Named after Harald Hårfagre, the king who unified Norway in the 10th century, the ship's Swedish captain Björn Ahlander was originally supposed to have ordered the great dragon vessel to weigh anchor from Avaldsnes in Norway's Haugesund on Sunday, but the departure was delayed by bad weather.
And time is of the essence. Following in the historical tailwind of Leif Eriksson, the Viking thought to have discovered America centuries before Christopher Columbus, the ship has a long journey ahead, taking a route via Iceland, Greenland and Newfoundland before it finally drops anchor in the United States.
"We've got one month because the only gap, if you don't want to battle low pressure and harsh winds, is May. That's your chance to make it across," Ahlander told the Swedish news agency TT on Monday.
The Dragon's head Ceremony! https://t.co/9WeC1fYwf3- DrakenHaraldHårfagre (@drakenhh) April 25, 2016
The Viking ship will be accompanied by another boat, on standby to rescue the 33-strong crew on board if things go awry during the voyage.
"We're going across the world's most dangerous waters, including around the southern tip of Greenland, with a lot of ice and cold. We have no protection, it's an open ship. If something happens, it's extremely serious," said Ahlander.
Harald Hårfagre is equipped with modern navigational tools, but also historical aids such as log lines and magnetic and solar compasses.
"We are very conscious of the fact that everything can be knocked out, electronics and salt water are not the best of friends. So we've now got navigational methods borrowed from the Vikings, from the 18th century and from 2016," said Ahlander.
An impressive 35 metres long, eight metres wide and with a mast height of 24 metres, Harald Hårfagre is the world's biggest longship built in modern times. Sponsored by Norwegian businessman Sigurd Aase, it was completed in 2012.
The ship's route (dates not exact)
May 1st: Reykjavik, Iceland
May 16th: Qaqortoq, Greenland
June 1st: St Antony, Newfoundland, Canada
June 15th: Quebec City, Canada
July 1st: Toronto, Ontario, Canada
July 8th: Fairport Harbor, Ohio, US
July 14th: Bay City, Michigan, US
July 27th: Chicago, Illinois, US
August 5th: Green Bay, Wisconsin, US
August 18th: Duluth, Minnesota, US
September 5th: Oswego, NY Canals, New York
September 15th: New York City, US
October: Mystic Seaport, Connectictut, US