The clucking from the boarding when planks that overlap meet the water surface is the clinkers’ very own melody. A “jingle” for the ancient clinker technology that has followed from the flexible battleships of the Viking Age to today’s folk boats. The oldest find of a clinker-built ship in Sweden is the Äskeskärr ship, which was found in Ale municipality just outside Gothenburg. It was dated to the 930s, and a number of ship finds have been made even after this.

In December last year, the clinker boat tradition was inscribed on the UN agency UNESCO’s list of humanity’s intangible cultural heritage.

– Unesco states that this is an important cultural heritage, I would say that the listing shows that the clinker boat tradition has an invaluable importance. It is a knowledge that does not sit in books or theories, but in a skilled craftsmanship that does not survive without committed people, says Fredrik Blomqvist, curator at the Maritime History Museum.

The placement on the list applies to the building tradition in the Nordic countries, where the governments supported the application to Unesco. Fredrik Blomqvist hopes that the attention it gives will increase interest in the boats and construction technology, and make more people want to learn the craft. Pelle Nestorzon, teacher at Stensund Folk High School’s boat building line, hopes the same.

– It raises the feeling that what we do is important, that this knowledge is based on something valuable. It feels very nice to be a carrier of culture, he says and steps up the steps to the house of the boat builder line.

Warm winds sweep over the Baltic coast, just outside Trosa. It smells of tar and spring, and it’s easy to feel the urge to turn one of the finished clinker boats outside the house on the right keel and head out into the archipelago, which starts just a few hundred meters away. This is also what each course start for the boatbuilding line begins with: two weeks at sea for all 16 new students and their teachers. There, students get the chance to directly acquire some sea experience, get a feel for how the clinker boats work in a purely practical way and meet the people of the archipelago to learn more about the building tradition.

– From the archipelago residents, they hear, among other things, about how the boats have been used historically. A decently large property here in Sörmland had a large increase, a small increase and perhaps a middle increase. The big onion could be used to transport a cow to pasture, the small onion the children might have when they rowed to school. These are utility boats that were really used in everyday work, they can be said to be a bit of “the archipelago’s tractors”, says Pelle Nestorzon and smiles broadly.

Concentrated activity prevails in the boat building premises. Four clinker boats have emerged since the start of the autumn term and as the summer graduation is now approaching, about half of the boarding remains, and then the interior. The work is carried out in principle with the same tools and technology as before in the history of boat building, except for the sparse use of band saws, planer and planer. The wood for the tables is based, bent by steam baking with the help of a wood-fired steam boiler, and put in place with clamps, to cool in just the right soft line for just the variant of clinker boat that is built.

– Can you look a little at the angle here? It will be difficult with the planer here towards the beak. There are such small margins, I do not want to happen to take too much, says Alva Wickbom and strokes with her fingertips along the spun, the seam that is to be used when attaching the planks.

She and Alexander Herner are well placed in the boarding of Stensundssnipan, which is their degree project, and they can afford to be extra careful. But it is also about millimeter fitting, where the planks should end tightly in the boarding. To some extent, it is possible to save a mismatch, but not to any great extent.

– In the landing, we tar both tables (the planks) and put yarn in between as a seal. If there is still a gap, we have rackar putty, a paste that we can seal with that has about the same consistency as ordinary linseed oil putty, says Alexander Herner.

– It is also possible to make your own pasta from chalk and linseed oil, Pelle Nestorzon suggests.

He cuts the spun and carves one last millimeter with the carpenter’s knife, then the pine plank fits like a piece of the puzzle in the boarding. The students build four different variants of clinker boats originating from the local area in Södermanland. According to Pelle Nestorzon, it is relatively easy for a trained eye to see where in the country a clinker boat is built.

– Even if the construction technology itself is the same, there are clear geographical differences in material selection and construction. As an example, we have a lot of pine here in Sörmland and have mainly built boats of that type of wood, while in Blekinge historically there was a lot of oak to take off, and the clinker boats in Norrland are normally made of spruce.

The appearance of the boats varies based on which boat builders have been hired, but also based on the users’ needs.

– Gotland clinker boats, for example, have several small sails, as they must be able to be torn quickly in severe weather. In areas where it is possible to sail in the shelter behind a skerry, the sails are larger. In Bohuslän, where there is a rougher lake, slightly larger boats were built, and preferably with more stable stumbling blocks (a perpendicular joint that lies over the lowering tray behind). And in the Faroe Islands, which are completely surrounded by sea, the clinker boats are very long, but light, because they need to be able to be carried up in protection on land, says Pelle Nestorzon.

Before the Iron Age, wooden plugs, dowels, were used to hold the clinker boats together, or they were “sewn” together with roots, but already the Vikings carved their ships together with iron nails – and later copper. At Stensund’s boat building line, students start from scratch, from sawing up the wood to building the scaffolding on which their boats will be constructed – to sewing sails, beating ropes and boiling tar. In addition, some fittings are manufactured in the school’s small smithy, Pelle Nestorzon’s teacher colleague is a trained blacksmith.

The basic idea is that the craft should sit in the hands, in a sense of how the wood is handled without mechanical aids. In addition, there is a great acceptance of making mistakes and thereby learning by fixing what has gone wrong. All in all, it provides an important basis for craftsmanship, says Pelle Nestorzon.

– This education is intended as a jump into reality, where students go one year of basic education and then can go another year with any specialization. It is probably difficult to make a living from building new boats, but in renovation there is a lot of work for our students. Obviously there is an interest in this type of boat building, we are almost always fully in our training.