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Author
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Topic: Workbook 4-14 measure a radar range of 4.5miles,,
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tfrederick
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posted March 12, 2026 02:37 PM
This question of steering a course of 075M from New Dungeness Buoy 2, you measure a "radar range of 4.5 nmi at relative bearing of 045R to the north of Protection Island." Up to this point in the book I did not find anything pertaining to figuring in a "radar range"? In QTVLM I used the "ruler tool", started at New Dungeness Buoy 2 and went 4.5nmi on a course of 075M which brought me to 48° 11.090N 122° 58.9830W in a depth of 54 fathoms which is outside of the shipping lanes. I saw very little 45° off of my bow? Your answer of 48° 11.4'N, 123° 00'W in 60±3 fathoms (although I fail to see 60±3 fathoms) is right on the meridian and on the inside of the shipping lane but is only 3.81nmi from Buoy 2 and in 52-60 fathoms? Can you explain where I'm going wrong?
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Dave Wilkinson
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posted March 13, 2026 03:46 PM
The glossary is helpful here. See "radar range" where we find that it is just a range determined by radar.
Also, the term "relative bearing" explains the meaning of 045R.
One approach would be to set a mark on the northern tip of Protection Island with a circle of 4.5 nmi. Then see where the circle crosses your 075M course from Buoy 2. That intersection should be close to the coordinates for A. The relative bearing should confirm this location.
From: Starpath, Port Townsend WA
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David Burch
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posted March 14, 2026 04:17 PM
Topic in wrong Forum. I will move it back to the Student Discussion Forum.
From: Starpath, Seattle, WA
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Topic Closed
