Skill, not just ships
The vessels of the Viking Age are well known, but the voyages depended just as much on the people aboard. The Norse, from Scandinavia and later their settlements, crossed open water on routes that covered hundreds of miles. They did this without a magnetic compass, charts or any of the instruments of later centuries. How they managed is partly a matter of careful inference from sagas, place names and archaeology, and partly a matter of admitting that evidence is thin.
Finding the way
Norse navigators probably relied on observation and experience. The sun by day and the stars by night gave a general sense of direction and latitude. Clues from nature, such as the flight of birds, the colour of the water, drifting seaweed and cloud formations above land, helped to indicate the approach to a coast. The sagas mention the sailors’ use of such signs, including the story of releasing ravens to find land, associated with the settler Flóki.
Sailing directions were passed on by memory. Written accounts, like the Icelandic Landnámabók, a medieval record of settlement, include sailing times between places measured in days. These are not precise, but they suggest that routes were known and repeated.
One often-quoted idea is the “sunstone”, a crystal that could allow the sun’s position to be found on a cloudy day. It is mentioned in a saga, and a crystal was found in a wreck from the Elizabethan period, but whether Vikings used such devices in practice is debated. Similarly, a wooden disc fragment found in Greenland has been interpreted as a navigational aid, though this reading is uncertain. A fuller picture of the topic is given in the article on maritime navigation history, and the magnetic compass is a much later arrival in northern waters.
Crews and organisation
Ships were crewed by a mixture of kin, neighbours and followers. A warship might be manned by a chieftain’s household and men raised for a particular expedition. Later, in Scandinavia, kings organised levies of ships and men, a system often called the leidang, which required coastal districts to provide a vessel and crew. Details vary by region and period, so general statements should be treated carefully.
Aboard, crew members probably shared the work of rowing, sailing and bailing. Cargo ships needed fewer people than warships because they relied on the sail. Trade, raiding and settlement all used the same sea skills, and the same person might do each at different times.
Westward to Iceland
Iceland was reached by Norse settlers in the later ninth century CE, traditionally around 870, though earlier Irish monks may have visited. From Norway the voyage covered a long stretch of open Atlantic, with a stop in the Faroes often described. Settlement continued for several decades and was recorded by later writers. Settlers brought livestock and goods, which implies that the cargo ships were capable of carrying living animals across the ocean, an impressive achievement for the time.
Greenland
Greenland was settled from Iceland, with the saga tradition crediting Erik the Red, who is said to have explored the coast in the 980s after being outlawed. Settlements were established in the south-west, and farming communities lasted for several centuries. The voyage from Iceland was shorter than the earlier one but could be dangerous owing to ice and fog. Greenland was a base for further exploration, and travel there was part of the wider story of Atlantic crossings.
North America
The sagas describe voyages to lands west of Greenland, called Helluland, Markland and Vinland. For a long time these stories were seen as legend, but in 1960 a Norse site was found at L’Anse aux Meadows in Newfoundland, Canada. Archaeologists identified building remains and objects consistent with Norse activity, dated to around the year 1000 CE. The settlement seems to have been small and short-lived, perhaps used as a base for exploring and gathering resources. Its relationship to the Vinland of the sagas is still discussed, as are the exact locations of the lands named in the stories.
Arctic conditions
Sailing in northern waters meant dealing with cold, fog and drifting ice. The Norse hunted walrus and seals in the far north, and their ability to function near the edge of the ice was part of their success. Arctic ice navigation remained a problem for many centuries after, and the Viking experience in Greenland shows both the opportunities and the risks of the region. The decline of the Greenland settlements in the later Middle Ages is often linked with climate and trade changes, though the details are debated.
Why “mastery”?
The word should be used with care. The Norse were skilled and adventurous, and their voyages were remarkable, but they also lost ships and people, and successes were remembered more than failures. The term Norse seafaring skill is useful as a label for a set of practices, not for a flawless record. It also depended on the ships themselves, whose design is described in the articles on the Viking longship and the finds from Gokstad and Oseberg.