Single-line reefing is a method used to reduce the area of a sail by folding or rolling part of it down. This technique allows sailors to adjust the sail size quickly and efficiently, especially in changing wind conditions. It simplifies the process by using a single line to control the reefing, making it easier for one person to manage. This system is commonly found on various types of sailing vessels, including yachts and catamarans. By employing single-line reefing, sailors can maintain better control of their boat and enhance safety while sailing in stronger winds.