive is part of a completely integrated comprehensive system that was developed using industrial engineering methods, comprises high-tech components and which is manufactured in series production.

sailboat electric engine conversion

Deep Blue Saildrive for sailboats and catamarans

Light and quiet.

With an overall weight of about 125 kg for motor, sail drive and electronics, the Deep Blue 25 SD (50 SD ≈ 180 kg) weighs less than a conventional saildrive with combustion engine. This benefits weight distribution on board, as the low net weight of the Torqeedo Deep Blue Saildrive makes a sailboat noticeably lighter at the stern than a similar configuration with a petrol or diesel engine when the motor is installed toward the rear. The weight of the lithium battery can also be used to advantage in the design of the boat. The fact that the battery package can be arranged variably when the Torqeedo Deep Blue Saildrive is installed allows the weight of the drive system to be distributed around the centre of the vessel. This is the arrangement favoured by boat builders and boatyards.

Travelling silently even when under motor power

No sailor likes the sound of an engine when travelling in calm conditions or when casting off or landing under engine power. In contrast to conventional petrol- or diesel-powered sail drive engines, the Deep Blue 25 SD & 50 SD operate quietly, creating extremely low noise emissions. The electric sail drive operates almost in silence owing to the nature of the system. Due to the system, the electric saildrives operate almost silently.

Number 1 in power delivery

The Deep Blue Saildrive produces the equivalent of up to 80 hp of power, ideal for use in displacement boats and large sailing yachts.

Complete integration

The Saildrive drives are part ofTorqeedo’s Deep Blue series of high-performance motors. The high-tech components of the fully integrated overall system are carefully selected to match each other and are perfectly adapted for use on water. They offer professional safety features, compliance with international standards at system level and extreme ease of operation. The motors can also be used to generate electricity. The seamless integration of the saildrives into Torqeedo’s hybrid system offers the option of recovering energy while under sail through hydro power generation using the electric drive.

Low incidental costs

There are no incidental costs for petrol or diesel or for regular maintenance incurred by a combustion engine. Since the lithium batteries are manufactured to the same high standards of quality as in the automotive industry, Torqeedo offers a warranty of nine years on battery capacity, promising a residual capacity of 80 % after nine years of daily use.

Deep Blue Saildrive Benefits

All benefits at a glance

  • Most powerful electric saildrive from industrial production
  • Space-saving and boat construction-friendly design
  • Part of a balanced, fully integrated system
  • Compatible with all popular engine beds for saildrives


Home » Blog » Gear » Buyers guide to electric boat motors (2023)

Buyers guide to electric boat motors (2023)

By Author Fiona McGlynn

Posted on Last updated: August 3, 2023

Considering making the switch to an electric boat motor? With electric vehicles now commonplace on the roads, it’s no wonder so many boaters are curious about electric boats.

While electric boat motors have been around for a while, in the last several years the technology has taken huge leaps, resulting in more powerful motors, longer-lasting batteries, and ultimately more options for recreational boat owners.

Today, many types of boats can be outfitted with an electric propulsion system including pontoon boats, sailboats, jon boats, powerboats, fishing boats, yachts, and trawlers . If your boat’s combustion engine is in the range of 1 to 135 hp (.75 to 100 kW), you should be able to find an electric substitute.

While electric boating hasn’t gone mainstream—it’s estimated that close to 2% of recreational boats are electric—it’s still a great time to be thinking about making the switch, particularly if you own a tender, sailboat, or boat on a green lake where combustion engines are prohibited.

Table of contents

  • 1.1 Benefits
  • 1.2 Drawbacks
  • 2.1.1 Key features of electric outboard boat motors
  • 2.1.2 Electric outboard manufacturers
  • 2.2.1 DIY electric inboard boat motor conversion
  • 2.2.2 Key features of electric inboard boat motors
  • 2.2.3 Electric inboard manufacturers
  • 2.3.1 Serial vs. parallel hybrids
  • 2.3.2 Key features of marine hybrids
  • 2.3.3 Marine hybrid manufacturers
  • 2.4.1 Electric pod and sail drive manufacturers
  • 3 Batteries
  • 4 Ready to catch the electric boating wave?

