The ColRegs consist of 38 Rules grouped as follows:

• General rules (Rules 1-3)
• Steering and Sailing (Rules 4-19)
• Lights and Shapes (Rules 20-31)
• Sound and Light Signals (Rules 32-37)
• Exceptions (Rule 38) plus Annexes

Purpose of the COLREGS

The COLREGS are a set of international rules designed to prevent collisions at sea. They aim to ensure safe navigation by establishing standards for vessel behavior, signaling, and maneuvering.

Key Rules and Concepts

General Rules:

• Safe Speed: Vessels must maintain a safe speed at all times, considering factors like visibility, traffic density, and sea conditions.
• Proper Lookout: Vessels must maintain a proper lookout by sight and hearing, and by using available aids like radar.
• Risk of Collision: If a risk of collision exists, vessels must take early and substantial action to avoid it.

Steering and Sailing Rules:

• Crossing Situations: Vessels crossing each other should generally give way to the vessel on their starboard side.
• Head-on Situations: Vessels approaching head-on should alter course to starboard.
• Overtaking: Overtaking vessels should keep out of the way of the vessel being overtaken.
• Narrow Channels: Vessels in narrow channels should keep to the starboard side.
• Traffic Separation Schemes: Vessels should follow the designated traffic lanes and avoid impeding the passage of other vessels.

Lights and Shapes:

• Visibility: Vessels must display appropriate lights and shapes to make themselves visible to other vessels.
• Types of Lights: Different types of lights are required for various vessel types and conditions, such as power-driven vessels, sailing vessels, and vessels at anchor.

Sound Signals:

• Fog Signals: Vessels in fog or other conditions of restricted visibility must use sound signals to warn other vessels of their presence.
• Maneuvering Signals: Vessels may use sound signals to indicate their intended maneuvers.

Additional Considerations:

• Exemptions: Certain vessels, such as those under construction or those complying with older regulations, may be granted exemptions from some requirements.
• Verification of Compliance: The International Maritime Organization (IMO) has a system to verify that countries are implementing the COLREGS effectively.

Remember: While these are the core concepts, the COLREGS are a complex set of rules, and mariners should consult the official text for detailed guidance.
Resources; https://www.navcen.uscg.gov/?pageName=NavRulesAmalgamated