How did weather conditions in the Baltic and North seas encourage the use of sails?

The year-round presence of cyclonic storms in the Baltic Sea and North Sea latitudes encouraged the adoption of sails over rowing for small watercraft.1

While early northern vessels were often rowed, the frequent shifts in wind direction characteristic of these regions allowed sailors to navigate in most directions after relatively short waits by sailing with a following wind. This reliance on wind, rather than the absolute dependence on rowing, provided a more economical method for transporting goods. Furthermore, because these boats were less dependent on oarsmen, they could be constructed with a greater freeboard—the distance between the waterline and the upper deck—which helped prevent the vessels from being swamped by the swells of these larger seas.1