🔍 Key Concepts

• U.S. Aids to Navigation System (ATON) shapes for daymarks on fixed structures (see 33 CFR Part 62) • Difference between lateral marks (port/starboard channel markers) and non‑lateral/special purpose marks • Typical shapes used for regulatory / special purpose signs versus standard channel markers

💭 Think About

• First, identify which shapes in the illustration are normally used for port and starboard lateral daymarks. Once you know those, you can eliminate them from the choices. • Next, look at the remaining shapes and ask: which one is associated with information, regulatory, or special purpose areas rather than marking the edges of the channel? • Think about what shape you see on fixed signs that mark restricted areas, danger areas, or other special zones, and match that to the illustration.

✅ Before You Answer

• Verify which shapes are used for lateral daymarks: square/rectangular and triangular boards, and cross off those letters. • Check which of the remaining shapes is commonly used as a regulatory/special purpose sign on fixed structures in the U.S. system. • Make sure the shape you pick is not the standard port (square) or starboard (triangle) channel marker shape.