@McTag,
The viking long ships were hopeless in deep waters, and were raiders which were rarely risked in the North Sea or the Atlantic. The
knorrir were the great trading ships, and therefore, simply by default, the ships of exploration. The Gokstad ship which was dug up in Norway in the 1880s was a sort of cross between a knorr and a long ship. A replica was built, and was sailed to the "New World," following the same route as that taken by Columbus--and beat his time by quite a bit. It was then sailed to Chicago for the 1893 Columbian Exposition.
The Oseberg ship is also very interesting. It was also a burial mound ship, and is of a type known as a
karv, which is a smaller version of the knorr. It was dug up in the first decade of the 20th century. A replica of this ship was also made, and sailed from Norway (Stavanger?) in the 1930s and made landfall on Newfoundland in just 30 days--a rate of sailing which would be considered respectable by the captains of schooners which regularly sailed from Newfoundland to Ireland and England to trade in those days.
I've got some comments from Farley Mowat's
Westviking on those two ships, and if i get the time, and develop the inclination, i'll copy them to this thread.