Marine navigation signal lights, also known as running lights or steering lights, are an essential part of maritime safety. They are used to indicate a vessel's position, movement, and sometimes its type, to other vessels during hours of darkness or in conditions of reduced visibility. This article delves into the color rules governing maritime navigation lights and the meanings behind different colors.

The International Regulations for Preventing Collisions at Sea (COLREGs)

The foundation of marine navigation signal light rules lies in the COLREGs, a set of international regulations adopted by the International Maritime Organization (IMO) to standardize the use of lights and signals at sea. These regulations are designed to reduce the risk of collisions by ensuring that all vessels are identifiable and their movements are understood.

Color Rules and Their Significance

1. Masthead Lights
   • White: The masthead lights are always white and are placed at the highest point of the vessel. They are visible from 225 degrees ahead from straight ahead to 22.5 degrees on either side of the vessel. These lights indicate the vessel's presence and height.
2. Stern Light
   • White: The stern light is also white and is placed at the stern of the vessel. It is visible astern and indicates the vessel's rear position.
3. Sidelights (Port and Starboard Lights)
   • Green: The port light is green and is placed on the left side of the vessel when viewed from on board, indicating to other vessels that this is the vessel's port side.
   • Red: The starboard light is red and is placed on the right side of the vessel when viewed from on board, indicating to other vessels that this is the vessel's starboard side.
4. Additional Lights
   • Red and Green Overtaking Lights: When one vessel is overtaking another, the overtaking vessel may show a high red light forward and a high green light aft to indicate its intention to overtake.
   • All-Round Lights: These are white lights visible in all directions and are used to indicate various conditions such as a vessel not under command, a vessel restricted in its ability to maneuver, or a vessel engaged in fishing.

Understanding the Color Code

• Green (Port Light): The green light on the left side indicates that the side of the vessel is the rear as seen from the vessel's bow. It signifies that other vessels are approaching the overtaking vessel from behind.
• Red (Starboard Light): The red light on the right side indicates that the side of the vessel is the front as seen from the vessel's bow. It signifies that other vessels are approaching the overtaking vessel from the side.
• White Lights: White is used for masthead lights, stern lights, and all-round lights. The masthead lights indicate the vessel's height and presence, the stern light indicates the rear of the vessel, and all-round lights are used in various situations to indicate specific conditions or restrictions.

Importance of Adherence

Adherence to the color rules for navigation lights is crucial for safe navigation. Misunderstanding the meaning of these lights can lead to collisions or near misses. Color rules for navigation lights are an important part of safety at sea, they help avoid collisions and misunderstandings.

Marine navigation signal lights are a maritime language that all seafarers must understand. The colors green, red, and white have specific meanings that, when combined with a vessel's other lights and signals, help to prevent collisions at sea. By following the COLREGs and maintaining proper navigation lights, vessels can safely navigate the world's oceans and waterways, day and night. For more in-depth information on maritime navigation lights and their regulations, seafarers and maritime enthusiasts can refer to the COLREGs and related IMO publications.