" ALOOF! An old expression meaning 'Keep your luff', or sail as close to the wind as possible. Sometimes, in old books of voyages, written as 'ALUFFE'. The expression was most often used when a ship was sailing along a lee shore, the order to 'keep aloof' meaning to keep the ship's head nearer to the wing to prevent her being driven closer to the shore. "

I never saw this before, and can't imagine how it acquired its usual meaning.Incidentally, the "wing" in last sentence of definition must be a typo for "wind".