A Mighty Ship was the Gundremar, by Kathleen Davis. Full lyrics in the DT (under "A"). Final stanza:

A ghostly ship is the Gundremar
Ever sailing, ever sailing,
O'er winter skies she adventures far
Northward hailing, northward hailing.
No shadow falls on the silver night
As down the moonlit way she takes her flight
Ever sailing, ever sailing.