Question 1 of 2707066636eea28f7522a1c51b7f0

Your vessel receives a distress call from a vessel reporting her position as LAT 35°01.0'S, LONG 18°51.0'W. Your position is LAT 35°01.0'S, LONG 21°42.0'W. Determine the true course and distance from your vessel to the vessel in distress by parallel sailing.

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Question 1 of 27070
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Your vessel receives a distress call from a vessel reporting her position as LAT 35°01.0'S, LONG 18°51.0'W. Your position is LAT 35°01.0'S, LONG 21°42.0'W. Determine the true course and distance from your vessel to the vessel in distress by parallel sailing.

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🔍 Key Concepts

• Parallel sailing when two positions are on (approximately) the same latitude • How to find the difference of longitude (DLO) between two longitudes, paying attention to E/W • The relationship between departure, DLO, and cosine of latitude

💭 Think About

• Are the two vessels north-south of each other, or mainly east-west of each other? What does that suggest about the approximate true course? • Compute the difference in longitude between 21°42.0'W and 18°51.0'W. Is your vessel east or west of the distress vessel? • Once you have the DLO in minutes of arc, how do you convert that to departure at a given latitude using parallel sailing? Does that give you a shorter or longer distance than the raw DLO in miles?

✅ Before You Answer

• Confirm both latitudes are exactly the same so that parallel sailing is appropriate • Be sure you identify correctly which longitude is farther west and which is farther east to choose between 090°T and 270°T • After calculating distance, compare it with both 140.0 miles and 189.2 miles to see which is closest to your computed value