electric inboard boat motor

Benefits and drawbacks of electric boat motors

Electric marine motors offer several advantages over internal combustion engines:

  • They’re completely silent .
  • No noxious fumes or smelly exhaust gases to deal with.
  • Instant torque.  Electric propulsion provides instant torque, giving you better maneuverability and more consistent speeds in choppy conditions.
  • Lightweight.  An electric setup (including motor, batteries, and generator) typically weighs less than its diesel counterpart.
  • No fuel cost.  Charging an electric boat may cost a couple of dollars per charge.
  • Easy to maintain.  Imagine the maintenance on an outboard with no gas, spark plugs, or oil! Electric motors are simple, more reliable, and virtually maintenance-free.
  • Renewable power.  Once you’ve gone electric you can get power from renewable sources like wind generators and solar panels.
  • Better for the planet.  Electric marine motors don’t produce water pollution or produce harmful emissions like carbon dioxide (CO2), nitrogen oxides (NOx), and hydrocarbon (HC).

electric boat motor range tracking

  • Range.  The greatest drawback of electric boats is their limited range, which is often measured in the 10s of miles. Range is limited because batteries don’t have the same energy density as fuel — they can’t provide the same energy, pound-for-pound as a tank of gas. A good battery monitoring system, one that displays the remaining range in real-time, can help boaters manage energy consumption and ease range anxiety. For those who want to go farther afield, hybrid propulsion may be a better option.
  • Upfront cost.  This new technology isn’t cheap. For example, a small electric outboard boat motor may sell for two-and-a-half times the cost of a gas outboard. However, prices are expected to come down as the industry reaches scale.

electric boat motor

Types of electric boat motors

Electric outboard boat motors.

Some of the first electric outboards to hit the recreational boating market were smaller electric motors, typically used as trolling motors on fishing boats.

Today,  it’s possible to buy far more powerful electric outboard motors in the 1 to 80 hp (.75 to 60 kW) range , with ever more powerful versions hitting the market each year. In 2022, Norwegian start-up, Evoy launched the world’s most powerful outboard to date, the 225kW Storm, a 300-hp beast of an electric outboard! 

The range on electric outboard boat motors varies dramatically depending on your boat, total weight, propellor, and battery capacity .

The range also depends on how fast you want to travel. If you go slowly you’ll have a much greater range.

For instance, at a slow speed (5 knots) Torqeedo’s Deep Blue 50R , a 50 kW motor (80 hp equivalent) with a 40 kWh battery, has a listed range of 33-100 nm. But at full throttle (20-25 knots), the listed range drops to 16-20 nm.

To get a better sense of what range to expect on your boat (at both low and high speeds), you can look at the manufacturer’s website. See our list of electric outboard brands below.

solar panels

One of the great things about electric outboards is that they can use renewable power sources. So, for instance, you could plug your boat into a portable solar panel while picnicking and get an extra boost for the trip home.

Some electric outboard boat motors can even generate power! Motors with hydro regeneration capabilities can charge the batteries while the boat is being towed or under sail.

While hydro regeneration is a fairly new feature for electric outboards, some manufacturers, like EPropulsion, are offering it across their outboard product line.

electric outboard boat motor

Key features of electric outboard boat motors

Each electric outboard motor brand has slightly different standard offerings and add-on features. Here are some of the key features and options to look for.

  • Waterproof.  Some electric outboards are fully sealed and designed to withstand immersion
  • Remote controls. Choose between tiller and remote throttle controls
  • On-board computers . Some electric outboards come with chartplotter connectivity, navigation functions, sonar, GPS anchoring, and autopilot features
  • Built-in or stand-alone batteries.  Some of the smaller motors come with built-in batteries, while the larger ones have separate battery packs
  • Battery monitoring and tracking systems  that calculate and display the remaining range in real-time
  • Shaft length.  Electric outboards come in both short and long shaft lengths to accommodate a variety of applications.
  • Hydro regeneration capabilities 

electric outboard boat motor

Electric outboard manufacturers

These electric outboard boat motor manufacturers (listed in alphabetical order) range from small startups to large companies and serve the North American market.

If you’re looking to learn more about what each of these companies offers (and how they compare) I’d highly recommend checking out the  Plugboats’ electric outboard guides and directories . Jeff Butler, the editor at Plugboats has done a great job of compiling motor specifications from across the market.

