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

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

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.

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

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

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

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 4W 045C 032 041M

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 283 (True Bearing to Vessel)

Navigation Study Guide P2-7 through P2-16: Variation = 015E . T V M D C 15E P2-7 T V M D C 15E 035C 055 040M 5E P2-8 T V M D C 15E 135C 149 134M 1W P2-9 T V M D C 149 15E 134M 1W 135C 035R 184 (True) Bearing to Buoy

Navigation Study Guide P2-10 T V M D C 15E 285C 297 282M 3W 090R 387 (Subtract 360) 027 (True) Lighthouse Bearing P2-11 T V M D C 027 15E +180 to find reciprocal 207 (True) Reciprocal Bearing T V M D C 207 15E 192M Reciprocal

Navigation Study Guide P2-12 T V M D C 15E 185C 196 181M 4W 285R 481 - 360 = 121: Bearing +180 (to find reciprocal) 301 (True) Reciprocal P2-13 T V M D C 110 15E 095M 3E 092C 285R Buoy “6” Bearing 002C <== 362C

Navigation Study Guide P2-14 T V M D C 200 15E 185M 4W 189C P2-15 T V M D C 15E 145C 158 143M 2W P2-16 T V M D C 15E 323C 338 323M 0 End of Problems