NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

HOME

Re: Silicon Sea, Leg 12 question
From: Renee Mattie
Date: 2006 Jul 7, 14:20 -0500

In the 10 years since the problems were written, EXCEL makes it much easier to check and plot these things.

There are other anomalies in the first 7 legs, but I think most of them can be explained away, assuming nobody logged conditions on that bit of water at the same time!

Renee

From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Peter Fogg peter.fogg-at-gmail.com |Renee Mattie on NavList|
Sent: Thursday, July 06, 2006 6:22 PM
To: .....................
Subject: [NavList 518] Re: Silicon Sea, Leg 12 question

Renee wrote:

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.

All of this seems quite correct. There does seem to be an anomaly here.

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.

If this rejigging fits the scenario better then that seems fine. You may have been the first to notice this inconsistency. Well spotted.

--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

Subject:
Author:
Start date:	(yyyymm dd)
End date:	(yyyymm dd)

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

NavList

What is NavList?

Get a NavList ID Code

Retrieve a NavList ID Code

Email Settings

Custom Index

Add Images & Files
Name or NavList Code:	Email:

Name:
	(please, no nicknames or handles)
Email:

NavList ID Code: