Steering a ship in such way that it maintains the same direction relative to the wind. Similar to "hold your course," except that if the wind's direction shifts, you shift with it. (In other words, steering by the wind rather than the compass.)
messy; in disarray—similar to another, more common, Briticism: “At sixies and sevens”.
Captain: “This deck is still all ahoo. If you people do not have it squared it away prior to the departure of the next launch, every one of you will remain on ship, having forfeited all shore leave .”