The song you know from the BeeGees version is the unofficial Manx National Anthem ("Ellan Vannin" -note the spelling - being the name of the Island in Manx) and is a Victorian ballad. The one about the loss of the ferry is a totally different song - I remember hearing the Spinners singing it at the Philharmonic Hall in the 60s.

As I now live on the Isle of Man I hear both of them quite often at sessions.