A short distance south from Frederikssund, the Roskilde Fjord narrows considerably at a location known as Skuldelev. At this point in the fjord, there are 3 channels capable of north-south navigation, the western channel being the most direct access from the North Sea to the town of Roskilde that sits at the southern end of the fjord.
To better appreciate why we drove to Roskilde for the day, a little history of the Viking Age might be helpful at this point:
By the year 800 A.D., the Kings of Denmark dominated most of Scandinavia, including all of modern-day Denmark, most of southern Sweden and Norway, and part of northern Germany; but, there was considerable infighting within the royal family because any male descendent of the King had a claim to the throne upon the King’s death. This state of affairs is what led, in large part, to the early Viking raids along the coasts of the English Channel and throughout what is today known as the United Kingdom, as various claimants to the throne raised bands of marauders in order to steal sufficient riches from those lands in order to fund their plans to capture the Crown back in Denmark.
By the latter half of the 10th Century A.D., however, the Danish Kingdom was unified by King Harald Bluetooth (958-987 A.D.) and much of the prior infighting and foreign raiding faded away. During his reign, Harald Bluetooth converted to Christianity and established his capital city, Roskilde, at the bottom of the Roskilde Fjord where, in 980 A.D., he built the first Catholic church in Zeeland.
Shortly after 1000 A.D., in an effort to expand the Danish empire, the Vikings again raided the English coast; this time, however, with the goal of conquest. Though temporarily successful, the Danish Vikings were ultimately defeated in England in 1066 A.D., following which, they lost their grip not only on those lands, but also on their domains in Norway and Sweden.
Toward the end of Age of the Vikings – and following their defeat in England – the Danes became less interested in conquest and more concerned about being invaded themselves. So, sometime after 1066, in an effort to better defend their capital city by forcing potential invaders to use the winding and more easily defended channel to the east at Skuldelev, they scuttled and sank 5 boats in the westernmost channel there.
As it turned out, no invasion down Roskilde Fjord ever materialized.
In the 1950s, amateur divers exploring the area uncovered the bow stem of one of these boats and in 1962, the Danish government undertook a concerted effort to retrieve the wrecks. Sheet pilings were driven into the seabed to form a perimeter so that the area could be pumped dry and the remaining timbers inventoried and excavated. After 25 years of piecing the boats back together, the 5 boats are now on display in the Vikingeskibene i Roskilde, the Viking Ship Museum.

The most complete of the 5 recovered boats is the smaller trading vessel known as Skuldelev #3. Built of oak, it is 46 feet in length with a beam of 11 feet. Like all the other boats recovered at Skuldelev, it is of lapstrake construction, that is, the planking overlaps at the edges, fastened by iron nails and wooden pegs.

Although it had no keel or centerboard and a draft of less than 3 feet, it was primarily a sailing ship, crewed by 5 to 6 men, with an average speed of 4 knots, but capable of reaching a maximum speed of 8 knots in the right conditions.
We were fascinated by the stem (the part of the keelson that extends upward at the bow), the original of which you can see on the far wall in this picture (I believe that this was the first artifact recovered at Skuldelev):

The entire stem was hand carved out of a solid piece of wood with feathered notches so that the planks could be attached seamlessly at the bow.
It’s amazing when you think about the craftsmanship involved in making a boat like this with hand tools over 1,000 years ago. In those days, the best the native American Indians were doing was hollowing out a tree trunk to make a dugout canoe!