Photogrammetry is the technique of taking multiple overlapping photographs, which can be processed to generate a 3D scale model of an object.

In this case, the object is a replica of one of the five Viking ships dating back to 1030, recovered just off the coast of Skuldelev on Roskilde Fjord in 1962 and put on display at the museum.

Reconstruction at Roskilde

The reconstruction process is carried out at the boatyard for the public to view from May to October.

This is the first time the expert team at Roskilde is applying this type of documentation technique to one of its full-scale reconstruction projects. 

Maritime archaeologist Kirsti Pedersen will follow the construction of the ship throughout the entire build. Her work will result in significant contributions to the project in terms of research and dissemination.

The final model can be used as a benchmark to analyze the manner in which the hull form "settles" once the ship is taken into use.

It will also allow the crew to create a step-by-step animation of the construction process, with all the realistic details of tool marks, knots, and so on, that exist on the surface of the individual components for dissemination online and in exhibitions.

The final 3D model can show how the ship's hull changes over time and can be transformed into an animation showing the construction process in detail.

Cloudy skies are preferred for this work to prevent sun reflection on the oiled timbers and avoid casting shadows, ensuring consistent image quality for the model. 

Such conditions this week have allowed Kirsti to start the painstaking operation without the variations in tone and color that would disrupt the appearance of the model when the images are stitched together.

To achieve an accurate 3D model of the ship, a rigorous process of photogrammetry is employed, converting overlapping images into a comprehensive digital representation. Photo: Tríona Sørensen / Vikingeskibsmuseet i Roskilde

Shipbuilding 1,000 years ago 

Why was Skuldelev 5 built this way, with a mixture of new and old wood? What challenges did that choice create for Viking Age boat builders?

What can the ship's construction tell us about how – and how much – the vessel was used during its lifetime? 

And what does that say about the use of warships in the 11th century?

To investigate these questions, the museum's boatyard at Roskilde has embarked on an experimental archaeological project with a full-scale reconstruction of Skuldelev 5. 

Work began in the summer of 2022, and construction is expected to span over the next four years.

The original Skuldelevs were built around the year 1030, the final phase of the Viking Age

With their advanced maritime technology, Scandinavians have become important players on the European political stage. 

Their violent raids transitioned into outright conquests, and multiple trade networks were subsequently established.

Several types of ships were developed for specific purposes: large, powerful knarr (cargo ships) for trade voyages on the high seas; small, maneuverable fishing boats for use on fjords, rivers, and inland waterways; and, not least, the famous and feared warships.

These were long, narrow, swift ships equipped with many oars and a single square sail designed for the efficient transportation of warriors.

The Skuldelev 5 reconstruction, which began at the Roskilde boatyard in 2022, is projected to achieve its authentic representation over the next four years. Photo: Tríona Sørensen / Vikingeskibsmuseet i Roskilde

Unique features of Skuldelev 5

In the case of Skuldelev 5, its hull contains some quite unusual details, making the ship something of an exception to the rule compared to other warships of the Viking Age.

This ship was built from the outset with a mix of new and reused timber. 

Planks were taken from another ship and adjusted so that they could be used again in the new one.

One of these planks bears carved decoration in Ringerike style – the only decoration of this kind we see surviving on Danish Viking ships. 

The hull also contains a wider range of wood species than you typically find in Danish ships of the period. 

It is built primarily of oak but also has pine and ash as part of the planking material, and the quality is generally lower than that seen on other 11th-century warships.

The ship was in service for about 30 years, and many repairs were carried out along the way. 

But it was not to end its days by being chopped up and burned like many other old wooden ships. 

Instead, the ship was towed out to the water just off the coast of Skuldelev on Roskilde Fjord. 

Here, it was filled with stones and intentionally scuttled to become part of a barrier system on the fjord formed by five ships.

There, after many centuries, the Skuldelev ships again saw daylight in 1962. They were excavated, raised, documented, conserved, and reconstructed.

Today, all five ships are on display in the Viking Ship Hall at the museum – this one was given the archaeological name of Skuldelev 5.

You can follow the reconstruction project here.

Viking Ship Museum, Vindeboder 12, 4000 Roskilde, Denmark. Open daily, 10 am-4 pm.

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