A jib sheet is a line (rope) attached to the clew (back corner) of a jib sail, used to control its angle relative to the wind and the boat's centerline. By pulling or easing the sheet, sailors trim the sail for optimal speed and pointing ability, with sheets typically running through fairleads or tracks to a winch on either side of the deck.

Key Details of Jib Sheets:
Function: Controls the tension of the jib's foot and leech, determining the sail's angle of attack and twist.

Routing: Attached to the clew, the sheets run back to adjustable blocks (cars) on tracks, allowing adjustment of the lead angle.

Handling: When tacking, the active ("working") sheet is released, and the lazy sheet on the opposite side is tightened.

Adjustment: Moving the car forward increases tension on the leech (reducing twist), while moving it aft opens the leech (increasing twist).

Safety/Usage: They are essential for balancing the boat's helm and are often used in pairs (one for each side).