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Thanks for your comments, Peter.  As I said when I began, I intend to learn
a lot during this project, so I have examined every detail of the first 3
problems very carefully.  So far, my progress has been very slow.  I have
spent a lot of time building skills.  And I have to be pretty slow and
careful in the application of the skills I have.

I have not found any errors in the answers.  I know the answers had been
well vetted, so I was looking for errors in my approach to solving the
problems. I did find something unusual in leg 12, however.

In problem 11, Silicon Sea is traveling on a course of from about 92 to 96
true.

At the beginning of problem 12, it has just traveled for 30 hours on a
course of 96.2 T, 7.5 knots, arriving at 09-22-00 GMT at 38d 31.5'N 10d
25.6'E, 12.9 nmi from its waypoint in the Strait of Sicily.

Then, in problem 12-3, at 11-17-16 GMT, the vessel takes a Noon Latitude
from a DR position of 38d 35.0'N 09d 45.7'E, 44.5 nmi from the waypoint.  In
order to have gotten to the 11-17 position from the 09-22 position in 2
hours, the vessel would have had to have sailed for 2 hours at 276 true,
16.4 knots.

I have decided to avoid this "reversal of course" problem without changing
the Noon Latitude position -- simply slow the vessel down a bit, and alter
the 09-22 GMT DR position.  I cannot think of a plausible "story line" to
explain reversing course for 2 hours, so I think this slight rewriting is
more true to the original intent.

Renee



-----Original Message-----
From: Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM]
On Behalf Of Peter Fogg
Sent: Sunday, June 25, 2006 7:01 AM
To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
Subject: Re: [NAV-L] Silicon Sea, Leg 12 question

Renee wrote, on 18 June:
> And now I've moved on to puzzling over problem 12.  Like why, at 0922
> (or is it 1022) the vessel switches to a course of 77.5T when it has
> been on a CMG of about 96.2 for the past 2 days.

Leg 12 begins with a (true) course of 096d. Question 1 asks for a DR
position and that time is 0922 GMT on 12 May 1996. After question 3 "we
decide to alter course" to 111d (also true).

After question 5 "The wind shifts...the current shown..." and the COMPASS
course becomes 106d.

I've gone through Leg 12 without finding any significant differences to the
official answers.

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