Hahtiperä: The Shipwreck That Became a Dress
In 2019, builders renovating a hotel car park in Oulu, Finland, struck timber where they expected only soil. What emerged was the Hahtiperä wreck, a cargo vessel dating to 1684 and the oldest known shipwreck in northern Finland. Maritime archaeologists spent years documenting and conserving what they could, but as with most underwater finds, not every fragment could be saved. Some pieces of wood were simply left over. Technically waste, they were ultimately headed for disposal.
Stages of processing the wood, right through to material form. By studying the wood material, researchers discovered that the pine trees used to build the vessel grew in the forests of Ostrobothnia in the 17th century. Photo: Esa Kapila, Aalto University.
The discovery of the 17th century Hahtiperä shipwreck in the depths of a renovation site in Oulu. Photo: Northern Ostrobothnia Museum.
Minna Koivikko, the maritime archaeologist who led the excavation, couldn't quite let the offcuts go. She approached Aalto University's Bioinnovation Center, where researchers had spent over a decade refining Ioncell, a fibre production method developed with Helsinki University. Ioncell uses a non-toxic ionic liquid to dissolve cellulose-rich pulp into a spinnable solution, an alternative to the more chemically intensive processes behind conventional viscose. The method already had a reputation for working with unconventional cellulose sources: old newspapers, cardboard, straw, textile waste. A 300-year-old ship was a new test case.
Inge Schlapp-Hackl processing the fibres. "This wonderful project brought together a large group of Aalto researchers from different research groups and schools,” says Schlapp-Hackl. Photo: Anna Berg, Aalto University.
Researcher Inge Schlapp-Hackl stripped the outer, weathered layer from the timber to reach the cleaner core, then had it shredded into pulp. The result surprised the team: remarkably few impurities, and easier to process than expected. Run through the Ioncell line, the pulp yielded a fibre with a silky hand and tensile strength greater than cotton, and crucially, a yarn with its own colour. No dye, no bleach. The brown tone and faint sheen are simply what three centuries underwater left behind.
Hahtiperä shipwreck dress in detail. The color of the dress comes directly from the Hahtiperä wreck. Dress designer Anna-Mari Leppisaari says that sustainability thinking has increased interest in using undyed naturally colored yarns in the textile industry. Photo: Esa Kapila, Aalto University.
That yarn went to knitwear designer Anna-Mari Leppisaari, who worked with an experimental knitting program built on an evolutionary algorithm by Severi Uusitalo. The software generates surface pattern proposals locally, without heavy computing demands, and Leppisaari used it to develop a texture referencing wood grain and digital noise. She then knitted two identical dresses on a Shima Seiki machine as single, seamless three-dimensional forms, producing finished garments with no cutting, no seaming, and no offcuts of their own.
Hahtiperä shipwreck dress. Photo: Esa Kapila, Aalto University.
One dress is now showing at Oulu Art Museum's Tomorrow's Wardrobe exhibition; its twin opens at Aalto's Designs for a Cooler Planet on 1 September 2026.
What makes this project worth dwelling on isn't novelty for its own sake. It's the chain of decisions: a conservator who refused to write off scrap timber, a fibre science team willing to test their process on an unlikely material, and a designer who matched the yarn's character with a construction method that wastes nothing. Each step depended on the last. The dress is a tangible answer to Pirjo Kääriäinen's question about why so much usable material still ends up in landfill, and a reminder that cellulose, whatever its origin, still has work left to do.
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Further Information:
UNESCO recommends that underwater archaeological cultural heritage should be left at its discovery site. However, wrecks may be raised and conserved for justified reasons. The Hahtiperä wreck was conserved because it is the oldest shipwreck discovery in Northern Finland. The preserved section is about seven meters wide and around twenty meters long. It will be displayed in the new museum building being constructed for the Oulu Museum and Science Centre, opening in the Myllytulli district in autumn 2026.
The Shipwreck Dress will be on display until 27 September 2026 at Oulu Art Museum, as part of the exhibition 'Tomorrow’s Wardrobe'.
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Read more about textiles and the role of water in Selvedge Issue 131, Flow.
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Image Credits:
Lead: Hahtiperä shipwreck dress. Photo: Esa Kapila, Aalto University.
All further images as credited in captions.