Vikingeskibsmuseet i Roskilde

This week lead shipwright Joe Connor and I had the privilege of visiting the Viking Ship Museum in Roskilde, Denmark to study ancient and medieval Scandinavian boat building techniques. Our days on the fjord were spent helping along in some replica vessel construction, conversing with the museum’s staffed shipwrights, and sailing aboard a 1030 A.D. replica vessel- we left immensely inspired. At Roskilde they follow a strict observance of historically accurate material usage and methodology grounded completely in archaeology and historical research. The museum is primarily focused on five Nordic vessels scuttled in 1070 which were fully excavated in 1962. The vessels are known collectively as the Skuldelev ships and replicas of all five vessels have been built and sailed extensively. The building and sailing of these vessels is taken with great care and all findings are recorded as this direct experiential process is seen as being a practice of archaeological research in itself.

The five principle ships were meticulously reconstructed and able to take on their original shape through the preserving of their material with polyethylene glycol and form support using elegantly constructed steel armature. They constitute the museum’s primary exhibit in a beautiful gallery space overlooking the fjord which kept them secret for nearly 1000 years.

The main museum building beautifully showcasing the Skuldelev ships

Day one was spent working with Sorren and Birger two of the museums lead shipwrights. We learned a great deal about their usage of treenails and helped hand carve a few ourselves. The ancient and medieval Nordic people fastened frames and planks using goat willow treenails with the outboard face left with a proud rounded shape like a carriage bolt or peened over rivet. The inboard face to be wedged was bored out with a spoon auger to create a subtle oval shape to better allow the splitting of the treenail by the wedge. Treenail fastening is of great interest to us as the Maryland Dove will be primarily fastened using a variation on this technique.

Dove lead shipwright Joe Connor and lead builder at Roskilde, Birger Andersen discuss Viking ship building techniques. Joe is holding a common spoon auger from the Viking age used to bore holes for trunnel fastening.

Large knees of the coveted choice quality Danish oak used for floor timbers.

All of the vessels built at Roskilde are made using tools that were built with patterns from the historical record. The Nordic people of this time period did not yet have saw mills so every piece of the boat is split out by hand along the grain using edge tools. Scavenging for material with the absolute perfect grain structure is even more essential for them than it is for us for this reason. The vessels are built using primarily Danish oak, Norwegian pine, and Ash. They also make use of a very peculiar birch root for their steering oar pin. Virtually every piece of the boat is covered in pine tar with brightly colored paint applied to the topsides of war vessels. Everything used in the direct construction all the way down to the clamps temporarily securing the split clinker planks or cloverboards themselves are carved out and made using splitting and edge tools. It will be noted that some preliminary work in the reduction of material is performed using the band saw, table saw, and chainsaw.

As for the rig: there have been no hemp ropes or fibers found on any of the viking ship excavations and to my surprise the primary cordage material of choice was lime bast, the sturdy fibrous substance derived from the soaking of linden or “lime” tree bark. The bast fibers are woven into yarns, the yarns into strands, and the strands into common right hand laid three strand rope. Presumably this material would have been used for both running and standing rigging. Our hosts at the museum commented on the materials rot resistance compared to hemp. The Vikings also build standing rigging out of elk and seal hide and running rigging and bolt ropes out of wool and horse hair. Sails were of wool with horseneck fat and tar, or of bark tanned linen. It should also be noted that the Vikings had already in 800AD made use of reefing nettles to shorten sail, a technology that is occasionally believed to have followed the use of bonnets. The development of bonnets developed during the 16th century and really only lasted for about two hundred years as a presumably lesser successful alternative to reefing nettles.

Elk hide rope, common during the Viking age

Linden bast rope, the most commonly found rope of the Viking period in the archaeological record

Linden bast stripped away from the bark after soaking

Day two Joe and I were invited to sail aboard the Skuldelev 1 replica, Ottar. Skuldelev 1 was the first excavated vessel out of the five and represents a common cargo ship of 1030 AD. We were surprised by her sensitivity while at the helm and by her weatherly abilities considering her single large square sail situated nearly dead amidships. We had winds of 10-15 knots and were clipping along very comfortably passing all of the modern glass boats we came upon. Ottar’s very secure motion through the mild but existent sea state was certainly noteworthy. We were each given the helm for a bout two hours, taking her through a few tacks and wearing ship a number of times as well. Sailing a relatively large single square sailed vessel is quite an experience as so many associations of anxiety and security are reversed when compared to a fore-and-after. Waring, or jibing, is the safe sail evolution rather than tacking; and sailing upwind in a blow is the point of sail to remain particularly cautious on rather than sailing deep, as one can accidentally get caught with the sail aback which could lead to a capsizing. In fact, in order to tack, the vessel has to pass through the wind far enough for the sail to back itself to aid in bring the ship about far enough to then “switch tacks”, that is, literally bring the previously to-leeward corner to windward. This is the etymology of “tacking”, to switch the tack or forward running line from being in use on one lower corner to the other, and likewise with the sheet. The final characteristic of sailing this vessel which may feel alien to the modern sailor is in the experience of considerable lee-helm when sailing upwind, a phenomenon that a modern sailor seldom encounters. The steering oar or rudder was sensitive yet had a very limited range of movement, much of the success of sailing a vessel of this type relies on proper sail trim, as well as an efficient weight distribution in the placement of the crew in the vessel.

Sailing close to the wind on Ottar.

The Roskilde Museum provides us with a rigorous example of a museum really guided by archaeology, in fact, it is essentially a kind of Viking archaeology museum. Our experience in Roskilde shed light on ancient building techniques, some of which would endure all the way to our time in the early 17th century. Build detail aside, the museum gave us a new view into a measured experimental archaeology. As mentioned in previous posts, a large sprit rigged boyer type vessel such as the Dove, has not been sailed in modern times. A relatively substantial task within the view of our project will be in adequate sea trials and subsequent adjustments in rig. Recording the Maryland Dove’s level of efficiency, comfort, and ease of use in a variety of conditions and sail configurations will be critical to properly understanding the design of the ship and her place in the 17th century as an effective coasting vessel.

While the principals of building at the CBMM shipyard provide us with our own distinctive style of operation, a holism appears in Roskilde at the Viking Museum, the spirit of which we will strive to carry with us in the build of the Maryland Dove.

The second replica of Suldelev 3, the current project in the boatyard. The first replica has suffered from fastener deterioration. This vessel will be fastened with bronze as the museum conducts research into the specific qualities of the iron used by the vikings.