They have long since internalized the old concrete construction adage “It depends on what you make of it”.

And so the students, who are at home in the Department of Civil and Environmental Engineering at the Darmstadt University of Applied Sciences, have been making sure for almost two decades that the message of the domestic building materials industry, which is used as an advertising slogan, is not forgotten.

The next opportunity to do this is on June 10th and 11th, when the 18th German Concrete Canoe Regatta starts on the Beetzsee in Brandenburg an der Havel.

As usual, the Darmstadt inventors want to start the race again with two different boats made of concrete.

Experience has shown that it is not just about speed on the zigzag course to be mastered, but also the skill of the amateur paddlers, especially when it comes to turning maneuvers on the water.

Markus Schug

Correspondent Rhein-Main-Süd.

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Even a sporting defeat, which is not exactly improbable, could be overcome given the 45 registered racing canoes made of concrete.

Many different designers from the Netherlands, Austria, Switzerland, Turkey, Hungary and Poland are taking part in the competition, which has been on a three-year break due to the corona pandemic.

For most participants, the idea behind the project is more important than the optimal paddle stroke, which according to the rules has to be done while kneeling.

With their two canoes, which were officially christened with sparkling wine on Tuesday on the university grounds and henceforth bear the names of the gods "Pegasus" and "Hades" borrowed from Greek mythology, the 30 or so master builders from southern Hesse want to win at least one design prize.

"Ernie and Bert" would have done well

The long gallery of ancestors in the basement of the atrium building B 10 on campus is still reminiscent of creatively and functionally designed winning boats from earlier days of competition: the model couple "Day and Night", for example, which could hardly be developed in a more contrasting way, but also the Sesame Street duo "Ernie and Bert” would have done well at the time, said Regina Stratmann-Albert, a professor in the architecture department who specializes in building materials, when presenting the current fleet.

And the "Schland" boat, which is well worth seeing and is reminiscent of the 2006 World Cup, was also a creative stroke of luck.

"We're constantly working on the limits of what's possible here and have to experiment, that's a bit of student research," says her colleague Albrecht Gilka-Bötzow, who also specializes in material issues and who has been working at the Darmstadt boat building for the third time, this time in a managerial position was involved.

The hulls of the two canoes are just six millimeters thick and are made like wafer-thin but durable skins using filler and glass fiber fabric.

The installation of benches or stabilizing rods is not permitted.

Measures against spontaneous sinking

Large polystyrene blocks, on the other hand, must be carried by all regatta participants as a precautionary measure so that the heavyweights, which weigh between 50 and 250 kilograms depending on the model, do not sink to the bottom of the lake forever in the event of an accident, but can also be salvaged again if necessary.

"In the laboratory, we developed our own recipe for concrete in extensive tests," revealed student Ina Oelkers: "Until we had achieved a lightweight concrete mixture with which we could build our canoes." In the water hall belonging to the campus, the "white Pegasus" and the "black Hades" have already been checked for their ability to swim.

At the same time, the participating students, who want to compete in several races in a few days as women's and men's teams, trained in real canoes on the Altrhein.

At least when it comes to sustainability, the young engineers hope to be able to convince the jurors in Brandenburg: After all, no epoxy resin, which is considered hazardous waste, was used in the manufacture of the “Pegasus” model.

Instead, a wooden formwork was made and recyclable rubber mats were also used.

When building the "Hades" boat variant, phosphorescent glass was worked into the concrete filler mixture as a special effect, so that the canoe "glows mystically green like the night sky of the underworld" in the dark.

It only remains to be seen how the gods will react when the people of Darmstadt make their way to the finish line in their two concrete racing canoes.