Pontoppidan, in his Natural History of Norway, speaks of sea serpents 600 feet long. The great sea serpent was said to have been seen off the coast of Norway in 1819, 1822, 1837. Hans Egede affirms that it was seen on the coast of Greenland in 1734. In 1815, 1817, 1819, 1833, and in 1869, it made its appearance near Boston. In 1841 it was “seen” by the crew of Her Majesty's frigate Daedalus, in the South Atlantic Ocean. In 1875 it was seen by the crew of the barque Pauline. Girth, nine feet.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894