45. Your vessel is steady on a heading of 160° per standard magnetic compass when you sight Southwest Ledge Light and New Haven Outer Channel Range Rear Light in line dead astern. What is the deviation of the compass based on this observation?

The observation of two range lights in line dead astern indicates the vessel is on the range line, allowing calculation of deviation as the difference between the magnetic course of the range and the compass heading; the compass heading of 160 is 2 less than the magnetic course, resulting in a 2E deviation.