How did seamen in Viking times dare sail without GPS?

Published 31th Jul 2007

To sail an open boat on the high seas is not without risk. It is clear that the crew of the Sea Stallion is employing modern safety equipment to avoid or mitigate the consequences of a possible accident. But how did Viking-Age seamen manage without the technical security that we take for granted today in the form of weather forecasts, sea charts, high-precision navigational instruments, life jackets, survival suits, life-rafts, communications with land, and access to an air-sea rescue service? The thoughts below are based on my own experiences, see footnote.


Good seamanship and staying power

A master key to safe sailing is to be able to look after oneself in all situations. A Viking-Age ship is built of wood and easier to repair than modern technically complicated boats. With the aid of fantasy and experience the skipper can guard against eventual narrow escapes by having a well maintained ship whose weak points are known and by taking with him tools and material sufficient for being able to do most of the necessary repairs at sea.


A practised crew that can work even when seasick and lacking sleep is another safety factor. One soon learns to eat and drink again every time after one has had to throw up. It is more difficult to get sufficient sleep without the protection of a tent, especially the first day before one is tired enough to be able to sleep in spite of the cold, the wet, the movement, the noise, and the hard resting-place. Many layers of woollen clothing (see Roar Heini Olsen’s comments) are a necessity. A small personal tarpaulin (maybe skin in the Viking-Age) gives good protection against the two great thieves of warmth, wind and rain, and creates the badly needed illusion of having “one’s own room” in a ship where there is otherwise no room for private life. The traditional watch system 1:1 is exhausting when one has to sleep more or less between the feet of those who are working. If there are a lot of people on board, a stand-by system can be employed when conditions are calm and this gives some possibility for rest even for those who are on duty.


Plenty of time

Another key to sailing safely is to have good time and no fixed date of arrival. It has to be possible to lie to and wait for perhaps several weeks for a favourable wind (see Erik Andersen’s comments). Just as important, however, is to exploit the favourable wind. It may come at a time that is inconvenient for the other plans the crew has, or perhaps in the middle of the night. A square-sailed boat without a motor, however, has to to exploit every opportunity to use a favourable wind. One never knows when next a favourable wind will arise and, depending on the type of ship, it can take approximately six times longer to beat against the wind than to sail with the wind astern. Tacking also involves more wear and tear on the ship and crew, which in turn is a risk one is unwilling to take.

Bringing with one substantial rations of food and water makes it possible to get through unpropitious situations, such as an unexpected headwind or an error in navigation, without becoming stressed (2-2.5 litres of water per dag is usually enough in cool weather, as is most often the case in the North Sea, providing that one, for example, uses salt water for boiling potatoes). An open attitude to the fact that a planned short trip can turn out to be very long gives one a humility which counteracts the taking of risks.


The average – a key to Viking-Age navigation?

We do not know whether Viking-Age navigators had help from some simple instruments, such as the sun compass, or whether they managed with the help of merely their own observations of nature. Without sea charts and the magnetic compass navigation becomes imprecise. Practical experiments, however, have shown that it can have been possible to sail completely without instruments with an average deviation from the desired course of no more that 10-11 degrees, provided that one could see the sun from time to time. (Sea charts with the navigation information removed are employed in these experiments for passing on the estimated position to the next man at the helm). Such precision is sufficient even in misty weather to find the North Atlantic island that is the goal so that one can subsequently sail further along the coast to the harbour required. Since the deviations in course are often made both to starboard and to port, depending among other things on how the helmsman assesses the position of the sun and its relation to the boat, the actual currents in the area, drift, etc., the total error in the course on one voyage can be less than 10 degrees. The same applies to the assessment of the distance sailed, which is rarely more than 5% in error on average, provided that one has sailed for at least 24 hours. If one does not catch sight of the sun for long periods, however, it can be difficult to navigate. Then it can be sensible to lie to, instead of continuing to sail further on an uncertain course.



Present-day sailors acquire a lot of information from aids that they can buy, which sometimes takes the place of their own senses and competence. But without a clock one is forced to take note of where the sun is; without the weather report, one becomes observant of changes in the weather; without GPS, one notices where the birds are flying and notes the direction of the groundswell; without sea charts, one listens to the oldest man on board who has memorized all the fiords and significant mountain tops that he has seen on his voyages. By paying attention and using experience, one can obtain information, some of it admittedly imprecise or incomplete but even so in many cases sufficient to sail quite safely. A skipper who relies blindly on his GPS-position will perhaps hardly look out of the window of his wheel house but risks over-shooting his goal, while a skipper who knows that his position is uncertain will sail carefully and listen for the breakers many hours before he thinks he is about to reach land.


In summary it can be said that the absence of modern technical security could at least in part be compensated for in the Viking Age by good seamanship and experience, as well as a far-sighted, attentive and flexible attitude.



Lena Lisdotter Börjesson has among other things sailed about 10,000 sea miles with open square-sailed boats in north European waters, sailed 13 times across the North Sea and completed 2,000 sea miles experimental sailing using Viking-Age navigational methods. 

Created by Lena Lisdotter Börjesson, sailing instructor, Fosen Folk High School, Norway