A chock is a heavy-duty fitting (metal or wood) mounted on a boat’s deck or rail used to guide mooring lines, anchor rodes, or towing cables, protecting them from chafing against the hull. It acts as a stationary fairlead, holding lines in position to prevent lateral movement, particularly when docking.

Key Aspects of a Chock:
Purpose: Ensures lines are properly directed to cleats and protects expensive teak rails or the hull from wear caused by rubbing lines.

Structure: Usually features two curved jaws that form an opening, which can be mounted on the bulwark or directly on deck.

Types: Common types include open-ended, closed, and Panama chocks.

Alternative Definition: A wedge or block placed under an object (like a boat on a trailer or a wheel) to prevent it from moving.