In a jibe, the the stern of the boat is passed through the wind. both the mainsail and the jib have to be adjusted. Ideally, this maneuver is performed by three sailors, a helmsman and one working each sail. The mainsail is first centered at the beginning of the turn. As the stern passes through the wind, the mainsail is let out. The jib is adjusted by taking the sail's working sheet off the leeward winch and placing the new working sheet on the opposite winch, trimming the sail.