It was never intended to be a feature Jonny - this glitch just happens every once in a while where you can 'sail' though an island (and only another can doc for you).
I do some great screenies somewhere around here of one night we had the glitch... one in paticular where I'm shooting Lighting at the town buildings and its going off above them
Almost looked like a storm was rollin' in... I'll try to dig them up at some point and post them in the Screenshots folder...
Nice shot there Nat