Reefing
Reefing is the means of reducing the area of a sail, usually by folding or rolling one edge of the canvas in on itself. The converse operation, removing the reef, is called "shaking it out." Reefing improves the performance of sailing vessels in strong winds, and is the primary safety precaution in rough weather. Reefing sails improves vessel stability and minimizes the risk of damage to the sail or other gear. Proper skills in and equipment for reefing are crucial to averting the dangers of capsizing or broaching in heavy weather.