Answer:
With no access to modern navigation instruments, Vikings relied on birds, ... They understood how to link their travel stories and sensory ... They knew from experience what time of the season was best for each of the various routes. ... Recognition and respect:
Explanation:
The sun, the moon and the stars provided the Vikings with a decent understanding of which direction to travel.
The Vikings sometimes spent weeks waiting for optimal weather conditions before they set out to sea, so that the journey should be as short and safe as possible.
They knew from experience what time of the season was best for each of the various routes.
Source: Anton Englert
But in fog and cloudy weather these celestial bodies are not visible, and on long stretches, a deviation of only a few degrees from the planned route can mean that you end up completely missing your intended destination.
For this reason, the Vikings also kept an eye on objects on land when they sailed along the coasts. A rock with a particular shape, for instance, or a hilltop, could provide some clues to where they were.
Chants and rhymes showed the way
Since there were neither nautical charts nor any written descriptions back then, the Vikings’ travelogues consisted of narratives and rhymes.
An example of these travelogues can be found the medieval Norse manuscript ’Hauksbók’:
Trees, islands, hills, buildings, etc. were often given place names based on their special characteristics.
These names helped the Vikings navigate their way to their destination.
"From Hernam [present-day Hennø near Bergen] in Norway, head due west towards Hvarf in Greenland, and you will have sailed north of Hjaltland [the Shetland Islands}, so that you just glimpse it in clear weather, but south of the Faroe Islands, so that the sea [the horizon] is right in between the distant mountains, and thus also south of Iceland.”
In other words: they sailed from Hennø in Norway, heading due west towards Greenland, between Shetland and the Faroes and south of Iceland.
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.
If for instance they had long since passed the Faroes and saw a particular terrestrial bird, this could be a sign that they were near Iceland.
Much of what we know about the Viking’s navigation is based on hypotheses and trials.
Viking ship researcher Morten Ravn says that researchers also use experimental archaeology as a supplement to archaeological finds and written sources from medieval times. Test voyages are an example of experimental archaeology.
Source: Morten Ravn
Whales usually stay close to currents where fish can be found. The Vikings knew where whales typically resided, and this knowledge helped them figure out where they were in relation to e.g. Iceland. Hope this helps you! Ask me anything if you have any quistions!