Headquartered in San Diego, California,  Bixby  makes a small electric motor system for kayaks, inflatable boats, canoes, and paddleboards.

Elco  has been building electric motors for 125 years and counts the likes of Henry Ford and Thomas Edison among their customers. Their award-winning electric marine motors range from 5 to 50 hp. The company is based in Lake George, New York, and its electric motors can be found on boats around the world.

Flux Marine

Flux Marine was founded by mechanical engineering Princeton grads and offers three outboard models—a 40 hp, 70 hp, and 100 hp. In 2021, they won an award for the best new green product at the Newport International Boat Show.

Joe Grez, a consumer product developer from Washington, invented the  EP Carry , a compact, ultralight electric outboard system because he was concerned about exposing his young daughter to the carbon monoxide (CO) emissions produced by gas outboards.

The EP Carry retails for $1,600 and is a great size for small vessels like dinghies, canoes, inflatable boats, and kayaks.


ePropulsion , based in Guangdong, China, manufactures 3 to 9.9-hp electric motors for sailboats, fishing boats, as well as dinghies and tenders. They all come with hydro regeneration capabilities.

Mercury Marine launched the Avator 7.5 electric outboard (3.5 hp equivalent) in early 2023. The leading outboard manufacturer is currently developing more powerful 20e and 35e models which it plans to release later this year.

In 2023, Newport , a well-known US-based inflatable boat manufacturer, launched three small outboards ranging from 1.8 to 3 hp.

If you’re into fishing, you’re probably familiar with the Minn Kota  name, derived from MINNesota North DaKOTA, prime fishing country where the company has its roots. They introduced their first electric trolling motor back in 1934 and they’ve been making them ever since.

Pure Watercraft

Pure Watercraft  was founded by CEO Andy Rebele in Seattle in 2011. Their 25 kW (50 hp) motor starts at $16,500.

Ray Electric Outboards

Ray Electric Outboards is a 3rd generation family-owned business based in Cape Coral, Fl. They manufacture one outboard model that can be operated at different power ratings ranging from 10 to 22 hp.

Stealth Electric Outboards

The 50 and 75-hp  Stealth electric outboards  were developed by Scott Masterston of Houston, Texas.

German manufacturer,  Torqeedo , has been leading the propulsion industry for years and sells some of the best e outboard motors in the 1 to 80-hp range

Vision Marine Technologies  (formerly The Canadian Electric Boat Company). 

Based in Quebec, Canada,  Vision Marine Technologies  has been in the boating industry for 25 years and produced some very innovative electric boats. In 2021, they launched E-Motion 180E, one of the most powerful electric outboards on the market.

electric inboard boat motor

Electric inboard boat motors

Today’s electric inboard motors can provide anywhere from  3- to a whopping 330 hp (2 to 246 kW)  and are used in a range of applications from heavy displacement vessels to fast, planing powerboats.

Similar to outboards, the range on electric inboard engines will vary based on your boat, load, battery capacity, and boat speed (among other things).

However, with an inboard electric boat motor, you have the option of a hybrid motor which can significantly extend your range. We’ll discuss the pros and cons of hybrid boat motors later in this post.

Sailors may also want to consider choosing an inboard electric motor with hydro regeneration capabilities. These electric power motors can charge the battery while the boat is under sail.

Electric motor for sailboat

DIY electric inboard boat motor conversion

One way to save money on an electric inboard is to do the installation yourself. There are a few DIY electric inboard boat motor conversion kits available on the market.

I’ve spoken with a few sailors who’ve had great success replacing their inboard diesel engines with these electric boat motor conversion kits from  Thunderstruck-EV , an electric drive manufacturer in Santa Rosa, California.

Key features of electric inboard boat motors

Each brand has a slightly different set of electric inboard motor options. Here are some of the key features and options to look for.

  • DIY conversion kits
  • On-board computers  and touchscreen display
  • Waterproof  system components

Electric inboard manufacturers

US manufacturer, Elco Motor Yachts , has been building electric motors for over 125 years, having gotten their start in 1893, supplying electric boats for the Chicago World’s Fair. They have seven inboards ranging from 6 to 200 hp.

