Electric Boatlife: Reflections After a Year of Sailing with an Electric Motor

Sailing is one of the oldest forms of water transport and has lost none of its fascination. For many, sailing is a leisure activity and a way of life. The freedom of exploring the vastness of the sea, the wind's power, and the moment's tranquillity, punctuated only by the sound of the waves, is priceless.

But what happens when you add an electric motor to a traditional sailing yacht?

Innovation is rapidly reshaping boatbuilding and sailing, but what about electric mobility on water? Electric motors are hardly new these days; however, their prominence has often been eclipsed by internal combustion engines in personal mobility. Electric vehicles like cars, buses, bicycles, and scooters are now commonplace in the streets and cities. On the water, however, the landscape is different. While electrically propelled dinghies with small outboard motors have become popular, sailing yachts with electric motors as the primary drive remain a rare sight.

Picture a sailing yacht with an electric motor...

In discussions on forums, video platforms, or among seasoned sailors, the question often arises: Can you propel a sailing yacht with an electric motor? The answer is a resounding yes! But how does it function?

A sailing yacht powered by an electric motor operates much like an electric car. Instead of an internal combustion engine, it boasts a fully electric motor fueled by batteries. These batteries can be replenished by plugging into a wall socket, akin to electric cars, or, more intriguingly, by harnessing alternative energy sources such as solar panels, wind turbines, or hydroelectric generators. Sailing yachts offer ample space for integrating these sustainable power sources. Instead of a conventional fuel gauge, a display presents battery levels and energy consumption, ensuring you're always aware of your "fuel" reserves.

Now, let's delve into the technical details: What's the range, and how fast can you go?

Engine speed and range hinge highly on external variables. Considerations include the motor's power, the vessel's mass, currents, headwinds, and wave conditions.

Batterybank for the E-Motor

Disclaimer: Our experiences are necessarily one-sided, shaped by our unique boat and electric motor setup. For our sizeable Ferdinand, we admittedly have an underpowered configuration. Fortunately, the marine market now offers substantially more potent electric motors. Our journey into electrical engineering started from scratch when we acquired the boat, guided mainly by hands-on experience, old-school texts, and some trusty internet searches and friends. If there are any technical inaccuracies, please feel free to share your insights in the comments or shoot us a message on Instagram or via e-mail.

Here's our current setup for running our electric motor:

- 16.3 kW electric motor (48V)

- 15 kWh lithium battery bank

- 740W solar panels (48V)

Diesel Engine vs. Electric Motor: Parallels and Distinctions

Let's draw a simple comparison to illuminate the commonalities and divergences. Firstly, an electric motor also has a gear and propels the yacht forward or backward, making them more similar than one might think. As with a diesel engine, there is a relationship between RPM, fuel consumption, and speed. The only difference is that they have different names, and values and tick a little differently: Fuel consumption equals battery consumption, motor speed equals kilowatts, ...

Motor-Panel

We usually base our driving on kilowatts rather than speed because kW gives a better indication of actual consumption. Just as the diesel engine consumes significantly more fuel at a given speed of the motor, the battery consumption is exponentially related to the kilowatts used. We've found our optimal consumption/speed/range balance in the 1-2 kW range. Depending on conditions, we can maintain speeds of 1-3 knots. We might not break speed records, but with our 15 kWh capacity, we could theoretically cover 20 nautical miles (15 kWh divided by 1.5 kW, i.e., 10 hours at 2 knots). We could extend our range using a generator, creating a DIY hybrid. Nonetheless, we're can be more generous with the throttle during brief harbor maneuvers.

In practice, range isn't a concern as long as the wind cooperates. When it does, sailing is markedly faster, and the engine primarily aids in mooring and unmooring. In our 365 days aboard, we've unpacked the generator only twice – The first time was on our very first trip when we had no idea how everything worked, so it was only half the story 😉. There are, after all, quite a few parameters to keep in mind that are different than operating a regular engine. Anyway, we learned a lot in a short time on that first chaotic departure.

We see our primary role not as sailors but as travelers. Days spent anchored vastly outnumber our sailing days. So, what can an electric motor offer at anchor that a diesel engine cannot?

Full Battery Load at Anchorage

Sailors who've grappled with aging batteries and no solar power on a chartered vessel understand the challenge: You need the engine running to recharge service batteries. Conversely, with an electric motor, we usually boast abundant power at anchor, enabling us to use our engine batteries to recharge service batteries, highlighting the first advantage of an electric motor.

Of course, like any propulsion system, there are pros and cons, which we'll briefly outline.

- Let's begin with the drawbacks:

Range & Power

Electric motors impose limits on range and power. This constraint stems from battery capacity limitations and exponential energy consumption as power increases. Furthermore, electric motors without cooling systems may overheat at high power levels, a consideration seldom encountered with diesel engines, which routinely feature cooling systems. Consequently, we've become accustomed to "sailing to the bitter end.", as we say in Austria. Extended periods of 4 knots or higher are usually unattainable with the motor, motivating us to rely primarily on sail power. Instead of the convenience of firing up the engine to tackle the last few miles against the wind or hasten our arrival, patience becomes our ally. After all, we're aboard a sailboat, not a motorboat.

