Points of sail

The points of sail. A. In Irons (into the wind) B. Close Hauled C. Beam Reach D. Broad Reach E. Running (not shown: Close Reach, between Close Haul and Beam Reach)

The point of sail describes a sailing boat's course in relation to the wind direction.
No sailboat can sail directly into the wind (known as being "in irons"), and for a given boat there is a minimum angle that it can sail relative to the wind; attempting to sail closer than that leads to the sails luffing and the boat will slow down and stop. This "no-go zone" (shown shaded in accompanying figure) is about 45° either side of the true wind for a modern sloop.
There are 5 main points of sail. In order from the edge of the no-go zone (or "irons") to directly downwind they are:

• close haul (the minimum angle to the wind that the boat and its rig can manage - typically about 45° )
• close reach (between close hauled and a beam reach)
• beam reach (approximately 90° to the wind)
• broad reach (between a beam reach and running)
• running (close to directly downwind)

The sail trim on a boat is relative to the point of sail one is on: on a beam reach sails are mostly let out, on a run sails are all the way out, and close hauled sails are pulled in very tightly. Two main skills of sailing are trimming the sails correctly for the direction and strength of the wind, and maintaining a course relative to the wind that suits the sails once trimmed.