Your vessel is steering 143°T at 16 knots....

Question 1 of 2707066636ee928f7522a1c51a657

Your vessel is steering 143°T at 16 knots. At 2147 a light bears 106°T and at 2206 the same light bears 078°T. What will be your distance off when abeam?

Back

Question 1 of 27070

Your vessel is steering 143°T at 16 knots. At 2147 a light bears 106°T and at 2206 the same light bears 078°T. What will be your distance off when abeam?

🔍 Key Concepts

• Convert the two observed bearings to relative bearings from your ship’s heading 143°T to see how the light moves on your bow. • Use the distance run between the two observations (speed × time) and sketch the ship’s track with two positions and a fixed light. • Remember that the distance off when abeam is just the perpendicular distance from your track line to the light, which does not change as you pass.

💭 Think About

• How many miles do you travel between 2147 and 2206 at 16 knots, and how can that become one side of a triangle in your sketch? • Once you know the relative bearings at the first and second sighting, what right triangles can you form between the ship, the light, and the track? • How can you use basic trigonometry (like tangent = opposite/adjacent) to relate the forward distance along track to the constant perpendicular distance (distance off)?

✅ Before You Answer

• Be sure you correctly convert true bearings to relative bearings by comparing them with your course of 143°T (is the light to port or starboard?). • Confirm your time difference in hours before multiplying by 16 knots to get distance run. • Before choosing an answer, check that your final distance off is reasonable compared to the distance run between bearings and that it matches the geometry in your sketch.