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Electric vs combustion engines – are electric boat engines worth it?

We briefly overview the similarities and differences between electric boat motors and combustion engines. What are the advantages of the electric motor on the boat?

Can I drive just as fast with an electric motor as with my combustion engine, or am I slower? Do not worry! An electric motor is just as excellent for propelling your boat. So, at maximum speed, the two motor types are on par.

What does the speed of the boat depend on?

We initially thought that only the engine was decisive for the speed. However, the rate is more dependent on your boat than the engine. In our article Everything about your boat, we tell you more about the economic speed and which values are necessary to calculate the rate.

Energy consumption of the electric motor and combustion engine on the boat?

This connection is also constant! Important: The faster you drive, the more energy you use. Whether with electricity, petrol or diesel. And exponentially to the third power! What does that mean? If you want to double the speed, you need eight(!) times as much energy as before.

We, therefore, recommend travelling at a gentler speed, regardless of the motor. Of course, you can also turn it up a notch! However, you should always have enough battery capacity or extra fuel to stay supplied!

So it is not the energy consumption that is decisive, but rather the type of storage on board, and here there are differences.

The functionality of electric motors and combustion engine

Technically, electric motors and combustion engines are, of course, fundamentally different.  This is more about the purpose pursued by both machines.

The propeller converts the engine’s power into thrust and pushes the boat in the desired direction. Combustion engines and electric motors have a common purpose and ensure maximum driving pleasure on the boat trip: the construction and the way the drive shaft is made to rotate work differently.

Differences between electric and internal combustion engines

Is an electric boat motor worth it for my boat?

What are the advantages and disadvantages now? The most critical question for boat owners: What is better for me and my boat? To make the comparison more accessible, we will show you the advantages and disadvantages from the point of view of the electric motor.

The advantages of an electric motor on boats

The advantages of the electric motor compared to vehicles with combustion engines are manifold. From our point of view, the electric motor has many benefits, but it is not always 100% suitable. Some challenges come with electric motors. We will show you how you can quickly eliminate these supposed disadvantages with our help:

1. Volume of an electric motor

An electric motor is significantly quieter than a combustion engine! Depending on the type and structure, the volume of the motor is different. Electric motors without gears have a book of only 30-60 decibels and are practically silent. On the other hand, electric boat motors with gears are a bit louder, around 70 dB. In any case, the electric drives are significantly quieter. The noise of a combustion engine is reminiscent of the main streets in a big city. That was the reason to think about an electric motor for our boat. When we think of a boat trip, we mainly think of nature and relaxation.

Our opinion: There is no alternative to electric motors regarding volume. Except for muscle power, of course, you are doing something good for your health here!

In general, the article reflects not only facts but also our opinion. We try to be as objective as possible. As with almost Everything, there is a second opinion. From time to time, we hear statements from boat owners at trade fairs such as:

The engine must be noisy and smelly.

Can I get a speaker for the engine sound?

Electric? Then I have to talk to the others

2. Zero emissions and a clean affair

An electric motor does not produce polluting and smelly exhaust gas when driving. Studies have shown that 38 times more nitrogen oxides are released into the atmosphere due to the lack of filter systems. In addition, the engine does not need oil, which could leak.

Are you going to the lake with your family, and can you smell the gas station? For us, that was one of the most important reasons for dealing with electromobility. (There are, of course, exceptions who like the smell of a gas station.) Nevertheless, we think of you and your health.

A lack of exhaust gases or lubricants in the water significantly impacts animals and the environment. In port facilities, we too often see a shimmering film of oil on the water. In addition to the animals, it also has advantages for the water quality in your area. Especially with the summers getting hotter, the water quality of the lakes and rivers in Germany is an essential factor favoured by electric boat drives.

3. No maintenance costs and cheap operation!

An electric motor is considerably cheaper in the long term. You are spared maintenance costs and only need electricity as an energy source. Depending on the engine, electric motors can be more affordable than combustion engines right from the start, especially in the low-power range.

The larger the marine battery, the higher the cost of the complete system. When purchasing, we recommend that you pay close attention to how much capacity you need on average.

We have developed a small cost calculator for you on our website. You can compare the annual costs from the comfort of your home and see when an electric motor is worthwhile for your boat.

All you have to do is state how often you sail per year and how high the consumption of your boat is. Another interesting point: You can see how much CO2 the boat engine emits over time and how much CO2 can be saved.

Break-even: when is an electric motor cheaper?

The payback period depends on the engine and your driving style. When calculating, you compare the costs of the purchase with those of the operation: You buy a 15 hp combustion engine for €4000 and spend €800 on petrol and €200 on maintenance every year. Or you buy an 11kw (15 hp) electric motor with a 12 volt battery system for €8,000 and only spend €200 on electricity per year.