Electric Yacht

Electric Yacht  is a US supplier focused on providing plug-and-play electric motors for DIY installations on sailboats. Their electric propulsion systems range from 10 to 30. They’ve had over 450 installs in 10 years of production.

Oceanvolt  is a leader in regenerative systems and their electric inboard motors are popular among sailors. They offer shaft drive systems ranging from 6 to 60 hp.

Torqeedo, a German manufacturer, is the world’s leader in electric boat motors. They have two lines of inboards, one for displacement boats and another for fast planing boats. Their Deep Blue inboard systems range from 25 kW to 100 kW (40 to 135 hp)

Hybrid systems

Hybrid systems combine an electric motor and combustion engine, so you can cruise in silence (but know you’ve got enough gas to get home). These systems offer  many of the benefits of pure electric motors, without the limited range. 

If you want  additional power for onboard luxuries  like air-conditioning, hybrids can also provide a significant increase in house-side fuel efficiency.

The downside to any hybrid solution is that the systems are far more complex . Not only do they require more equipment, but, for an optimized system, you’ll need highly sophisticated software to manage multiple power sources and switch back and forth between diesel and electric.

Unsurprisingly, the increased complexity adds cost, making hybrids less economical than either a conventional or pure electric install.

Serial vs. parallel hybrids

As with cars, there are  two types of hybrid systems: serial and parallel.  A serial hybrid uses a generator to power a large electric motor connected to the drive shaft. Whereas, a parallel hybrid has both a conventional combustion engine and a small electric motor connected to the drive shaft.

There are plenty of factors to consider when choosing between a parallel and serial system. Marine mechanics and electrical expert, Nigel Calder, does a great job of explaining  serial and parallel hybrids  in detail.

In general, serial systems may be a better fit for boats that can get most of their propulsion energy from renewable sources (e.g., a sailing catamaran). Whereas, a parallel system makes more sense on boats that regularly require sustained propulsion (e.g.,  Greenline’s power yachts ).

hybrid electric marine propulsion engine

Key features of marine hybrids

  • Parallel and serial hybrid options
  • Integrated energy management  systems

Marine hybrid manufacturers

Elco motor yachts.

Elco  manufactures serial, parallel, as well as a combined serial-parallel system. Their systems can be used on sailboats, trawlers, yachts, and boats up to 85′ feet.

Hybrid Marine Ltd.

Hybrid Marine  sells parallel hybrid systems in the 10 to 230 hp range. Beta, John Deere, and Yanmar’s hybrids all incorporate Hybrid Marine technology.

Finnish manufacturer,  Oceanvolt , offers serial hybrid systems for both sailboats and powerboats.

Torqeedo  makes hybrid systems for yachts up to 120 feet as well as powerful motorboats.

Electric pod drive and sail drive

Several manufacturers are now making electric pod and sail drives. These electric drive systems are more efficient and can save space onboard.

electric pod drive

Electric pod and sail drive manufacturers

Electric Yacht  produces a range of sail drives that can replace diesel engines up to 75 hp.

propulsion  sells a 3 hp, 6 hp, and 9.9 hp fixed pod drive.

Oceanvolt’s  sail drives range from 6 kW to 15 kW (8 to 20 hp)

Torqeedo  sells a 40 hp and 80 hp equivalent electric sail drive as well as electric pod drives in the 6 to 25 hp range.

While it’s possible to power an electric motor with a conventional lead-acid battery, there are many  good reasons to upgrade to lithium-ion batteries.

Their increased usable  capacity is roughly double  what you can get out similarly sized lead-acid battery. More battery capacity means more range—and hours of fun—on your electric boat.

They also  charge more quickly  and have a  longer life span  than lead-acid batteries. Unlike flooded lead-acid batteries, which need to be watered, lithium-ion batteries are practically maintenance-free.

electric boat motor batteries

The downside is that lithium-ion batteries are far  more temperature-sensitive  and can’t be charged much above 113 F (45 C) or below 32 F (0 C).

They  can also present major safety issues . Lithium-ion batteries can go into what’s known as thermal runaway—a self-heating process that can cause the battery to catch fire.

