Why is it critical to maintain a 3-minute fix interval in restricted waters?

Maintaining a 3-minute fix interval in restricted waters is crucial primarily to ensure navigational safety. In these environments, where depths are shallow, and obstacles may be present, frequent position updates provide timely information that helps in making informed decisions concerning the vessel's navigation. The potential for hazards increases in restricted areas, and having an accurate understanding of the vessel's position mitigates the risk of grounding or colliding with underwater obstructions or other vessels.

Further, this practice allows for a quick response in the event of an unexpected navigational challenge, as the more frequently positions are recorded, the better a watch officer can monitor and adjust course as necessary. Continuously tracking the vessel’s location in relation to charted hazards leads to increased situational awareness, ultimately enhancing the safety of navigation in these complex and potentially risky environments.