On a sailboat, what is the function of the lines known as 'sheets'?

The function of the lines known as 'sheets' on a sailboat is to control the orientation of the sails. Sheets are ropes or lines that help adjust the angle of the sails in relation to the wind. By pulling or loosening the sheets, a sailor can trim the sails to maximize their efficiency and adjust the boat's speed and direction in various wind conditions.

This is critical for the performance of the sailboat, as properly trimmed sails can significantly enhance sailing effectiveness, allowing for better maneuverability and a more comfortable ride. In contrast, the other options refer to different components and functions of a sailboat, such as raising the mast, securing the rudder, or balancing the vessel, which do not involve the direct control of sails' trim.