Simply put,  lithium-ion batteries are NOT a drop-in substitute for lead-acid batteries.  They need to be specially designed for the marine environment and paired with a robust battery management system.

Electric motor manufacturers often provide complete solutions (including motor, batteries, and battery management system). It’s a good idea to work with a manufacturer with extensive marine experience and an ABYC-certified technician on any installation.

The other catch is that lithium-ion batteries  cost two to four times   as much as lead-acid  batteries. However, the increased capacity and longer life span may make lithium batteries a better value option over the long run.

Ready to catch the electric boating wave?

With ever more powerful and feature-packed electric options launching each year, it’s an exciting time to be in the market for a new motor or engine. If you have any doubts about whether an electric boat motor is right for you, head to your local boat show and see, first hand, what all the buzz is about.

Fiona McGlynn

Fiona McGlynn is an award-winning boating writer who created Waterborne as a place to learn about living aboard and traveling the world by sailboat. She has written for boating magazines including BoatUS, SAIL, Cruising World, and Good Old Boat. She’s also a contributing editor at Good Old Boat and BoatUS Magazine. In 2017, Fiona and her husband completed a 3-year, 13,000-mile voyage from Vancouver to Mexico to Australia on their 35-foot sailboat.

Douglas McQuilken

Sunday 30th of January 2022

Great article!

For those who wish to collaborate with prospective & current electric boaters, highly recommend this forum - https://groups.io/g/electricboats

Thanks for the suggestion, Douglas!

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OCEANVOLT sail drive motors

Oceanvolt offers a range of sail drive motors to provide propulsion and hydro generation for vessels ranging from 15 to 80 feet.

Sail Drive (SD)

SD Sail Drive Systems

  • Synchronous permanent magnet electric motor.
  • Sail Drive with 1.93:1 reduction.
  • Lightweight: weighs as little as 42.5kg (motor & sail drive).
  • The only complete electric inboard propulsion system with
  • EMC certified closed circulation liquid cooling providing both cooling and lubrication.
  • Functions as a hydro generator to generate power while under sail.

system installation layout (example)

  • Nominal Power
  • Reduction Ratio
  • Motor weight

Oceanvolt servoprop


The patented Oceanvolt ServoProp variable pitch sail drive combines a high efficiency sail drive with the most powerful hydro generator on the market. The unique feature of the ServoProp is the possibility to turn the propeller blades more than 180 degrees. The software controlled variable pitch sail drive adjusts the pitch of the propeller blades automatically so that the power generation and power output are optimal. Combined with uniquely designed blades it delivers optimal efficiency in both forward, reverse and hydro generation. And with the blades set to the neutral sailing position, the propeller creates extremely low drag similar to the drag of a feathering propeller. The benefits of ServoProp include an estimated +30% increase in forward propulsion, +100% in reverse and +300% increase in hydro generation effect. 

A normal fixed propeller (that by nature does not have the blades ideally shaped for regeneration) generates less than half the power of ServoProp at a given boat speed. ServoProp is capable of generating more than 1 kW at 6-8 knots. The power generated can be used to power both the propulsion system as well as all the electronics on board without the need to have a separate generator. With this in mind we can definitely start talking about the possibility of a totally self-sufficient cruiser!

The ServoProp is suitable as a propulsion motor for monohulls up to 50 ft & multihulls up to 60 ft. It can also be used as a hydro generator in boats up to 100 ft.

sailboat electric engine conversion

Convert your Vessel to Hybrid or All-Electric

We offer a complete service beginning with system design to Convert to Electric. Thereafter our engineering staff can remove you old engines and power systems where necessary.

We have a complete engineering service and can take your yacht from beginning right through to commissioning and sea trials.

Option 1 – a hybrid system that includes a highly efficient generator instead of a complete Convert to Electric.

