1. Navigation Study Guide
Chapter 2: Compass
Instructor: Forrest Meiere
Selected Questions: Study these for exam
PowerPoint Presentation
by Forrest Meiere

2. Navigation Study Guide
S2-4 Fastened to the gimbal is one or more
against which the dial graduations can be read to determine the direction of the vessel relative to the card.
Lubber's Lines
S2-6 During the mid-1920's an electronic compass termed a compass was developed for aircraft. In recent years, this has become available to the mariner.
fluxgate

3. Navigation Study Guide
S2-7 The modern magnetic compass is highly sensitive and is able to align itself with , such as the earth's magnetic field.
weak magnetic fields
S2-8 However, the magnetic field aboard a vessel is not solely due to the earth's magnetic field. Other shipboard magnetic fields are caused by a variety of items, including .
see list in book
No need to memorize this list, just recognize some of the items if presented in this context.

4. Navigation Study Guide
S2-9 These additional fields also affect the compass, with the result that the of the vessel may differ from its
compass heading
magnetic heading
S2-10 Simply put, is the difference between the direction that the compass actually points and the direction that it would point if there were no local magnetic fields aboard the vessel.
deviation
S2-12 Unlike variation, which depends solely on the vessel's position, deviation varies with the vessel's
heading

5. Navigation Study Guide
S2-15 A device for measuring relative bearings is termed a
pelorus
S2-16 The letter sequence TVMDC is used to describe the sequence of starting with a course, correcting for
__________ to calculate a course, and finally allowing for to calculate a course.
True
Variation Magnetic
Deviation Compass
S2-17 When converting from a true course to a compass course (i.e. uncorrecting), westerly variation and deviation are to be
added

6. Navigation Study Guide
S2-18 When converting from a compass to a true course (correcting), variation and deviation are to be
and variation and deviation are to be subtracted.
East added
West
S2-19 It is important to remember that compass readings are most accurate only when the vessel is level,
, and maintaining a constant course..
traveling
at a constant speed
No need to memorize these constraints or the corrections in S2-19 & S2-20; just recognize them in a question
End of Questions

7. Navigation Study Guide
P2-1: T V M D C
29W 287C
258M
P2-2: T V M D C
060M 056C 4E
P2-3: T V M D C
9W W 045C M

8. Navigation Study Guide
P2-4: T V M D C
013 9W
022M
P2-5: T V M D C
022M 4E
018C
P2-6: T V M D C
013 9W 022M 4E 018C
270R
(True Bearing to Vessel)

9. Navigation Study Guide
P2-7 through P2-16: Variation = 015E
T V M D C
15E
P T V M D C
15E 035C
M 5E
P T V M D C
15E 135C
M 1W
P T V M D C
149 15E M 1W 135C
035R
184 (True) Bearing to Buoy

10. Navigation Study Guide
P T V M D C
15E 285C
M 3W
090R
(Subtract 360)
027 (True) Lighthouse Bearing
P T V M D C
027 15E
+180 to find reciprocal
207 (True) Reciprocal Bearing
T V M D C
207 15E
192M Reciprocal

11. Navigation Study Guide
P T V M D C
15E 185C
M 4W
285R
= 121: Bearing
+180 (to find reciprocal)
301 (True) Reciprocal
P T V M D C
110 15E
095M 3E 092C
285R
Buoy “6” Bearing 002C <== 362C

12. Navigation Study Guide
P T V M D C
200 15E
185M 4W 189C
P T V M D C
15E 145C
M 2W
P T V M D C
15E C M
End of Problems