You are on course 317° T at 13 knots. A...

Question 1 / 27070

Question 1 of 2707066636eea28f7522a1c51aff4

You are on course 317° T at 13 knots. A light is bearing 22.5° relative at 0640. At 0659 the same light is bearing 45° relative. At what time should the light be abeam?

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Question 1 of 27070

You are on course 317° T at 13 knots. A light is bearing 22.5° relative at 0640. At 0659 the same light is bearing 45° relative. At what time should the light be abeam?

🔍 Key Concepts

• Relative bearings vs. true bearings and what "abeam" means in relative terms • Using constant speed and linear change in bearing to estimate when a relative bearing will reach 90° • Setting up a simple time–bearing proportion to find the unknown time

💭 Think About

• How many minutes passed between the 22.5° relative bearing and the 45° relative bearing, and what is the total change in relative bearing during that period? • If the bearing is changing at a steady rate, how long would it take for the bearing to change from 45° relative to 90° relative (abeam) at the same rate? • Once you know the extra time needed from the second observation to reach 90°, what clock time does that give you for the abeam position?

✅ Before You Answer

• Confirm that abeam on your own vessel means a 90° relative bearing (right or left, depending on what side the light is on). • Check that you are assuming constant speed and steady course, so the change in bearing per minute is uniform. • Recalculate the bearing change per minute carefully to avoid arithmetic mistakes before adding time to 0659.