Option 2 – Convert to Electric with an all-electric and solar solution, which means no more exhaust fumes aboard sailboat ever again.

convert your yacht to electric


sailboat electric engine conversion

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sailboat electric engine conversion

Electric Motor conversion

  • Thread starter MPAPC4
  • Start date Sep 1, 2012
  • Catalina Owner Forums
  • Catalina 30

Hi all, it has been about 4 months since I converted my Catalina's Atomic Bomb to Electric propulsion. The ingredients were, 9hp AC brush less motor, Charger, 4 AGM Batteries, Throttle, and a computer control/display and of course various cables etc. Although its too soon to know in the long run whether a good or bad investment (reliability) I do want to say that the performance of this installation has been outstanding. What I like is the instant on power, motor sailing against the tides, no refueling, simplicity of the operation and being able to customize the throttle settings. What my wife likes, No noise, no exhaust, no fumes, no oily bilges. Everyone always wants to know the range, it depends on the throttle setting and the type of prop installed. I am working the numbers and hope to post them soon but I get a top speed of 6 knts at full throttle and based on how I use the boat mainly coastal and bay sailing. I have to work hard to get the battery charge below 50%, mainly because I use the motor to get out of the marina and sail everywhere else but have motor sailed out of South San Diego Bay which is roughly 7 miles against the tide. While sailing the prop starts to trail and at 4.25 knts the motor acts like a generator and recharges the batteries. I bought a Honda 2000 generator for AC power and once charged the batteries from a 64% charge to 100% (2 hours) at a overnight anchorage. Anyhow, if anyone has any questions on the performance or the installation please ask, I am interested in other electric conversions.  


is there a single location to get all the parts maybe in a kit or did you put it all together yourself with may be a golf cart motor  

Any idea on what this type of installation has cost? Would this be a viable alternative to replacing an engine? How does the weight compare to a diesel or gas engine?  


MPAPC- What size batteries did you use? Also did you change the prop from the original? I know your pleasure as my C27 is an electric conversion and if my C30 diesel ever dies I'll do it to that boat too.  

Foolproof The cost does depends on whether you buy a complete system from a vendor and have it installed or buy the parts and do the installation yourself. I spent about $2600.00 on my C27 conversion, assembled and installed myself. Weight depends on the battery bank size. My conversion weighed a little less than the A4 and full gas tank it replaced. Doug  



I've toyed with the idea of converting my C27 to electric, and after spending another weekend replacing the exhaust manifold, I'm getting really tired of jacking with engine stuff when I want to sail. Don't get me wrong, the M18 is an awesome little engine, but it is 28 years old and I think of how much room I would gain by ditching the fuel tank, exhaust and such, and I am landlocked, not oceanside.  


MPAPC4 said: Hi all, it has been about 4 months since I converted my Catalina's Atomic Bomb to Electric propulsion. The ingredients were, 9hp AC brush less motor, Charger, 4 AGM Batteries, Throttle, and a computer control/display and of course various cables etc. Although its too soon to know in the long run whether a good or bad investment (reliability) I do want to say that the performance of this installation has been outstanding. What I like is the instant on power, motor sailing against the tides, no refueling, simplicity of the operation and being able to customize the throttle settings. What my wife likes, No noise, no exhaust, no fumes, no oily bilges. Everyone always wants to know the range, it depends on the throttle setting and the type of prop installed. I am working the numbers and hope to post them soon but I get a top speed of 6 knts at full throttle and based on how I use the boat mainly coastal and bay sailing. I have to work hard to get the battery charge below 50%, mainly because I use the motor to get out of the marina and sail everywhere else but have motor sailed out of South San Diego Bay which is roughly 7 miles against the tide. While sailing the prop starts to trail and at 4.25 knts the motor acts like a generator and recharges the batteries. I bought a Honda 2000 generator for AC power and once charged the batteries from a 64% charge to 100% (2 hours) at a overnight anchorage. Anyhow, if anyone has any questions on the performance or the installation please ask, I am interested in other electric conversions. Click to expand

I went to Electric Yachts online, it was a kit sans the batteries and battery cables. There are various choices of batteries out there, I went with the 4 AGM 12volt 200 AH (8a4d) Delco. they are heavy, i placed two where the fuel tank was and two by the motor. The motor is only 50 lbs and the atomic was about 340 lbs, ea battery is over 125 lbs so it nearly replaced the weight that was in the boat, good news is that I carried the weight fwd by a few inches which is closer to the mast. the entire installation not including the preparation was 2.5 days, the motor mount that comes with the kit fits right in the exact same spot as the atomic foundation pads sat, alignment to the shaft was easy. I did change the prop, went to a 13x12 two blade bronze which drags more but that was the point. I just finished the beer can season and placed 8th, I would have placed higher but I have inconsistent crew so the bigger prop doesnt slow me down.  