Your electric drive will pay for itself after just five years. After ten years you have already saved 4000€. Fossil fuels are a finite resource. Do you think the price will increase in the future? In the long term, we assume that petrol prices per litre will rise significantly due to a CO2 tax or something similar.

On the other hand, inexpensive solar cells can generate electricity for free. This electricity can be stored directly in your battery system.

4. Eco-friendly and ecologically sustainable

The operation is climate-neutral if you use green electricity for your electric motor. What does climate neutrality mean? No harmful CO2 emissions or nitrogen oxides pollute the air and endanger your health. In addition, pollutants such as fuel, oil or other lubricants do not get into the water. With electric motors, there is no risk of endangering local waters and animals.

It is possible to mount solar modules or small wind turbines on the boat to generate electricity on the water itself. Alternatively, you can also set up systems at the dock or on your boathouse, and you are also safe from rising electricity prices.

This is particularly suitable for houseboats with a larger roof area but also for smaller boats. Many solar panels are collapsible or can be rolled up, making them easy to install on the roof or railing of the ship.

5. No driving bans for electric boats

In the news, there is a lot of reporting about exhaust fumes from cars and thinking about driving bans. This topic is also becoming more popular on the water – boats with internal combustion engines will no longer be allowed to sail anywhere in Amsterdam from 2025. Boat engines lack filter systems for cleaning the emissions. Boat engines produce 38 times more dangerous nitrogen oxides than cars.

Of course, there are already many lakes in Germany and Austria with driving bans. We are personally confident that driving bans and higher requirements will increase significantly in the future. With an electric motor, you are on the safe side here. Especially when you are thinking about buying a new boat engine, you should keep this not-insignificant factor in mind.

6. Maintenance-free – no more stress!

You must have worn parts changed from your engine in the middle of the season. Not with an electric motor. Most electric motors are maintenance-free and have a long service life with high-quality artistry. This saves you a lot of stress. Is the engine still under warranty? Where can I have the machine repaired, and how expensive is the fun?

Perhaps you are also much more technically adept, and replacing a few worn parts will be delicate. Then it’s not so dramatic for you. We would be completely overwhelmed by that! That’s why we prefer to play it safe with an electric motor.

7. Greater safety on board

Safety is the be-all and end-all. On the road, e-cars impress with their higher level of safety. The battery should be stored dry on the water, with splashing water not being a problem. Most motors are splash-proof. Some batteries are even fully buoyant.

The fire risk is low, but we still recommend a special fire extinguisher on board to sure batteries are safe. We mainly work with lithium iron phosphate batteries. These are non-flammable and, therefore, absolutely safe.

Handling highly flammable and explosive petrol on board is no longer necessary. From our point of view, it is much more comfortable without a petrol can on board.

8. Better efficiency and faster acceleration

With an electric motor, there are significantly higher efficiencies: The energy conversion is very efficient because no idle speed is required. This means that there is already a very high torque from the first revolution, which is why a significantly higher acceleration can also be achieved with electric motors.

In practice, this certainly sounds understandable: the sooner you start, the better for you. The same can be observed with electric cars. It is not for nothing that a Tesla Model S accelerates so quickly and leaves all other vehicles behind at traffic lights. And that despite the additional weight of the 12v battery!

9. Simple operation and good handling

Operation and handling are more straightforward than with a combustion engine. Gasoline engines usually start with a choke, and you must “crack” the machine. And that often only works on the first try. You start the engine directly with an electric motor by pressing a button.

Many motors have a speed control for stepless control. The advantage is that the engine can switch between forward and reverse without shifting gears. The operation is much more intuitive and user-friendly, and the speed can be controlled better.

Another advantage of electric motors is that the motor and battery can be monitored very easily. Manufacturers often offer special functions that are not directly integrated into combustion engines.

This includes calculating the remaining range, power consumption, GPS, or autopilot. Of course, you could add these features separately to combustion engines if you wish. They are often already integrated into electric motors, and you can invest only what is necessary.

10. High flexibility: electricity anytime, anywhere

When you use an electric motor, you always have electricity on board. Other power consumers, such as heaters, lamps, cool boxes and others, can be operated via the same power circuit.

Pay attention to the required capacity early on when designing your batteries. When planning the route of your boat trip, you should also take loading points into account due to the maximum capacity.

The good thing about electric motors is: Electricity is available almost everywhere! So you can recharge the battery on your jetty and in ports, piers or at charging stations and are therefore still very flexible.