Question 1 AB01 - Able Seafarer

The Correct Answer is D. **Why option D ("An unlighted can buoy") is correct:** In the lateral system of navigational aids (used primarily in the U.S. and conforming to IALA Region B rules), aids marking the sides of a channel are numbered. When returning from sea (entering port or heading upriver), the aids on your **port** (left) side are odd-numbered. These buoys are typically green (or green-and-red striped). A **can buoy** is a specific type of buoy shape—cylindrical—that is used to designate the **port** side of the channel. Since port-side buoys are odd-numbered, an unlighted can buoy will carry an odd number. **Why the other options are incorrect:** * **A) A yellow buoy:** Yellow buoys are generally used for special purpose marks (e.g., anchorage areas, dredging, scientific instruments) and are *not* part of the lateral (channel numbering) system. They may be lettered, but they are not typically odd-numbered. * **B) A spherical buoy:** Spherical buoys are characteristic of safe water marks (mid-channel marks). These buoys are white and red vertical stripes, and they are usually designated with a letter (or sometimes a number *preceded* by a letter, such as "A1"), but they do not participate in the odd/even sequential numbering of the lateral system. * **C) A red buoy:** Red buoys mark the **starboard** (right) side of the channel when returning from sea. In IALA Region B, these buoys are always **even** numbered.