Near the city of Roskilde in Denmark, a settlement since Viking times, groups learn how to sail boats designed more than a millennium ago, on day courses run by the Roskilde Viking Ship Museum. It has built exact copies of ancient ships recovered from the surrounding waters.
Centuries ago the sight of these vessels would have struck fear on British shores, but there will be a very different effect next month when one of these warships sails up the Thames into London's St Katharine Docks, during the Olympics for a series of Norse-themed events, which begin on 27 July.
"They're perfectly constructed for the North Atlantic waves," says Søren who, with his big red beard and bright blue eyes, lives up to my notion of a Viking skipper.
The museum's ship builders use traditional methods and even specify which trees they want felled when searching for their material. The beauty of the boats and vibrancy in the boatyard seems to awaken a seafaring instinct in our group of novice sailors.
Once under sail, we feel how sturdy and well-crafted these vessels are. "They're designed to sit on top of the water rather than in it," Søren explains, "which makes for a very different sailing experience."
Handling a longboat is not the same as with a modern yacht. The large sail requires a unique tacking manoeuvre, very similar to a car's three-point turn. Coated in horse fat, the sail becomes quite unpleasant on warm days. "After a hot day on the water," says Søren almost gleefully, "getting a seat on the train isn't a problem."
Roskilde was a perfect site for a Viking settlement. Its calm fjord hid some of their most important technology. The Norse were predominantly traders. Skilled navigators, they explored as far east as Istanbul, where they sourced sail material as the Silk Road emerged from Asia. Today, only 20 minutes from Copenhagen, it's a popular marina for watersport enthusiasts and the pedestrianised centre is dotted with restaurants and bars.
As if the town needed any more Viking credentials, some of Beowulf's adventures are thought to have taken place in the region, in the nearby village of Lejre. And the cathedral, its elegant twin spires visible from all over Roskilde, is the burial site for Denmark's monarchy. Danish royals have been interred here as far back as Harald Bluetooth, the first ruler to unite the state of Denmark in the 10th century.
With the British Museum's major Viking exhibition planned for 2014 and the Thames-side Norse events planned for the Olympics, including concerts and Danish food and drink to sample, the coming months are bound to rebalance the reputation of this much-maligned Middle Age culture.
Crowds gather on the wharfs to watch as we row back into the harbour to finish the day, the oars stroking in unison. As we lower the heavy sail, my hands blackened from the freshly tarred rope, I wonder whether getting a seat on the busy 20-minute train back to Copenhagen might not be a problem after all.
• The Roskilde Viking Ship Museum (+45 46 300253,vikingeskibsmuseet.dk) runs Viking ship sailing courses in early and late summer, costing DKK675 (about £70). The Danish Tourist Board (visitdenmark.com) provided the trip. EasyJet (easyjet.com) flies to Copenhagen from Gatwick, Stansted and Bristol from £36 return. Doubles at Hotel 27 in Copenhagen (hotel27.dk) start at £127, and doubles at Hotel Prindsen (prindsen.dk) in Roskilde itself at £105.