🔍 Key Concepts

• U.S. Aids to Navigation System (IALA-B) – how colors and shapes mark the right and left banks when heading upstream on the Mississippi/Western Rivers • Difference between daymark color (red vs green) and shape (triangle vs square/diamond) for lateral marks • How mile numbers (AHP – Above Head of Passes) relate to the normal direction of buoyage on the Mississippi River

💭 Think About

• Ask yourself: When you’re going upbound on the Mississippi (increasing mile numbers AHP), which side is marked by red aids and which by green aids? • Determine whether French Point Light at mile 915.4 AHP is on the right descending bank or left descending bank, and how that translates when you are going upstream. • Recall which shape (triangle vs square/diamond) is normally associated with the right-hand side of the channel in the IALA-B system.

✅ Before You Answer

• Verify the direction of buoyage on the Mississippi River (AHP – Above Head of Passes means upstream). • Confirm which combination of color and shape marks the right-hand side when going upstream in the Western Rivers system. • Make sure the answer you pick matches both the correct color for that side of the river and the correct daymark shape for that lateral mark.