Answers.com explains that this expression was believed to have originated in the 15th century to describe navigation of ships through straits where it “…took experience and a steady hand to make safe passage…” There are many straits where the passage is difficult and perilous, and an error results in shipwreck. The expression evolved to mean any difficult or perilous situation, according to Mr. Mark Frees, professor of naval history. There is apparently a London rock band that adopted the name, although I don’t know I would want to listen to a band named after an expression meaning difficult or perilous.