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» Online Classroom   »   » Public Discussion of Inland and Coastal Navigation   » Problems 5-10 & 5-15

Author Topic: Problems 5-10 & 5-15

 - posted February 16, 2008 12:49 PM      Profile for SRF           Edit/Delete Post 
Greetings, all! I am currently working through the Chart Problems Section 5 & wanted to check a couple of questions.
Q5-10 concerns doubling the bow angle to find distance off. Answer A = 352M seems to me to be in error, because the doubled bow angle of 80 degrees has been added to the course heading instead of to the initial bearing to the target. My answer is 80 + 312 = 392 (minus 360 = 032).
Q5-15, running fix including wind and current vectors. Answer C = 2.25 miles seems to me to be derivable only if the given current is 2.0 kts due south rather than 1.0 kts due south. My answer is that the distance to the buoy is only about 2.0 nmi.
I wanted to check because I am not sure if my reasoning and plotting is correct or incorrect. Thanks for the help, and thanks also for this excellent course. Steve Frazer

David Burch

 - posted February 17, 2008 10:07 PM      Profile for David Burch           Edit/Delete Post 
to double the bow angle, take (bearing - heading) that is bow angle 1 then dobule that, then add that to the heading to get the next bearing you would look for. Maybe do that then work it backwards from there to see that it is right.

Note Problem 5-15 is a leeway problem, with no new currents. Did you get 5-14 correct and does it make sense?

Note that 5-14 has been discussed elsewhere in the course which led to a correction in the tech suppport section. search on 5-14

From: Starpath, Seattle, WA

 - posted February 20, 2008 04:17 PM      Profile for SRF           Edit/Delete Post 
Thank you for the help. I clearly see my mistake on the compass / double the heading problem, & am working on the leeway plotting. SRF

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