Briareus was described in Greek mythology as a fifty-headed and hundred-handed giant, who guarded Cronos on the island of Ogygia. The mythologist, Michael MacRae, interprets this as a reference to Briareus as the captain of a ship with fifty oarsmen[985.180].
Felice Vinci notes that Aristotle had the ‘Pillars of Briareus’ as an earlier name for the Pillars of Heracles(a). Frank Joseph claims that he was also known as Aegeon (Aigaios) whereas Hesiod and Homer have recorded Briareus as the son of Aigaios(b).
(a) Fragment 687 Rose, in Plutarch, Il Voltodella Luna (Adelphi, Milan, 1991) (see ‘c’ below)
(c) http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Plutarch/Moralia/The_Face_in_the_Moon%2a/D.html (see footnote 302, where fragment 678, not 687 is cited))