When referring to a sailing boats course relative to the wind there are some clearly defined terms like "beam-reach", which is exactly perpendicular to the wind. A broader range like "close-reach" is defined as between "beam-reach" and "clause"close-hauled". The latter is what I am not so sure about. Wikipedia defines it as
the craft's course is as close to the wind as allows the sail(s) to generate maximum lift.
That seems to make sense in terms of optimizing speed: If you go more leeward the boat with the tightly trimmed sails will capsize and if you go farther windward you'll get slower.
All texts I read mention "clause"close-hauled" as the "normal" direction when sailing upwind (not explicitly, it's just always the term used). However if your final goal is directly upwind, speed when sailing "clause"close-hauled" competes with a direction closer to your final goal when pointing more windward.
What I would like to know is what exactly is the significance of sailing "clause"close-hauled"? Is it always (well mostly) the ideal course when sailing upwind?