How do ships navigate safely across the vast ocean? The buoy system established by the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) acts as a "traffic light" on the water, using a unified visual language to guide ships worldwide. This system has become the universal "grammar" of international shipping.
The IALA buoy system is divided into two major regions, A and B, similar to the differences in traffic rules on land:
• A System (Left Red, Right Green):
Adopted in Europe, Africa, Australia, and most of Asia. When vessels enter a port, the left buoy is red (cylindrical or cylindrical), and the right buoy is green (conical), with corresponding red and green flashing lights.
• B System (Left Green, Right Red):
Applies to the Americas, Japan, South Korea, the Philippines, and Taiwan, with rules opposite to the A system: the left buoy is green, and the right is red.
Special cases: Some ports in Taiwan still retain the old system of "right red, left black," while the Ryukyu White Sand Port uses the B system, highlighting the complexity of actual operations.
The IALA buoy system conveys critical information through five types of markers, each with strict international standards:
1. Side Markers (Channel Boundaries)
o Red/Green Buoys: Indicate the left and right boundaries of the channel. In System A, red is on the left and green on the right; in System B, the opposite applies.
o Branch Point Markers: Red and green horizontal stripes (main channel on the right) or green and red horizontal stripes (main channel on the left), with mixed flashing lights (e.g., 2+1 rhythm).
2. Directional Markers (Safety Quadrants)
Combining black and yellow stripes with conical top markers to indicate the direction of safe water areas:
o North directional marker: Both conical tips pointing upward (mnemonic: "Up North")
o South directional marker: Both conical tips pointing downward (mnemonic: "Down South")
o Lights are white fast flashes or very fast flashes, with rhythms corresponding to different quadrants.
3. Safe Water Markers (Deep Water Channels)
Red and white vertical stripes + spherical top mark, indicating the center of the channel or the deep water area at the entrance, with white steady lights (e.g., long flash every 10 seconds).
4. New Hazard Buoys (Emergency Warning)
Blue and yellow vertical stripes + fast-flashing light (e.g., Fl(5)), used for temporarily marking new obstacles such as sunken vessels, requiring deployment within 72 hours and synchronization with electronic chart updates.
Traditional buoys are increasingly integrating with digital technology:
• Norwegian MOTUS buoys: Integrated with wave sensors and Doppler current profilers (DCPS), broadcasting real-time sea conditions via AIS, allowing vessels to receive data without additional equipment.
• China's e-Navigation Strategy: Pilot projects at Yangshan Port, Meizhou Bay, etc., integrate Beidou positioning, AIS, and VTS systems to achieve end-to-end monitoring from berth to berth.
For example: When a storm causes the buoy to drift, the system automatically calculates the radius of gyration (formula R ∝ anchor chain length L/water depth H) and remotely corrects the position data in real time.
The significance of this unified system is profound. In the Malacca Strait, vessels from around the world rely on IALA buoys for orderly avoidance; in the Panama Canal, Zone B rules ensure precise lock entry for east-west vessels. Data shows that since the IALA system was implemented in 1977, the collision rate of vessels in international waters has decreased by 62%. As the nautical proverb goes, "Buoys are silent pilots"; the rules established by IALA enable this silent guidance to transcend national borders, becoming the cornerstone of maritime trade safety.
