The Viking Navigations

   As we learned from Pico and Alberti, we can understand about order of nature by observing it in detail and we can use it as our guid. Many centuries ago, Vikings had accomplished it very well and it amazingly moved them forward from their rivals. They navigated the world, with no access to modern navigation instruments, Vikings relied on birds, whales, celestial bodies, chants and rhymes to navigate the seas and discover new land. 
   They understood how to link their travel stories and sensory impressions with observations of wind, weather, wildlife and solar time. This enabled them to figure out which way to go.  
   Experience helped Vikings understand nature.The Vikings had an understanding of nature, since they lived in the wild. But their observations didn’t lead to any scientific data that they could use to construct precision tools.
   Birds and whales served as navigation marks. When out sailing, the Vikings used wildlife as landmarks. Birds were particularly helpful, since some birds only flew a certain distance away from land.

   

   However, the most important reason behind hundreds of succesfull raids was the navigation technology they've discovered. They used a sun compass, but mind blowingly which can be used without sun as well.

Here are the tools they used and the scene that, they are explained by our king Ragnar Lothbrok. 

https://www.youtube.com/watch?v=sl-XdT_ad4c

The Sun Board

The sun shadow board was used at noon to double check whether the ship was on the correct course or not. It was placed in a bowl of water to keep it level and the gnomen, the pin in the center of the board, marked the shadow of the noon sun. Circles marked on the board gave the sailors an area in which they could travel and still remain within their desired latitude. If the shadow of the noon sun extended beyond the circle, they knew they had traveled too far north. If the shadow was inside the line, they were too far south. The sun shadow board’s midday measurement helped the Vikings make course corrections each noon, but was of no use to the sailors in cloudy or foggy weather.

The Sun Stone

The sun stone was used on the days when fog or clouds obscured the sun. The stone, a mineral called Icelandic spar, would change color as it was turned in the light. A certain color would indicate the position of the sun through the fog or clouds but could only be used when there was at least a sliver of blue sky.

Here is the publish for detailed explanation of navigation tools used by Vikings and working principles of them.

http://rspa.royalsocietypublishing.org/content/470/2166/20130787