To maintain maritime safety, the International Maritime Organization (IMO) and national maritime authorities have implemented stringent standards for color and visibility of marine navigation lights. These regulations are crucial to ensure that navigation lights perform effectively under diverse maritime conditions, thus preventing collisions, adhering to maritime laws, and communicating vessel status and type.

Importance of Marine Navigation Lights

Collision Prevention: Navigation lights help vessels indicate their presence and direction of movement, allowing nearby vessels to make informed decisions to avoid collisions.

Compliance with Maritime Laws: The use of navigation lights ensures that vessels operate according to international regulations, reducing risks and protecting lives, vessels, and cargo.

Communication of Vessel Type and Status: The color and configuration of marine navigation lights communicate the vessel's operation—whether it is engaged in fishing, towing, sailing, or anchored. This identification helps vessels understand each other's activities and take the appropriate precautions.

International Standards and Regulations for Marine Navigation Lights

The International Regulations for Preventing Collisions at Sea (COLREGs), established by the IMO, provide the global framework governing the use of navigation lights. These regulations specify the color, visibility range, and configuration of marine navigation lights for various vessel types and conditions.

Key Regulatory Factors:

Color: The use of specific colors (red, green, white, and yellow) is designated for different vessel positions and operations.

Arc of Visibility: Navigation lights must be visible from particular angles, depending on the vessel’s type and size.

Range of Visibility: Lights must be visible from a minimum distance, ensuring they function effectively in poor visibility conditions, such as fog or rain.

Color Standards for Marine Navigation Lights

Red Light (Port Side)

Direction Indicator: Positioned on the port (left) side of the vessel, the red light indicates the vessel’s left side when viewed from the front. It signals to other vessels to yield and avoid crossing in front of the vessel.

Visibility: Covers an arc of 112.5 degrees from directly ahead to slightly behind the port beam, ensuring visibility from the front-left side of the ship.

Green Light (Starboard Side)

Direction Indicator: Located on the starboard (right) side, the green light indicates the vessel’s right side from the front, typically signaling that the approaching vessel has the right of way.

Visibility: Similar to the red light, it covers 112.5 degrees from directly ahead to slightly behind the starboard beam.

White Light

Masthead Light: Positioned on the centerline of power-driven vessels, visible over a 225-degree arc, indicating the forward position. Larger vessels may display multiple masthead lights.

Visibility Range: Typically visible for 5–6 nautical miles, depending on vessel size.

Stern Light: Located at the vessel’s rear, covering a 135-degree arc, making it visible to vessels approaching from behind.

Visibility Range: Typically visible from 2–3 nautical miles.

Anchor Light: A 360-degree white light displayed by stationary vessels to indicate they are anchored.

Visibility Range: At least 3 nautical miles.

Yellow Light

Special Operations: Used for towing or fishing vessels, yellow lights indicate specific activities.

Visibility Range: Similar to stern or masthead lights, depending on the specific vessel type and operation.

Additional Light Configurations for Special Vessels

Fishing Vessels: May use a combination of red and white lights to indicate fishing operations.

Towing Vessels: Display yellow and white lights to signal towing activities.

Visibility Standards for Marine Navigation Lights

Visibility Range by Vessel Size

Power-Driven Vessels over 50 Meters

Masthead Light: Visible from at least 6 nautical miles.

Side Lights (Red and Green): Visible from at least 3 nautical miles.

Stern Light: Visible from 3 nautical miles.

Towing Light: Visible from 3 nautical miles.

Power-Driven Vessels between 12 and 50 Meters

Masthead Light: Visible from at least 5 nautical miles.

Side Lights: Visible from 2 nautical miles.

Stern Light: Visible from 2 nautical miles.

Power-Driven Vessels under 12 Meters

Masthead Light: Visible from 2 nautical miles.

Side Lights: Visible from 1 nautical mile.

Stern Light: Visible from 2 nautical miles.

Sailing Vessels and Vessels under 20 Meters

Side Lights, Stern Lights, and All-Round White Lights: Visible from at least 2 nautical miles.

Vessels at Anchor

Anchor Light: Visible from at least 3 nautical miles. For vessels over 50 meters, additional lights may be required.

Arc of Visibility

Masthead Light: Must be visible over an arc of 225 degrees, covering the front and sides of the vessel.

Side Lights (Red and Green): Must be visible over an arc of 112.5 degrees on their respective sides, allowing other vessels to distinguish between port and starboard.

Stern Light: Visible over a 135-degree arc, showing light from behind the vessel.

All-Round Lights (e.g., Anchor Lights): Must be visible over a full 360-degree arc, ensuring visibility from any direction.

Technical Considerations for Marine Navigation Lights

Light Intensity and Range

Navigation lights must have sufficient luminous intensity to ensure visibility over regulated distances:

Vessels under 12 meters: Visible for 2 nautical miles.

Vessels between 12 to 50 meters: 3 nautical miles for side lights and up to 5 miles for masthead lights.

Vessels over 50 meters: Visible up to 6 nautical miles for masthead lights.

Beam Angle and Coverage

Side lights: Visible over 112.5 degrees.

Masthead lights: Must cover 225 degrees.

Stern lights: Must cover 135 degrees.

Power Source and Energy Efficiency

LED Technology: Preferred LED navigation signal light due to low energy consumption, long lifespan, and reliability in harsh conditions.

Backup power systems should ensure continuous operation during power failures.

Durability and Weather Resistance

Navigation lights must resist corrosion, saltwater, UV radiation, and mechanical impact. Waterproof ratings (IPX7 or IPX8) ensure protection against water ingress.

Height and Positioning

Masthead lights should be positioned as high as possible for maximum visibility, especially for larger vessels.

Side lights should not be obstructed by the vessel's structure or cargo.

Light Synchronization and Control

On larger vessels or those engaged in special operations, light synchronization helps other vessels accurately interpret the vessel’s status. Automated systems can monitor light performance and adjust intensity based on environmental conditions.

Conclusion

By adhering to international regulations for color and visibility, marine navigation lights enhance maritime safety, allowing vessels to navigate safely and communicate effectively with others. Ensuring proper intensity, range, and configuration of lights helps prevent collisions and supports compliance with maritime laws, ultimately protecting lives and cargo.