Question 2

The Correct Answer is C ### Why Option C ("white stern light") is correct: 1. **Context:** The illustration (D017RR) describes a scenario where Vessel "A" is the overtaking vessel and Vessel "B" is the vessel being overtaken. Vessel A "will pass without changing course," meaning it is approaching Vessel B directly from the stern (behind). 2. **Rule Application (International/Inland Rule 23):** Navigational lights are designed so that a vessel sees specific lights depending on the angle of approach. 3. **Stern Light Definition:** A white stern light is mandated to show an unbroken light over an arc of the horizon of $135^{\circ}$ (or $112.5^{\circ}$ on each side of the stern) and fixed so as to show the light as precisely as possible from directly astern. 4. **Observation:** Because Vessel A is overtaking Vessel B (approaching from astern), the only navigational running light Vessel A will see on Vessel B is the **white stern light**. ### Why the other options are incorrect: * **A) green sidelight:** The green sidelight shows light over an arc of $112.5^{\circ}$ from dead ahead to $22.5^{\circ}$ abaft the beam on the starboard (right) side. Since Vessel A is approaching from astern (the rear), it is outside the arc of visibility for the green sidelight. * **B) yellow towing light:** The yellow towing light is required only for vessels engaged in towing (Rule 24). It is positioned above the stern light and covers the same arc of $135^{\circ}$. While Vessel B *might* be towing, the stern light (C) is the guaranteed basic running light visible from the stern on *all* power-driven or sailing vessels at night. Therefore, the simple, necessary light visible when overtaking is the white stern light, making it the most accurate primary observation. * **D) None of the above:** This is incorrect because the white stern light is clearly visible in this overtaking situation.