It is worth remembering that the Norse did not reach America through a direct crossing starting in Norway and then ending in Canada. Rather, Leif Erikson's voyage to North America in 1000 AD was the culmination of a gradual expansion across the North Atlantic, using a set of stepping stones that shortened each step of the water - first to the Faroe Islands, then Iceland, then Greenland, and then finally from Greenland to North America. THe feat of Leif Erikson (according to the Sagas) was the crossing from Greenland to mainland North America, which is arguably not the most challenging part of the crossing.

The longest stretch was the one from Iceland to Greenland (which was later frequently replaced with a direct crossing from Norway, which would probably be the longest stretch of open water regularly traversed by the Norse). This crossing took three to four weeks on average, which is a long trip without seeing land, but quite doable, and much shorter than the distances crossed by European ships in the Age of Exploration. The viking ships designed for trade had relatively large holds and could hold enough supplies for such a crossing. Running out of supplies was not the main concern on these voyages, rather stormy weather and ice were a bigger problem.

Therefore, it is worth reminding that at no point did any voyage actually travel from Europe directly to North America. They sailed from Europe to Greenland, and then other ships sailed from Greenland to Canada and beyond, a much shorter trip. These trips were so doable that they likely became an annual event for centuries after the establishment of the Norse colony in Greenland, as we have reports from as late as 1346 stating Greenalnd ships sailed to Markland to seek out lumber.