Your vessel is proceeding up a channel, and...

Your vessel is proceeding up a channel, and...

Question 1 of 2921866636ee928f7522a1c51a636

Your vessel is proceeding up a channel, and you see a pair of range lights that are in line ahead. The chart indicates that the direction of this pair of lights is 352°T, and the variation is 4°W. If the heading of your vessel at the time of the sighting is 359° per standard magnetic compass, what is the correct deviation?

Question 1 of 29218

Q

Your vessel is proceeding up a channel, and you see a pair of range lights that are in line ahead. The chart indicates that the direction of this pair of lights is 352°T, and the variation is 4°W. If the heading of your vessel at the time of the sighting is 359° per standard magnetic compass, what is the correct deviation?

🔍 Key Concepts

• Variation vs. Deviation – know the difference and which one comes from the chart vs. the compass • The rule: "True ± Variation = Magnetic; Magnetic ± Deviation = Compass" and how the signs work for East/West • How range lights tell you the true direction of your ship when they are exactly in line

💭 Think About

• First, convert the charted range bearing (given in °T) to magnetic using the given variation. Think carefully: do you add or subtract a west variation? • Next, compare that magnetic heading (the one you should be on when lined up with the range) with your standard magnetic compass heading to find deviation. • Decide whether the deviation must be east or west based on whether the compass is reading higher or lower than the magnetic direction.

✅ Before You Answer

• Verify you correctly applied 4°W variation when going from True to Magnetic (remember the standard "East is least, West is best" rule when converting). • Check that you are using the compass heading given in the problem, not reusing the true or magnetic value by mistake. • Confirm the sign of deviation: if the compass reads more than magnetic, is that east or west deviation? Be sure before choosing.