What is the purpose of a lateral mark in the IALA system?

The purpose of a lateral mark in the IALA system is to define the lateral limits of a navigable channel. Lateral marks are specifically designed to indicate the sides of a channel to assist mariners in safely navigating through restricted waters. They help vessels determine their position relative to the channel boundaries, ensuring that they remain within safe limits while avoiding hazards and maintaining safe navigation.

These marks are color-coded and often feature specific shapes, which communicate important navigational information. For instance, in the IALA Region A system, port side marks are typically green and starboard side marks are red, providing a clear visual cue for navigation. This use of lateral marks is critical for maintaining safe passage through waterways where depth and space may be limited or where there could be underwater obstructions.