Your vessel receives a distress call from a...

Question 1 of 2707066636eea28f7522a1c51b7f4

Your vessel receives a distress call from a vessel reporting her position at LAT 5° 24' N, LONG 31° 16' W. Your position is LAT 2° 39' S, LONG 39° 24' W. Determine the distance from your vessel to the vessel in distress by Mercator sailing.

Back

Question 1 of 27070

🔍 Key Concepts

• Mercator sailing uses a difference of longitude and a meridional part difference to find distance on a Mercator chart. • You must convert all latitudes to same-named (both North or both South) or carefully handle crossing the equator when finding ΔLat and ΔLong. • Use the right triangle concept: one side is the difference of latitude, the other is the departure (related to ΔLong and mean latitude), and the hypotenuse is the distance.

💭 Think About

• First, compute the difference of latitude between the two positions, being careful that one is North and one is South. How do you combine them? • Next, find the difference of longitude, making sure you stay within 0°–180°. Are both longitudes west, and what does that mean for ΔLong? • In Mercator sailing, how do you get from ΔLong and the meridional parts to the distance? Think about which trigonometric function (tan, sin, cos) connects course angle and ΔLong/meridional difference.

✅ Before You Answer

• Confirm your ΔLat sign and magnitude: one latitude is N and the other is S, so do you add or subtract when finding the total change? • Verify your ΔLong is correct: both longitudes are west—do you subtract or take the difference between them? • After computing distance, check if it is a reasonable mid-latitude ocean passage for a few degrees of separation in both latitude and longitude; eliminate any option that is clearly too small or too large.