To head the boat in a specifIc direction. You can stand across a bay, or stand into it, and in each of those examples the implication is one of positive motion in a positive direction. But when a vessel Stands off she may lie hove-to or sail around aimlessly, waiting at some distance offshore. And when she Stands on and off, she first stands (ie. sails) towards the shore, and then away from it, but only with the intention of killing time and not with the desire to get anywhere.