Function: 

Mooring chocks guide and protect mooring lines as they pass from the vessel to the dock or another vessel. They help distribute the load evenly and prevent the lines from chafing or sustaining damage.

Types:

Closed Chock: Has a completely enclosed design that prevents the line from slipping out.

Open Chock: Has an open design, making it easier to lay the line in but requiring more attention to ensure the line stays in place.

Materials: 

Typically made from durable materials like cast steel, stainless steel, or cast iron to withstand harsh marine environments and the significant forces exerted by mooring lines.

Placement: 

Installed on the deck or bulwark of a vessel at strategic points to ensure optimal line handling and load distribution. Proper placement is crucial for the safety and stability of the moored vessel.

Maintenance: 

Regular inspection and maintenance are necessary to ensure the mooring chocks remain in good condition and function correctly. This includes checking for corrosion, wear, and structural integrity.