[ Sailing distances in doegr as outlined in Icelandic sources ]

Sailing distances in doegr as outlined in Icelandic sources, Vis-ŕ-Vis Graphics,

To decode the descriptions in the Sagas we need to understand how the Norse gave directions and how they navigated. To determine where Vinland is, we need to know how far their longboats could go in a day, week or month and what time of the year they traveled.

It is astounding, considering their amazing feats of navigation, that the Vikings had no instruments for navigation except perhaps some simple device to measure the position of the sun and the Polar star above the horizon. This would give a navigator a rough determination of his position north-south. During much of the sailing season the Polar star would not have been of much as there is almost perpetual daylight from May to September on northern latitudes. Otherwise sailing depended on dead reckoning, observing the swell of the water, prevailing winds, birds and bird migrations, and keeping track of time passed.

Viking sailors could not determine longitude, that is their position east-west. In order to find the longitude one must know the exact time that has elapsed since one left a specific point of reference. This was simply not possible until the invention of accurate clocks in the early 18th century. On land it was easier as there one could observe the position of the sun on the horizon in relation to a land mark and they knew from experience how it changed with the seasons. On the sea in a constantly moving ship and no land marks, navigators would have had only a rough idea of the time.

The sagas speak of “sun stones,” a rare tool for observing the position of the sun even when the sun is hidden by clouds. The “sun stones” are still a mystery to us moderns. Some scholars have concluded that this would have been a piece of feldspar which polarizes the light and shows the sun. Others have pointed out that this is possible only when the sky is only partially clouded, so in most cases such a ‘sunstone’ would be useless.

A small wooden disk with notches along the edge found at a farm in Greenland is believed by some to be an instrument for measuring the angle of the sun and moon. Others believe that this disk is a calendar wheel used to keep track of church holidays.

Distances at sea were expressed in doegr sigling. This does not mean ‘a day of sailing,’ as it is often translated. A day was dagr. Doegr means a period of less than 24 hours. When sailing along the coast, where shoals could be present, travelling preferably took place during daylight hours. On the open sea, however, sailing was continuous as was the daylight in the summer, and there doegr came to mean a 24-hour period after all.

Speed depended on the weather and varied from voyage to voyage as well as from one ship to another. The information we have on the speed a large Viking cargo ship could achieve comes from two sources. One is from experiments with replica ships. The other is from statements in the sagas. Under favourable wind and weather conditions the replica of a small Viking cargo ship could reach a speed of up to 15 knots. One knot is 1.852 km per hour, which makes the speed in this case 27.8 km per hour. The average speed was only 4 to 5 knots, that is 7.4 to 9.3 km per hour. That would mean that in a 24-hour period, under favourable conditions, a ship could cover approximately 178 to 222 km. Unlike later sailing ships, the square sail did not lend itself to tacking more than 20° , so if the winds were completely against them, the best solution was to “reef”, or take down, the sail. Tacking slowed them down to as little as 1 to 2 knots. One thing often forgotten in the determination of the speed of Viking ships is that there could also be periods of no wind, when the speed slowed to nothing. This was the experience of the crew of the replica ship Snorri that sailed from Greenland to Newfoundland in 1998. The crew tried rowing but cargo ships, unlike warships, were not meant for rowing, so the crew could not move the ship more than a km or so in a day, even with the most intensive efforts.

For the Vikings, the navigation season was limited to the summer months because their ships could not handle the winter storms. The Saga of the Gotlanders states that sailing on the Baltic seas should take place between May 1 and November 1. The King’s Mirror, an educational treatise written about 1250, recommended that sailing to or from Greenland take place during the height of summer, that is July and August, and that no voyages should take place after September. The Icelandic and Greenland season would have been shorter than any other because of the presence of dangerous sea ice outside the coasts although around AD 1000 there was less ice than in earlier and later centuries. Even so, during most years it was probably not possible to leave Greenland until June and it would have been prudent to be back by mid-September.

The Norse concept of precision in time-keeping, compass directions, speed, consistency, and the need of instruments was totally different from ours. Exactitude in time, direction, and speed was non-existent. Rough ideas sufficed. Was it morning, evening or midday, winter or summer? For navigation, where it was impossible to maintain a straight course, one needed only an approximate idea of direction. The instructions in The Book of Settlements how to get to Greenland from Norway would probably not inspire confidence in a modern sailor.

Landmarks were more important. A typical description of a sailing route was told by the Norwegian chieftain Ottar in The Voyages of Ottar [Othere].


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