Lots of good threads on Viking weapons on this site. The largest viking ships was the warships called "Great ship's" used by kings and Earls:
http://www.drakenexpeditionamerica.com/
Several of this ships must have seen action during the numerous large campaigns in England, the Baltic's, France, The Norwegian Civil war, the Norwegian crusade, King Canute's conquest of England.
The Scottish Norwegian war in 1262 - 1266 might have been the last time this type of "Great ship's" set sail on military campaign.