Sails are large pieces of fabric used on boats and ships to catch the wind and propel them forward. They are typically made from materials like cotton, polyester, or nylon, and come in various shapes and sizes depending on the type of vessel. Sails are attached to masts and rigging, allowing sailors to adjust their position to harness the wind effectively. When the wind blows against the sails, it creates lift, similar to how an airplane wing works. This lift helps move the boat in the desired direction. Different types of sails, such as main sails, jibs, and spinnakers, serve specific purposes and enhance a vessel's performance on the water.