One ship type, or several?
“Longship” is often used for every vessel of the Viking Age, but the Norse built a range of ships for different jobs. The long, narrow warship that gave the term its name was only one of them. Cargo ships, ferries and small coastal craft were built alongside it, and the most useful way to understand them is through the wrecks that archaeologists have excavated. The period is usually taken to run from the late eighth century to the eleventh century CE.
The clinker-built longship
What these ships share is clinker, or lapstrake, construction. Overlapping planks were joined with iron rivets, and the hull was then stiffened with ribs fitted inside. A single keel timber ran the length of the ship, and the stem and stern posts rose in a sweeping curve. The result was a hull that was light and flexible, which suited rough water, and that could be built from split rather than sawn oak, a method that kept the grain intact.
Clinker building was not invented by the Vikings. The Nydam boat from Denmark, of about the fourth century CE, shows the technique in an earlier form. The Norse perfected it, and the clinker-built longship became a symbol of their raids and travels.
What the Gokstad ship shows
The Gokstad ship, found in a burial mound in Norway in 1880, was built around the end of the ninth century CE. It is about 23 metres long and around 5 metres wide, with a shallow draught. It had 16 oar holes on each side, giving 32 oars, and a single mast carrying a square sail, which was probably made of wool. Steering was by a side rudder fitted to the starboard side near the stern, instead of a rudder on the centreline.
The hull is a good example of the flexibility of clinker building. Reconstructions suggest the hull flexed noticeably in a seaway, and a full-size copy sailed across the Atlantic in 1893. The Gokstad ship and the earlier Oseberg ship are discussed as part of the wider topic of the Viking ship burials, which also tells us about the people who were interred with them.
What the Skuldelev ships show
The Skuldelev ships, found in Roskilde Fjord in Denmark in 1962, supply a very different view. Five vessels were deliberately sunk, probably in the eleventh century, to block a channel. Between them they cover several types: a large ocean-going cargo ship, a bigger warship, a smaller trading vessel, a small warship and a coastal craft.
The ocean-going cargo ship is the best-known example of the knarr. It was wider and deeper than a warship, with a high freeboard and a large central hold, and relied mainly on sail, with only a few oars for manoeuvring in harbours. Knarrs carried goods, livestock and settlers on routes across the North Atlantic. The larger Skuldelev warship was built of oak that dendrochronology links to the Dublin area, a reminder that the Norse world was widely connected.
Rowing and sailing
A warship was designed to be fast and to land in shallow water. Rowing allowed a crew to move against the wind, enter rivers and approach a beach without a harbour. Under sail the ship could cover long distances with less effort. Both worked together, and crews could switch depending on conditions.
Exact speeds are uncertain. Modern replicas have reached sustained speeds of several knots under sail in good conditions, but a replica is only an informed estimate of the original. Specific claims about top speeds or crew sizes should be treated with caution. Warships such as the one at Gokstad probably had a crew roughly matching the number of oars, with extra hands, though historians differ on how crowded the ships were.
Longships, the sea and other traditions
The longship was the northern equivalent of the Mediterranean galley, but the methods behind it differed. Mediterranean builders, as the survey of ancient shipbuilding methods explains, moved from planks pegged with tenons to frame-first construction, while northern builders continued with clinker. The two traditions eventually met, and from the late Middle Ages, northern ships began to adopt features from the south.
The voyages that these ships made are a separate story, which is told in the article on Norse seafaring skill, along with the crews, navigation and the settlements in Iceland, Greenland and North America. Here it is enough to say that without a seaworthy, flexible hull none of them would have been possible.
Reconstructions
Several modern reconstructions have tested what the wrecks suggest. Danish teams built full-scale copies of the Skuldelev ships at Roskilde, and one of the largest, a replica of the big warship named Havhingsten fra Glendalough, sailed from Denmark to Dublin in 2007. These projects are examples of the experimental archaeology ships that supplement excavation, helping to show how a hull behaves, though they cannot prove how the Vikings themselves used it.
Reconstructions also remind us that the finds are accidents of survival. Ships buried in mounds were prestige vessels and may not have been typical working boats, and those scuttled in the fjord were already at the end of their lives. The surviving record still leaves room for types that archaeology has not yet found.