Navigating in the Archipelago Sea area

The area of the medieval site was in active use already in the Middle Ages. However, navigation has always been difficult since there are numerous rocks and small islands in this area and in fact quite a lot of ships have sunken here in the course of history. In addition to the trade routes that led to Finland, the most important northern Baltic trade way of the medieval times, the route from Western and Central Europe to Novgorod and Tallinn, went near the Archipelago Sea.

The earliest written piece of information we have about the navigation routes on the Baltic Sea is from the turn of the 13th and 14th century, only a bit earlier than the time of the wrecking in Nauvo, that is. The written source in question is the King Valdemar’s Cadastral Book (The Codex ex-Holmensis A 41) from the years 1219-1261. This Danish book includes two itineraries (records of routes), one of which gives an account of the sea route from Ribe (in south-western Jutland) to Jerusalem while the other describes the way from Blekinge (in modern southern Sweden) to Tallinn.

The itinerary begins from Utlängan, which is in the west southern end of Blekinge, and follows the eastern coast of Sweden up to the archipelago of Stockholm. From there it turns to the Åland Sea and then follows the northern coast of the Gulf of Finland towards Tallinn. The itinerary gives in fact a collection of itineraries of navigational and travel routes, with alternatives. In all its details the itinerary is difficult, in places impossible, to understand. The route was most likely some 15 kilometres north from the islands of Storskär. It was considerably outer than the main route used from the 16th century on at the latest. The latter route was from Åland to Korpoström and from there either to Turku or towards east to Hanko (via Jungfrusund). According to the Danish itinerary, also a direct route across the northern Baltic Sea from Arholm (off Stockholm) to Hanko could be used in case there was a good western wind.

Permanent settlement in the archipelago had its influence on navigation routes. When settlement became more established, the route that followed the northern coast of the Gulf of Finland likely moved from the outer archipelago to the inner archipelago. Now that there were people living in the archipelago, passers-by could use local pilots to navigate in the narrow waters.

A trade route from Stockholm to Tallinn, as described in a Danish cadastral book. The Nauvo wreck site is marked with a cross. Map: Mikko Rautala.