Student
Conan Hom
Lexington, MA, USA
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Crew Level 0
Status: Sailor
Qualified days: 8
Posted 2018, Apr 23 03:14
If deviation is a function of the magnetic heading heading then if we know the true heading we can calculate the ships compass (true + variation +deviation). However if we have the ships compass reading and we know the variation but we wish to have the true heading, is it possible to find the true heading? I'm not so sure because we won't know the deviation (since we don't know the magnetic heading which is necessary to calculate the deviation). Is this a correct assessment?
Student
Conan Hom
Lexington, MA, USA
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Crew Level 0
Status: Sailor
Qualified days: 8
Posted 2018, Apr 23 12:03
In Module 3: Currents and Tides, the instructions specify to add leeway to the heading first whereas here in this section one add lee way after the heading and current. There may be a contradiction here that needs to be resolved.
Student
Michael Kazek
Benicia, CA, USA
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Skipper Level II
Status: Sailor
Qualified days: 43
Posted 2018, May 27 17:47
Latest download for Chart 12354 is the 46th Ed, Feb 2017 and was last updated on 4/27/2018. Stone reef lighthouse is now a Fl 2.5s 22 ft 7M light. So depending on what version of Chart 12354 we are using, some of the references to lights in the example problems may not be the same. As a note, the fix plotted puts us about 1.5 nm off our DR course of 180 psc or 164 T. If you have us start off of Hammonasset Pt and head 180 psc, the fix is a little closer to our DR.
Student
Carlos Bazan
Santiago, Chile
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Skipper Level I
Status: Sailor
Qualified days: 11
Posted 2018, Jul 29 00:58
In the last exercise it's said that the true heading is 47º.
According to the last deviation table, the 50º compass heading gives us an approximate deviation of 4º.
If we apply M = C + D, we would obtain 54º M.
Now to obtain the true heading, we should subtract the corresponding variation of 14, which would give us 40º T.
Why 47º T?
