SkelETHon wins 1st Prize for Design Innovation at the 16th Concrete Canoe Regatta in Germany

3D printed plastic formwork for a fully-functional concrete canoe.

the skelETHon team at the awards ceremony in Cologne Beton Kanu Regatta

The Concrete Canoe Regatta

Every other year, a two-day long concrete canoe race takes place in a city in Germany, bringing together a fun sporting competition and the latest advancements in concrete technology. This year, over 1’000 participants from universities from all over Europe raced 90 boats made entirely out of concrete on the Rhine river in Cologne. The teams competed for the lightest, fastest, most beautiful, and for the most coveted award – best design innovation.

The keel of the concrete canoe viewed from above DBT

ETH collaboration   

Since 2005, ETH has consistently taken part in the concrete canoe regattas with great success, and this year ETH won the 1st prize for Design Innovation for the 3rd year in a row. SkelETHon, the 114 Kilogram concrete canoe, was a collaboration between DBT – who provided the computational design and digital fabrication expertise – and the PCBM Group – who developed the concrete mixes and processes used in the construction of the boat.

The 3D printed plastic formwork of the concrete canoe DBT

Design innovation

In the past, the Concrete Canoe Regatta has already served as prototyping framework for emerging research projects at ETH, such as Mesh Mold and Smart Dynamic Casting, which have become in the meantime successful, mature researches. This year, Free Formwork, a research project developed at DBT was used to build a boat which was highly praised by the jury for the unique design approach.

The fibre reinforced concrete three dimensional skeleton of the canoe, designed through topology optimization algorithms DBT

The four meter-long boat has a stiff steel fibre-reinforced concrete inner skeleton, covered by a two to three millimetre-thick waterproof concrete skin. The skeleton is designed using topology and shape optimization algorithms which reduce the material of a traditional canoe design and redistribute it in a skelleton-like structure in order to maximize the stiffness of the boat.

skelETHon ready for being transported from Zürich to Cologne DBT

For the fabrication of this skeleton, a submillimetre thin plastic formwork was 3d printed and cast in ultra-high-performance fibre-reinforced concrete. The formwork for the entire boat weighed just over four kilogrammes and a precise, high-resolution surface texture, with details as small as half a millimetre, was transferred to the concrete skeleton to increase the contact area with the outer skin.

High resolution texture on the skeleton, for a better contact surface with the concrete skin DBT

The construction process made possible a highly complex concrete skeleton with bones as thin as 15 millimetres in diameter which would be impossible to fabricate with any other digital fabrication technologies. 3D printing, a precious fabrication process, was used minimally, but had a significant impact on the overall design.

The Bow of the concrete canoe skeleton, with 0.5 millimetre texture details DBT

Commercial Partners:

Sika AG, Holcim, Allplan, RooieJoris, Specht-Technik, German RepRap

Physical Chemistry of Building Materials (Prof. Dr. Robert Flatt):

Nicolas Ruffray, Heinz Richner, Dr. Timothy Wangler

Digital Building Technologies (Prof. Benjamin Dillenburger):

Andrei Jipa, Mathias Bernhard

Bachelor’s thesis students:

Moritz Studer, Oliver Wach, Kathrin Ziegler


Matthias Leshok, Ioannis Fousekis, Lex Reiter (PCBM), Andreas Reusser (Concrete Lab), The Concrete Canoe Club Zürich (Pirmin Scherer, Lukas Fuhrimann, Hannes Heller, Patrick Felder, Jonas Wydler, Jonas Henken, Andreas Näsbom, Anna Menasce, Caterina Rovati, Roman Wüst, Pascal Sutter, Thomas Rupper, Jonathan Hacker)