Possible Clues:

• Canaries' setting
• Duke leaving country in Greek liner might cross it
• Cat-o'-nine-tails remarkably noiseless in the ocean
• Neighbor of Ventnor on a Monopoly board
• Sight from Cape Hatteras
• Canaries are found there
• Ocean from Arctic to Antarctic
• See 43-Across
• Cat-o'-nine-tails remarkably noise-less in ocean
• Western ocean.