A sailboat spreader is a strut extending from the mast, perpendicular or angled slightly aft, used to push shrouds (standing rigging) outward. This increases the rigging angle, providing lateral support, reducing mast compression, and breaking up unsupported mast length, allowing for a lighter, thinner mast.

Function: Spreader tips hold the upper shrouds, enhancing mast stability. They are crucial for controlling mast bend and rake.

Materials: Typically made of aluminum, wood (spruce), or carbon fiber for racing rigs.

Types:
Fixed: Rigidly attached, common on cruisers.

Swinging: Pivoted at the mast, often used on racing boats for better tension control.

Components: Inboard ends attach to the mast via a mast bracket (sometimes called a spreader box or base). Outboard ends feature specialized spreader tips or terminals that hold the shroud securely and often protect the sail from chafe.

Configuration: Many modern boats have swept-back spreaders that force the mast into a slight bend. Multi-spreader rigs are standard on tall masts to provide support higher up.