Clew

The lower aft corner of a sail, where the foot and leech meet, and is often equipped with a grommet or cringle for attaching control lines such as the sheet.

The clew is a critical component of a sail’s geometry and functionality on a sailing vessel. It is one of the three corners of a triangular sail, specifically the corner located at the aft (rear) end of the sail’s foot. The clew serves as the attachment point for the sail’s sheet, which is the line used to control the angle of the sail relative to the wind. This positioning allows sailors to adjust the sail’s trim, thereby optimising the vessel’s performance and manoeuvrability.

In traditional square sails, there are two clews, one at each lower corner of the sail, as these sails are typically rectangular. In contrast, fore-and-aft sails, such as jibs or mainsails, have a single clew. The clew is reinforced to handle the significant loads exerted by the sheet, often featuring a grommet, cringle, or other robust fitting. This reinforcement ensures durability and prevents tearing under strain.

The clew’s position and tension are vital for shaping the sail and maintaining its efficiency. For example, adjusting the sheet attached to the clew can alter the sail’s angle of attack to the wind, influencing speed and direction. Proper handling of the clew and its associated rigging is essential for safe and effective sailing, making it a fundamental concept for anyone operating a sailing vessel.