An old sailing ship expression used in the days of square-riggers rigged with yards. To lay the head-yards abox was to lay them square to the foremast in order to heave to. This brought the ship more under command if it was subsequently required to wear or to stay the vessel. But to brace abox was to brace the head-yards flat aback to the wind, not square to the mast, in order to ensure that the wind acted on the sails so that the bows of the ship cast the required way.
Subjects: Maritime History.