Wind Dependency

One significant disadvantage of an electric yacht is its heightened dependence on weather and wind conditions, which requires better route planning and more time. Arriving at a specific location at a particular time may prove challenging or need additional time due to wind vagaries. The option to merely start the engine and drop the sails when the wind falters is only available if the sea is exceptionally calm, daytime and sunlight are abundant, or you have a generator. While solar, wind, or generator power continues to recharge the batteries during sailing, it's typically wise to depart with a favorable wind forecast. When planning our voyages, we need to consider the influence of tides and currents more, aiming to leverage them to our advantage rather than battle against them.

Harbor maneuvers

Harbor maneuvers, especially when substantial engine time precedes entry or when confronted with strong currents and winds, necessitate even more meticulous planning. At one Tenerife harbor, we changed berths five times due to various complications, all in a limited and windy space. The absence of auditory cues The absence of auditory cues regarding the motor operation is an added challenge. One often relies on sound to gauge throttle when operating diesel engines. Instead of listening to the motor, we must rely on displays and visual judgment only, which can be tricky when navigating tight spots.

Charging Time

While we've yet to thoroughly explore this drawback, as we tend to cruise sun-soaked locations, a depleted battery requires waiting until the solar panels fill up the battery or a harbor stop for shore power charging, akin to recharging an electric car. This inevitably takes longer than a quick diesel fill-up at a gas station and may entail an overnight marina fee.

- Now, let's explore the advantages of an electric yacht:

Maintenance Costs and Time

Compared to boats with internal combustion engines, electric motors are virtually maintenance-free. Their simplicity, featuring few moving parts, minimizes wear and tear. No oil or filter changes, no fretting over contaminated fuel or diesel-related issues, and no engine compartment mess. Over the course of a year, our electric motor has demanded zero maintenance costs and zero hours of our time—a remarkable benefit.

Moreover, the setup's flexibility is a significant advantage. Should you desire greater range, simply augment battery capacity. Need quicker battery recharging? Install additional solar panels.

Silence

Numerous sailors relish that special moment after departing from a harbor or anchorage, where the motor has been their companion, and then, as they hoist their sails, the engine finally yields to the embrace of silence. This transition usually marks the beginning of serene sailing. You'll experience this moment never or constantly with an electric motor, depending on your perspective. Even while the engine runs, you can relish the sounds of the sea, uninterrupted by a loud engine hum — pure "silent sailing". This is not only just relaxing during the day, but also your sleeping crew members won't wake up from starting the motor at night.

Last but not least: As we silently navigate through a slender harbor, we inevitably attract curious gazes. And when we dock at the "fuel station" (where we replenish our water tanks), it often leads to conversations similar to this:

Us: "Could you please release the lines!"

Attendant at the petrol station: "What? Are you certain? The engine hasn't even roared to life yet?"

Us: "Actually, it's been running for a while. We're powered by an electric motor!"

Eco-Friendly and Sustainable Travel

The sustainability factor, alongside the allure of experimentation, ultimately persuaded us to adopt this technology. In a year of ownership, we've consumed only about 5 liters of petrol (for the generator) to power our "Ferdinand".

Our primary source of propulsion is almost entirely solar-based, utilizing the sun to charge our engine batteries. The power of nature characterizes our journey— be it the wind in our sails or the sun on our solar panels — while producing minimal emissions. Moreover, charging service batteries from engine batteries, typically almost at 100% capacity while at anchor, eliminates the need to run the engine unnecessarily or inhale exhaust fumes from your vessel.

Range & Performance

Here's where we want to transform a disadvantage into an advantage. As discussed earlier, the electric motor's limited range and power frequently lead to more extended and demanding voyages. While this presents challenges, we readily embrace them. After all, we chose a sailboat because sailing is our preferred mode of travel, for better or worse. We keep our sails unfurled in situations where we might otherwise start the engine. Thus, we've honed our sailing skills, mastering the art of optimizing sail trim and sailing more efficiently.

During extended ocean voyages, the capacity of batteries to replenish themselves during sailing becomes an indispensable asset. This self-sustenance isn't achieved through regeneration, a process typically demanding speeds we rarely attain. Instead, it relies on harnessing the inexhaustible power of the sun. Our solar panels dutifully replenish our batteries even as we cruise along. The effectiveness of this operation hinges on variables such as weather conditions, the time of day, and our chosen course, ranging from optimal performance to a more moderate outcome. In this scenario, the skies above become our equivalent of diesel fuel reserves, especially when navigating regions blessed with abundant sunlight.

- Conclusion

In summary, having an electric motor on a sailing yacht presents a multitude of advantages and disadvantages. Of course, there are times when we wish we had a diesel engine, but when we hear about other sailors and their numerous engine problems and maintenance, we are very happy with our electric engine. We would argue that many diesel owners would want an electric engine in many situations if they knew the benefits! It is important to think carefully about your needs and how you want to use your yacht before buying or converting. While there are instances when a diesel engine might be preferable, our experiences have left us content with our electric engine.

Suppose you desire the freedom and serenity of sailing while upholding environmental consciousness. In that case, an electric motor becomes a compelling choice—especially in regions blessed with abundant sun and wind, and if you have some extra time to spare. Sailing, inherently "slow travel", gains an added serenity dimension through an electric motor — a subtle deceleration.

We hold optimistic expectations that the forthcoming years will witness a surge in electric mobility on water, steering electric propulsion from its current rarity towards becoming a standard practice, mirroring the transformative journey we observe in the realm of electric cars and scooters.