A sailor has endured much without fear -- until the night twelve ghosts board his ship and take stations "as if [they] had a right." They disappear as the ship passes a lighthouse. The singer is sure they are sailors drowned in a collision with his ship
Gordon Bok reports, "The story I heard was that the schooner _Haskell_, out of Gloucester, was anchored near George's [Bank] when a sudden gale parted her ground tackle and she went charging, bare-poled, down through the fleet. She cut the schooner _Johnston_ almost in two, killing all her men. On every voyage thereafter, a crew would appear on her deck at night and go through the motions of fishing. After a few trips, no crew would even sign on her, and she rotted at the wharf."
Creighton-SNewBrunswick adds more details: On March 7, 1866, the new _Charles Haskell_ rammed the _Andrew Jackson_, inspiring this song; the _Haskell_ later became known as "the ghost ship."
Some of this may be folklore; after all, we hear a lot of ghost stories about ships sunk by ramming. For example, a story very much like this took place twenty years *after* Marcy's text was published: On June 22, 1893, HMS _Camperdown_, in a confused practice maneuver involving an admiral showing off, rammed HMS _Victoria_, causing the latter to sink with the loss of 358 men including the admiral. _Camperdown_ survived, but was put into reserve roles not long after, and was broken up in 1911 although she was only 22 years old.
And there is a ghost associated with the story: According to Peter Underwood's _Gazetteer of British, Scottish & Irish Ghosts_, p. 135, shortly after the _Victoria_ sank, the ghost of the admiral aboard, George Tryon, was seen at the home of Lady Tryon in London. - RBW