Nebula Awards Best Novel (nominee)
The special research vessel 'Alice' was the oddest ship that ever flew the ensign of the U.S. Navy: small, wooden-hulled and sail-powered, she would have been less out of place in the Navy of a hundred years ago--if it weren't for the electrician's nightmare of a christmas tree hanging from her main boom. The purpose of the "christmas tree" was to detect enemy submarines. It wasn't very good at that, but when lightning struck it proved itself highly efficient at.something else. For when the smoke cleared, there off the port bow was a long-ship. Full of Vikings. Throwing things.
Used availability for G C Edmondson's The Ship That Sailed the Time Stream
August 1981 : USA Mass Market Paperback
1965 : USA Mass Market Paperback
July 1971 : UK Mass Market Paperback