Danish record tunnel had to give way to Swedish cannons

24 October, 2023

It is the world’s longest submerged tunnel of its kind and will halve the travel time from Skåne to the continent.

But a legendary Swedish naval victory in 1644 was setting the stage for the gigantic tunnel construction in the Fehmarn belt.

The Fehmarn Belt Tunnel will halve the travel time to the continent. Graphics: Anders Humlebo/TT

-Where is the old shoreline? someone asks when media manager Jens Villemoes shows the press around the vast construction area at Rødbyhavn in southern Denmark.

-We just passed it, at the cones there, Villemoes points out.

Aerial view of the Fehmarn belt from the north. Nearest you can see the large construction area with white and blue giant tents where the tunnel elements are produced, and to the right of that the started tunnel mouth. The current ferry position is visible on the far right. The German island of Fehmarn looms in the background.
 Photo: Femern AS Via TT

Now we are driving where there was open sea a couple of years ago. The coastline has been moved half a kilometer out into the water, to make room for all the excavated material we retrieve from the seabed.

50 Eiffel Tower

The thought is dizzying. And it often does so on this construction, where most things are almost unimaginably large. In white and blue tents, which each seem to hold a small city, 89 tunnel elements are to be manufactured. Rusty rebar is stacked on every free square meter in the tents – the amount of rebar alone is equivalent to 50 Eiffel Towers.

But most of the weight of an element of at least 73,500 tons is concrete. Casting a part takes about 30 hours of concentrated work, when concrete must be poured nine meters into a form, without bubbles or other defects.

-It should be a nice, tasty concrete smoothie, says Villemoes with satisfaction.

Since such a step cannot be interrupted, the workers take turns around the clock. That part of the work is now underway.

The work on the tunnel mouth takes place well below the water level. The dams have been built from material from the seabed. In the background ferries in the Fehmarn belt. Photo: Ida Marie Odgaard/Ritzau SCANPIX/TT

15 millimeters

In the summer, the elements will be towed out into the Fehmarn belt to be lowered into an 18-kilometer-long recess on the seabed. One element at a time, precision work that takes up to a week each.

-We control the elements with wires, with a margin of error of 15 millimeters when they are fixed and then covered on the bottom, says construction manager Anders Wede.

Factor in interruptions due to bad weather and more, and that part of the construction alone is expected to take several years.

Construction manager Anders Wede and media manager Jens Villemoes in front of the emerging “portal”, the tunnel descent on the Danish side. Foto: Henrik Samuelsson/TT

Fully assembled, tested and ready, the Fehmarnbelt tunnel is not expected to be in place until 2029. Then the travel time from Copenhagen to Hamburg will be almost halved, from upwards of 5 hours to approximately 2.5. A lot of the travelers are expected to be Swedes, who save about 16 miles compared to the route over the Great Belt Bridge and Jutland that many people take today.

Perhaps best we say New Year’s Eve, smiles Villemoes when asked what date in 2029 the tunnel will be ready for inauguration.

The war came in between

Y-es, a lot can come up that causes it in the timetable.

-We had intended to buy the steel from Russia and Ukraine, says Anders Wede as an example.

-But first the pandemic came in between, then the Russian war of aggression against its neighboring country.

-Now we have to ship it in from Germany and Spain instead.

Wede claps his hands over the vast construction area, bathed in autumn sun, where signal-clad workers look like angrily glowing tiny ants against the dull-colored vast tunnel sections.

A cannon from the battle between Denmark and Sweden in 1644 is on display near the tunnel construction. Foto: Femern AS, Handout/TT
Animation showing how finished tunnel elements are lowered to the seabed. The five sealed openings are from the left expressway, service tunnel, expressway, railway and railway. Graphics: Femern AS via TT

Wreck found

Another complicating factor of a more original kind was already apparent when probing ahead of the construction over ten years ago. Divers then found a wreck that turned out to be the Swarte Arent, a Dutch ship that participated and played a decisive role on Sweden’s side in the Naval Battle of Fehmarn in 1644 – one of the Swedish Navy’s greatest military victories in history.

The victory over Denmark pushed forward the Peace in Brömsebro the following year, when, among other things, Gotland, Jämtland and Härjedalen became Swedish.

-You gave us such a beating that I don’t want to talk about it, smiles Jens Villemoes.

-But he says in any case that the discovery of the wreck meant extra work.

-You can’t just plow straight through a place like that with a tunnel, so we adjusted the draw a bit.

Thus, Swarte Arent can continue to rest in peace. Only some of the ship’s cannons have been salvaged and are now on display nearby – as a reminder that neighborly relations have not always been as good as when Danish, Swedish and German travelers soon converge on the new traffic artery.

This is what it should look like when everything is ready, animation with the tunnel mouth on the Danish side. Graphics: Femern AS viaTT

The Scandinavian mainland is connected to the continent via a series of Danish islands. There are bridges between many of them, and via the Öresund and the Little and Great Belts, it is already possible today to get to by car and train without getting wet.

But a much closer route is more directly south from Copenhagen, across the Danish islands of Falster and Lolland to the German island of Fehmarn. However, there has been a lack of a fixed connection across the heavily trafficked sea route Fehmarn belt – until now.

After long discussions with Germany, the parliament in Copenhagen decided in 2009 that Denmark builds a tunnel under the Fehmarn belt. It will be just over 18 kilometers, more than four times as long as the tunnel section in Öresund.

The Fehmarn tunnel is ground-breaking in several ways. It will be the world’s longest submerged tunnel intended for cars and trains. And the Danish construction extends three kilometers into the German Fehmarn – it is, according to the contractor, the first time ever that another country is allowed to build infrastructure inside Germany.

The budget is 7.4 billion euros (roughly SEK 85 billion). According to a similar recipe as the Öresund connection, this is paid for with loans, which must then be repaid via traffic charges. The repayment period is planned to be 28 years. What it will cost to travel under the Fehmarn belt is determined by the Danish authorities, but they have not yet specified any amounts.

The naval battle at Fehmarn was a decisive turning point in the Torstenson War between Sweden and Denmark-Norway, which in turn was part of the great 30-year war in Europe in the 17th century.

Sweden was looking to break Denmark’s grip on, among other things, the approaches to the Baltic Sea. On the morning of October 13, 1644, Swedish and hired Dutch warships attacked the Danish fleet in the Fehmarn belt. The Swedes had twice as many ships and took a crushing victory – the Danish commander Pros Mund lost 12 of his 17 ships, and lost his life in the fighting.

On the Swedish side, only one ship was lost. It was the Dutch Swarte Arent that sank after being shelled.

The Danes were so bruised after the battle that the Swedish negotiator Axel Oxenstierna was able to control much of the peace talks at Brömsebro a few months later.

Text: Henrik Samuelsson
Photo: Henrik Samuelsson/Ida Marie Odgaard/Ritzau SCANPIX/TT/Femern AS, Handout/TT
Graphics: Femern AS viaTT

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