The 8.25-ton ship was built using replicas of Viking era tools, "5,250 cubic feat of oak and 7,000 hand-forged iron rivets."
"They must have been incredibly tough to do what they did," said 24-year-old crew member Triona Nicholl, an archaeologist from Dublin. "We all have waterproof gear. We have radios and life jackets and all the stuff. They must have been hardier people."