‘Every time you turn on your engine, the exhaust water makes the sea more acidic’

Solo sailor Sidse lives aboard her 31-foot yacht in Scandinavia and reflects on the impact of cruisers on the marine environment

The sun shines bright in the sky and the gentle wind moves a lock of hair on my cheek. I turn the wheel, tack and pull the sheet towards me. Carefully I watch my electronic chart, because I’m beating, leg after leg in the narrow straits between the islands on the Swedish east coast.

Behind me I hear the low humming of an engine, and on my next tack the sailor speeds up, turns his head and gives me a strange look, as if I am the one who is behaving weirdly. ‘Tacking is primitive,’ one of my friends said this summer. I was stunned. Really, because I couldn’t disagree more.

Beating to windward is a basic and fundamentally necessary skill for a sailor. And as I’m tacking my way south through the Swedish archipelago, I’m overtaken by many sailors under engine. My reaction is: ‘Why? It’s a beautiful sunny day, the sea is flat, and you have already paid an astronomical amount of money for sails and probably had them shipped around the world to get to you – why don’t you use them?’

Every time you turn on your engine, the exhaust water makes the sea more acidic. This is endangering marine life because most fish have evolved to exist in a more alkaline environment.

Of course, the small 21hp three-cylinder engine in my tiny boat hardly pollutes compared to cruise ships and cargo containers. But it’s not about the amount; it’s about awareness. The sails are the heart and soul of a sailing boat.

I generally believe that if we start our awakening here, then the awareness about other topics of environmental impacts will also begin to rise up and be increasingly discussed in boat yards and sailing clubs.

Sail to help the sea

Two months later I’m resting my back against the cabin top, nestling a cup of coffee between my hands and feeling the September sun slide across my face, as the boat gently moves in the shifting wind. I’m at anchor in the local bay across from my home port. A sea bird screams above my head and dives to catch a fish. That’s when I notice it – around the boat small circles disturb the mirror-like surface, I rise and stare. It’s a fish gasping for air.

I know this fish. It’s a flounder, but it doesn’t belong here. Normally I only see it when I am silently gliding above the sandbanks carefully scanning the sea bed for pairs of black eyes.
Now they have fled the bottom.

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For the past three years, I have been cruising the Baltic Sea, from the Riga Bay to the Finnish Gulf in my Bostrøm 31, a Swedish design from 1976. In and out between the islands in the Swedish archipelago and my home in Denmark. Summer and winter, and summer again, I sail here. And every summer, I see the clear winter waters turning murky with algae. But this is the first time I have seen the effects of oxygen depletion.

The Baltic Sea is the most polluted sea in the world. What a record. This tiny sea is special because it’s almost completely surrounded by land. Land is what created a unique environment of brackish waters, whose salt concentration is limited to whatever the winter storms can blow through the narrow straits between the islands of Denmark.

The marine life living here is completely adapted to this environment. However, rivers flowing into the brackish waters not only balance the salt level, they also carry excess nutrients from agriculture into the sea, creating algae growth and eventually causing oxygen depletion. This is how the world’s least salty sea is turning into a ‘dead’ sea.

Nothing makes you more aware of your resources then when carrying them home yourself. But now you might ask: ‘What does this have to do with me?’ You’re not a farmer, you are a sailor. But it is your business. Because you love the sea, and while it’s mostly a beautiful reflection on the outside, beneath the surface, it’s in dire need of our help. And you, sailor, you can sail to help it.

You can sail and you can tell

One of the hidden advantages of being a small-boat sailor is the constant lack of resources. I don’t have space for a watermaker on my 31-foot monohull, and I most certainly can’t waste diesel on a generator.
I realise that water and fuel are limited resources.

Boat life in summer is easy. Sail when there’s wind, stay at anchor in the endless Scandinavian summer nights. With my 120-watt solar panels, I can live an almost energy self-sufficient life. It is such a freedom – depending on no one, only seeking port, when searching for company, and telling the stories of places protected by law and those which should be.

But I live on board all year and winter is a completely different story. In order to maintain a relatively comfortable life on board, I depend on fossil fuels and shore power to keep me warm. During the winter, water and diesel are not available on the dock due to frost – and that means I have to carry water and fuel in 20-litre canisters a couple of times a week.

It’s heavy. And I can assure you that nothing makes you more aware of your resources than when you have to carry them home yourself. This has pretty quickly taught me not to waste anything on the boat.

Fossil fuels are very far from sustainable. I wish it could be different. It’s my hope that one day we will have sustainable solutions for winter boat life as well, but this too begins with awareness. In the end, it’s the awareness that will push science to create sustainable solutions regarding problems like energy resources, waste water and toxic antifouling.

This article is entered into the Brian Black Memorial Award 2025 supported by Coppercoat.

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