The ships will not set out immediately. Their proposed new home is not due to open until 2015. The commitment to move them, which assumes a safe technique will be developed, was required before architectural planning and budgeting for the new museum could begin.

The Oseberg ship's rival for the attention of museumgoers is the more workmanlike Gokstad ship, dating to around 890. Its strakes, ribs and keel have not been analyzed for strength. The third vessel, called Tune, is really only half a ship; but what remains came out of the ground in one piece, held together by the original iron rivets. The most brittle objects are a ceremonial sleigh and a wheeled wagon found in the Oseberg ship.

"We simply don't know what may happen if these things are moved," said Christensen, an archaeologist who recently retired as the ships' curator and has not yet been replaced. "In my opinion, we run the risk of serious damage to both the ships and the artifacts."

Ellingsrud, a mathematician, said Christensen and his colleagues were exaggerating the risk "out of emotion" stemming from their long association with the ships. He acknowledged that they had one more card to play without turning to civil disobedience. Norway's Directorate of Cultural Heritage has the power to declare landmarks untouchable and is evaluating whether the current Viking Ship Museum and its contents should be protected as one monument.

"The point of no return has not been reached yet," Ellingsrud said.