🔍 Key Concepts

• International Regulations for Preventing Collisions at Sea (COLREGS) and where they start to apply geographically • Difference between Inland Rules and International Rules on U.S. waters • How chart diagrams and boundary lines show where rule changes occur

💭 Think About

• Think about which of these options describes a legal or charted boundary between Inland and International Rules rather than just a position or bearing. • Ask yourself: Which answer mentions something that would be shown on a COLREGS demarcation line or territorial sea limit on a chart? • Consider which items (light bearings, buoys, sea boundary, contiguous zone) are used in practice to tell mariners when they must change from Inland to International Rules.

✅ Before You Answer

• Look at a coastal chart and find the COLREGS Demarcation Line and territorial sea boundary lines—note how they’re labeled. • Verify which answer choice refers to a legal maritime boundary versus a simple navigational reference point (like a light bearing or a single buoy). • Confirm in the Navigation Rules that Inland vs. International application is tied to specific demarcation lines, not just any offshore zone boundary.