Forgot, the AGM batteries are maintenance free, and can be installed at angles, the standard wet lead acid batteries are the cheapest but you have to keep the water level up. The other choice was Lith or Nicad, all out of my price range. The Motor kit which included the Motor, Controls, computer and cables cost me $4k, AGM batteries were $425 ea, the charger which is a programmable charger was about $380, battery cables which were built on the spot were $150. As far as cost, I think I went medium, there are options and could have saved another $800 dollars.  

Shipwreck66 I was a diesel mechanic in the Navy (24 yrs), I also had my outboard certification for both Merc's Evenrude/Johnsons. I just got tired of spending a lot of time working on the engines, fuel systems fuel tanks so when the Atomic 4 blew a head gasket and the sump filled with salt water I was going to replace the engine with a zero hour engine from Moyer Marine until I found the ad for the electric power conversion from Electric Yachts, based on my use of the boat it made perfect sense. If and when I get a blue water boat, I may do the same. The Universal diesels are simple so keep what you have until it gives up the ghost and then decide.  


MPAPC4: Thanks for the info. I think all of us would like one day switch to something that is simpler, less maintenance & cleaner. I too would like to do this one day. Hopefully the battery technology will get a lil cheaper by the time my lil diesel decides to die. Mine is 32 years old & already on its 2nd rebuild. Unitl now I figured there wasn't a battery bank out there that would power an electric engine capable of moving a haus of a boat like ours. Can you post some pics? Ps. Do you still keep a seperate house battery bank for your electric needs while on the hook overnight? Cheers.  

jrowan said: MPAPC4: Thanks for the info. I think all of us would like one day switch to something that is simpler, less maintenance & cleaner. I too would like to do this one day. Hopefully the battery technology will get a lil cheaper by the time my lil diesel decides to die. Mine is 32 years old & already on its 2nd rebuild. Unitl now I figured there wasn't a battery bank out there that would power an electric engine capable of moving a haus of a boat like ours. Can you post some pics? Ps. Do you still keep a seperate house battery bank for your electric needs while on the hook overnight? Cheers. Click to expand

Heading out of marina today, first time since replacing exhaust system, and engine died while heading out. Drifted into a vacant slip and spent the 101degree afternoon SERIOUSLY pondering the electric idea again. Actually, the culprit was a air bubble that got in last week while replacing exhaust, don't ask me how. Took me awhile to find the air blockage, wasn't in the usual places. All is well now and everything runs dandy. But oh how all electric sounds so good.  

There is a blog for a electric conversion of a Nonsuch 30 who sails the LI sound. Interesting reading. http://biankablog.blogspot.com/  

I feel for ya shipwreck. My old Yanmar diesel on my last boat - an S 2 used to get air in the lines before I took out the buggering mesh stuffed into the fuel pickup tube in the tank. It would run great for about 10-15 minutes & then die in the entrance out of our channel. I was alsways lucky that there was a fellow sailing buddy to give me a push back in, but it could've been nasty otherwise. Funny how the engine never wants to die BEFORE you leave the dock! lol.  

yeah, that's the damnest part. I had it idling in the slip for about 10 minutes while checking the new exhaust for leaks, no problem. Back out, start forward two minutes later BLaaaaappp.  

whatfiero said: is there a single location to get all the parts maybe in a kit or did you put it all together yourself with may be a golf cart motor Click to expand
foolproof said: Any idea on what this type of installation has cost? Would this be a viable alternative to replacing an engine? How does the weight compare to a diesel or gas engine? Click to expand

Ok, new at this, I have 5 photos on my Photo album, can anyone access them or do I have to post them here?  



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Yamaha's Got a New 7600-RPM, 200-HP Four-Cylinder Engine

We'll take our new engine debuts where we can get them these days. Even if they're in boats.

yamaha four cylinder engine

But the marine industry is a different story, and in recent years some of the coolest new engines— Mercury's V-12 , Honda's V-8 —were designed for boats. Which is also the case for Yamaha's new 1.9-liter four-cylinder, which makes 200 hp at 7600 rpm and can be found powering high-output WaveRunners and jet-drive boats. It's not designed for cars, but the Lemons racers among us can dare to dream.

