How many main types of buoyage systems are recognized under the IALA system?

The IALA Maritime Buoyage System recognizes two main types of buoyage systems: the IALA Region A and IALA Region B systems. These two systems serve to provide navigational aids that help mariners determine safe pathways through waterways.

Regional differences arise from varying local practices, which may influence buoyage colors, shapes, and light characteristics. The main distinction between the two regions lies in the marking of navigational channels and hazards. Region A predominantly utilizes red on the left side when entering a harbor, while Region B uses green for the left side under the same circumstances.

Understanding this duality is crucial for mariners as they navigate across different regions, ensuring that they correctly interpret navigational aids to enhance safety at sea. The option stating two types reflects this fundamental structure of the IALA buoyage system.