A more thorough explanation:

Definition: A compulsory pilot is a pilot who is required by law to navigate a ship through a particular area. This is usually because the area is difficult to navigate or has dangerous obstacles, and the pilot has specialized knowledge and experience to ensure safe passage.

For example, in some ports and waterways, ships over a certain size or carrying hazardous cargo may be required to have a compulsory pilot on board. The pilot will guide the ship through the area, avoiding hazards and ensuring compliance with local regulations.

The use of compulsory pilots helps to prevent accidents and protect the environment by ensuring that ships are safely navigated through challenging areas. It also helps to ensure that ships comply with local laws and regulations, such as speed limits and environmental protection measures.