A centerboard is a retractable, pivoted fin located in a slot (centerboard trunk) within a sailboat’s hull, designed to provide lateral resistance, minimize sideways drift (leeway), and improve upwind performance. It can be raised for shallow water or reduced drag downwind and lowered for stability.

Key Characteristics and Components:
Pivot Function: Unlike a vertical daggerboard, a centerboard typically hinges at the forward end, allowing it to swing up and down into the trunk.

Shape: It features a symmetric foil shape designed for equal performance on both tacks.

Material: Often constructed from heavy materials like steel or lead, or molded fiberglass/plastic.

Controls: Operated via a line (pennant) to raise and lower the board from the cockpit.

Recovery: Acts as a stabilizer to stand on for righting a capsized dinghy.

Key Benefits:
Shallow Draft: Allows sailing in shallow water and easy beaching.

Upwind Performance: Deep, locked-down position allows for better windward efficiency.

Performance Tuning: Can be partially raised to reduce drag, enhancing speed in downwind conditions.