The 1.9-liter four replaces Yamaha's 180-hp 1.8-liter mill and blurs the performance line between the company's naturally aspirated and supercharged engines. Yamaha's supercharged 1.8-liter makes 255 horsepower, but in a WaveRunner there's not a huge practical difference between the boosted 1.8 in a SVHO model and the naturally aspirated 1.9 that powers HOs. Personal-watercraft manufacturers adhere to an agreement that's something like the old German pact to limit top speeds to 155 mph, except on the water the target is 65 mph. That spec includes a 2-mph fudge factor, which naturally means that PWCs of sufficient horsepower top out at an electronically limited 67 mph. Since a 200-hp WaveRunner can hit that limit, the only difference is how quick you get there.

a man riding a waverunner

The 1.9-liter, as a new design, enjoys a bundle of changes aimed at durability and refinement. One example: There's an extra bolt connecting the cam chain housing to the block—a little tweak that makes a big difference. "The cam chain room is a thin aluminum casting," says Mark Sagers, senior watercraft factory service technical specialist (in other words, the guy who knows all the engines inside out). "That great big straight piece of aluminum is like a sound board, amplifying the noise of the cam chain. But if you run a fastener from that to the main casting, it knocks that noise way down. That's important when you're sitting right on top of the engine and it's bolted to a guitar body, basically."

Performance-enhancing upgrades include a new exhaust manifold with dedicated pipes for cylinders one and four, a bore increase from 86 mm to 88 mm, and a channel to route cooling water between the exhaust valves to cool the valve seats. The 1.9 even uses about a half-quart less oil than the 1.8, because Yamaha determined that it could cut windage losses (read: increase horsepower) without sacrificing durability. And durability versus performance is always a tradeoff, whether on land or not. "In a 250-cc motocross bike, the maintenance schedule calls for a new piston every nine hours and it's putting out specific power like a NASCAR engine, or almost Indy," says Sagers. "Boats are more on the lower end of high performance, so we can make them last thousands of hours."

a person riding a waverunner

A car engine might well make its horsepower peak beyond 7000 rpm, but it isn't expected to spend much time there. An engine destined for a WaveRunner is a different story. "A lot of the durability testing is done fully loaded at wide open throttle," Sagers says. "These will run a very long time at WOT. Waverunners are often idling or WOT, and there's no middle ground. But I've seen Waverunner engines with more than 1500 hours and no major mechanical work. It's staggering that these mechanical things can live through this."

Still, 200 hp isn't enough for everyone. Logically, it would seem inevitable that this engine will get a supercharger and the 1.8-liter will be retired. Boost prognosticators might find a clue at the 1.9-liter's Coast Guard–mandated intake flame arrester—the intake manifold is cast around it so it can't be sucked into the engine. Which is the kind of thing that would probably only happen if said intake was huffing some major boost. Perhaps soon, it will be.

the engine in a waverunner

In the meantime, you can break the 200-hp barrier without forced induction. And for twin-engine boats, that means Yamaha is packing 400 horsepower into some of its 22-footers, which we imagine would mean 50-plus-mph top speeds given that the 210 FSH hit 48.0 mph with the 1.8s and their 360 total horsepower.

the twin engines in a yamaha 220 fsh boat

Yamaha has built some nice automotive engines—most famously, the Ford Taurus SHO's —but those of us dreaming of 200-hp Yamaha-powered Miatas will probably have to wait a while for these latest ones to hit the salvage yards. (You can spend that interim figuring out how to adapt a closed-loop cooling system, since the jet drive on these engines doubles as a water pump.)

Calling a powerplant a "boat motor" is traditionally a pejorative, meaning a low-revving hunk of iron, an outdated castoff better suited as a mooring. But motors are electric, and that's where things are heading on the highways. So if you appreciate the mechanical complexity and cleverness of engines, boats are the new—and maybe last—frontier.

Headshot of Ezra Dyer

Ezra Dyer is a Car and Driver senior editor and columnist. He's now based in North Carolina but still remembers how to turn right. He owns a 2009 GEM e4 and once drove 206 mph. Those facts are mutually exclusive.

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