The sternlight's visible arc around dead astern to each side of the stern is how many degrees?

The sternlight's visible arc around dead astern to each side of the stern is how many degrees?

• A. 67.5 degrees
• B. 22.5 degrees
• C. 135 degrees
• D. 90 degrees

Answer: (A)

The question is about how far the stern light extends to each side of dead astern. The stern light is a white light that must be visible over an arc of 135 degrees centered on dead astern. That means the light reaches 67.5 degrees to the left and 67.5 degrees to the right of the straight-back line. So the per-side arc is 67.5 degrees, making the total arc 135 degrees. The other numbers don’t apply to this light: 135 degrees is the full arc, not the per-side reach, and 90 or 22.5 degrees aren’t the standard stern-light measurements.

The question is about how far the stern light extends to each side of dead astern. The stern light is a white light that must be visible over an arc of 135 degrees centered on dead astern. That means the light reaches 67.5 degrees to the left and 67.5 degrees to the right of the straight-back line. So the per-side arc is 67.5 degrees, making the total arc 135 degrees. The other numbers don’t apply to this light: 135 degrees is the full arc, not the per-side reach, and 90 or 22.5 degrees aren’t the standard stern-light measurements.