Question 29 RVR05 - Master of LT 100 GRT

The Correct Answer is B Option B, the **alternately flashing red and yellow light**, is correct because it is the specific, federally mandated signal authorized for commercial vessels engaged in public safety activities operating on inland waters under U.S. federal regulation. Specifically, 33 CFR 88.11 (Inland Rules) states that a vessel engaged in law enforcement or public safety activities may display an alternately flashing red and yellow light signal. This signal is designed to clearly identify vessels performing these essential services, such as search and rescue, law enforcement, or firefighting, and is unique to this function under the Inland Navigational Rules Act of 1980. ### Why the other options are incorrect: * **A) flashing yellow light:** A single flashing yellow light (or amber light) is typically used on inland waters to signify an air cushion vessel operating in the non-displacement mode, or on certain other vessels like dredge pipelines, but it is not the required identification light for public safety vessels. * **C) alternately flashing blue and red light:** While this combination is commonly associated with emergency vehicles (police, fire) on land, it is **not** the recognized or authorized signal for vessels engaged in public safety activities under the Inland Navigational Rules. Marine regulations require the red and yellow combination (Option B). * **D) flashing blue light:** A flashing blue light on inland waters is specifically reserved for vessels engaged in **law enforcement** activities and is displayed only by officially recognized law enforcement vessels. While public safety activities include law enforcement, the question asks for the light identifying a vessel engaged in *public safety activities* broadly, which is the alternating red and yellow light. The flashing blue light is a subset signal reserved only for police functions, making the alternately flashing red and yellow light the most appropriate signal for general public safety vessels (which encompasses fire, search and rescue, etc.).