It’s been a while

But we are at it again. Working on a sustainable future of our boat! The diesel engine should go out. And in comes electric. That was already the original aim when this blog was started, back in 2010

But when can I replace the (not so) old diesel? Well, there are still quite some obstacles to take. Like

  • Charging is still an issue in the harbour
  • Costs, it still aint cheap
  • Choosing the right engine, batteries and all we need
  • Finding experts, good technical people are hard to find

Where do we stand?

Since 2010 I have written dozens of blog posts on, visited boat shows in different countries, discussed sustainable solutions with many nautical suppliers and have shown different success stories. Following industry trends, sustainability is receiving more and more information, rightfully so. But there still is a long way to go.

Looking at a simple example, our own 7m open boat. When I started writing these blogs, the boat was somewhere on the canals in Amsterdam. There was absolutely now possibility to charge batteries for an electrical powered boat, unless you were lucky enough to be docked in one of the few, often very small, harbors. That was our personal reason to postpone this project and focus on informing other and investigate the possibilities.

Charging, is it possible?

Since then, the boat moved to large harbor on one of the lakes of The Netherlands. Charging is still an issue. I want to bet that if a couple other boats on our pier switch to electrical propulsion and want to charge after a sunny day on the water, we will blow up the fuses. Supercharging, as we see on every new car these days, is not in the stars. To give you an example, I guess there are currently 8 power plugs for 50 boats…

It is possible, but still a challenge.


The costs for making a boat as sustainable as possible, doesn’t come cheap. The solutions that aim to fully replace an inboard diesel engine, including batteries, chargers and other required equipment is similarly priced as a new diesel engine. To be honest, I had expected that the costs would have come down more. An electrical engine is a lot less complex than a modern diesel engine, so what is keeping the price up so much? Is it that everything that has the label “nautical”, is immediately substantially more expensive? Or are there other good reasons for these high prices? Maybe the continued drive for sustainability in every sector, both in in the industry and for private homes, drives innovation forward and at the same time drives prices down.

The type of engine

Choosing the right type and brand of engine is another challenge. Diesel engines have a long history since it was invented by Rudolf Diesel in 1893. Since then, the engines have seen many improvements both on efficiency as well as reliability.

Electrical engines are actually a lot older, as they were first used in experiments in the 1740’s! But large scale electrical engines, first in cars and now in boats too, have only become popular in the last couple of years. Just look at the success of Tesla, which is this year only 20 years old, and had most of its succes in the last couple years.

Because boats have their own requirements, it is difficult to take an of the shelf electrical engine and install this in your boat. Which is actually the same for a diesel engine, it needs to be adapted for use on board. Some experienced engine companies use their experience to do the same with electrical engines, like for example the Dutch nautical company Vetus. They have a full range of electrical engines, including water and air-cooled engines, and everything else you need.

One of the things that is really different, is that it takes a long time to charge those large batteries, needed to sail a full day. On the road there are many fast chargers, which can charge with up to 300kW, which they advertise gives you a range of up to 300km in 15 minute. Compared to some advice about charging your boat battery:

Most marine batteries suit a 10-amp to a 20-amp charger. With a 10-amp charger, you can expect a five to ten-hour charging time for the battery from totally flat.

Boating Beast

And like I said before, I am pretty sure that would take down the wall charger in the harbor if there are a couple boats charging their batteries.

So looking at an engine combined with the battery pack, the first question is: What is the use for?

  • Fast or slow?
  • Open water or not?
  • All day, or only an hour orso?
  • How long is the boat?
  • How much does the boat weigh?
  • What is the charging capacity?

Answering these questions tells the following.

  • We go slow, on a small lake
  • I don’t see us sailing for more then 2, perhaps 3 hours on a day
  • It is an old aluminium sloop of 7.5m and weighs about 1500kg
  • About the charging capacity? I have no idea. But it ain’t gonna be much.

So this gives us some idea to work with. There will be more information, questions and problems later on. But this is a good start.

The first idea is to have a look at a simple outboard. Next to the existing diesel engine, attached to the rudder. The rudder is made of stainless steel and can easily carry the weight. This way we can test how it goes and how much power we really need.

So lastly, the experts

More and more companies are looking into sustainability around boats. Some have more experience than others, while others have very good sales stories. What has surprised me the last couple years, is that no one in the harbor seems to worry much about go out with a petrol or diesel engine. Just like that is part of the deal, while I can’t imagine something nice than go out on the water with an engine that only provides a faint whisper.

Finding the expert will be a challenge. The people I have talked to were motivated to “start doing more and more with sustainability”, at least they are honest that they don’t have a ton of experience.

In the mean time, I will doing more research and post more on the process of making our boat as quiet as the wind!