The delicate, dramatic art of oak splitting, hacking in half a trunk 10.5 meters long, has begun at the Viking Ship Museum in Roskilde. Using the same methods employed by Viking boat builders 1,000 years ago, experts are preparing wood for the construction of a replica of Skuldelev 5.

Medieval Roskilde

The Viking Ship Museum is centered on the discovery of five Viking ships at the nearby Roskilde Fjord in 1962. These ships were named Skuldelev after their respective finding location and were assigned different numbers for identification.

The Skuldelev ships were deliberately sunk just north of Roskilde in 1070 in order to block the passage of the Peberrenden waterway and defend against potential invasion. 

Each different in character and purpose, the vessels have given up a wealth of information from several points of view.

Capital of Denmark from the 11th century until 1443, Roskilde was a vital trading center during the Viking era for routes over land and sea. Founded by Harald Bluetooth in the 980s, it was made a diocese by King Cnut nearly four decades later.

All five Skuldelev ships are displayed in the museum's Viking Ship Hall after being excavated, raised, documented, conserved, and pieced together. This initiative provides family-friendly entertainment at the boatyard, allowing visitors to watch the team work.

Over time, this will reveal deeper secrets into how these vessels were built. Reconstruction is expected to last several years.

Skuldelev 5 was a smaller warship built in Denmark around 1030. For its reconstruction, the boatbuilders set off for the forest at Vallø Stift in search of trees of suitable quality and dimensions needed to build a Viking ship.

Boat builders apply Viking Age techniques, meticulously splitting timber, a critical step in the enduring art of shipbuilding. Photo: Viking Ship Museum in Roskilde via Facebook

How to build a Viking ship

The different parts of the ship make different demands on the material. 

Some parts – such as the characteristic prow, the hallmark of a Viking ship – require a large tree, which has been grown in a shape that can accommodate the curved lines. Other parts, such as the planks for the hull, require a large, straight-grown tree with an even course of fibers and without too many side branches and knots.

Provided with a wealth of information about and drawings of the original Skuldelev 5, construction manager Martin Rodevad Dael explained the task at hand: "It always takes a little time to find the right trees in the forest, and it is important to seek out select trees for felling. They must fit the dimensions and possess top-quality wood."

In fact, there aren't too many left: "Most are what we call flådeeg, trees that were planted at the beginning of the 19th century after the loss of the Danish fleet. So they are around 200 years old. And when oak trees get that old, they become more vulnerable to rot. So we look carefully at their growth, condition, and appearance to find shipbuilding material."

Back in February, Martin and his team managed to find two suitable oak logs: the first was split at the beginning of June, and it has provided material for the ship's stern and planks. Now the boatbuilders are fully engaged in adapting the next log, hopefully providing enough material for the rest of the ship's planks.

"The timber chosen for the plank material is very nice. It was planted in 1830, with a length of just 10.5 meters and a diameter of around 1 meter. We are eagerly awaiting the opportunity to observe how it will be split."

The last tree left

"It will likely be the last large trunk we will split in connection with the construction of Skuldelev 5, and it is quite important for us that the entire construction team participates in the process. This way, we can ensure a transfer of experience and know-how regarding splitting to the next generation of boat builders here at the museum."

"The saw wasn't used in Viking Age shipbuilding, so the whole process of splitting is absolutely fundamental to our work in reconstructing full-scale Viking ships. To achieve the best results, we must use the same techniques, types of materials, and tools as they did in the Viking Age. And that means that the trees must be split - first in halves, then in quarters, then in eighths, and so on – just like when you split a layer cake."

However, it requires a little more work to split such a trunk. With a weight of around 6.5 tonnes, it's massive, and the boat builders have to work their way through it.

They start by opening a small crack in the root end of the oak trunk, and then slowly – with bigger and bigger wedges and masses of heavy blows with clubs – they force the crack further into the trunk until the massive trunk splits in two.

Then, they continue to split down into smaller dimensions by the same method. The claw pieces are then chopped down to size and shape with axes before the finished planks are ready for adaptation and assembly on the ship.

Visitors can follow the construction progress at the Viking Ship Museum every summer until 2028, from 10 am to 5 pm daily.

English-language tours, each 50 minutes in length, are available until August 31. Tour times: 11 am & 1 pm at the Viking ship hall/museum lake; Noon & 2 pm at the Shipyard.

Viking Ship Museum, Vindeboder 12, 4000 Roskilde, Denmark.

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