Question 33 TV01 - Towing Vessels - Oceans or Near Coastal

The Correct Answer is B **Explanation for Option B (67.5°):** Option B (67.5°) is correct because it aligns precisely with the requirements specified in the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules (which generally harmonize with COLREGs regarding light arcs). The definition of the **Stern Light** (Annex I, 9(d) of COLREGs) states that it is a white light placed as nearly as practicable at the stern showing an unbroken light over an arc of the horizon of **135 degrees** and so fixed as to show the light $67.5$ degrees from right aft on each side of the vessel. Thus, the light is positioned to show from dead astern to $67.5$ degrees on each side of the stern. ($67.5° + 67.5° = 135°$). **Explanation for Incorrect Options:** * **A) 22.5°:** This figure is related to the required minimum visibility range (in nautical miles) for certain lights on smaller vessels, or it is the arc of the steaming light's forward cut-off point *past* the beam (i.e., it is the arc of the side lights showing forward of the beam up to the required $112.5^\circ$ total arc). It is not the arc for the stern light on one side. * **C) 112.5°:** This figure represents the total arc of visibility for the **sidelights** (green and red lights), extending from the bow to $22.5$ degrees abaft the beam on its respective side. It is not the arc for the stern light on one side. * **D) 135.0°:** This figure represents the **total** arc of visibility for the stern light (from port aft to starboard aft). The question asks for the arc on **each side** of the stern.