The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

87° W, deviation 14° easterly, what is the compass course? Cor. Mag. Course 87° L of N Dev. Ely (+) ido (exceeds 90°) to1° L of N 180° ---------- 79° R of S=W by S The correct magnetic coufse is S 8° Compass Course TAE Marine REVIEW which in reality is the true course first sought. It is possible to do this in a steam- boat and a sailing vessel with a fair wind when running' on ay straight course. When the true course has been corrected for Vat. and Dev: the result is the compass course and it is the course to be steered in order to make good Bo 2 oF Cours [a | AS he oe ST | ALS co CO : \ eee ase > \ DX oN \ » Or 5 OS Cc? of SAC TRUE COMPASS a _" \\\ pn Hil, nN \\\ wt : to Vd a Nyy 2 20 de My ON. : wry My 8 a Le i M WY eat Omp "Wy SR ANA 2 by, S ' io TY, Sa ° ab Le SS < i » x o © AZ, =< SN KOO yo oo SEN Ory Fs BE, iS ow . an Zz os oe = pe ee So et Z Sony e ae =i ao ee Sa eg 8S SS cis > i = Ss iS ce 25 SS oS 2 oo or « 2 Ss Ge s Updo) oS SS ae : oS Ze" YRS "je x y . \ 10 ay S Lh, 2 20 SY Ly, ag faba jas Saw "aps 1), / oS Uy Jo ih a | } | | \ \ \\\ ' 8 Ws My} fel pitts a \\ Inf? "thin bi] crane Var. Showing true compass, Var. compass and Dev. compass. is 6 degrees Wly. and Dey. 10 degrees Wly. W Dev. 16° Ely. Cor. Mag. Course, 8°' R of S Dev. (--) 164, Compass course E _. Here the deviation exceeds the amount of the course, therefore, the 8° Lof T=S % course is subtracted from the Dev. and. and reckoned the other from south. _ Correct the Course in the First Place. Note.--The correct magnetic course or bearing, when possible, should be enrrected for Dev. beforehand to of: tain its compass course. First the Var. is applied to the true course to get the correct magnetic course, then the Dev. corresponding to this correct magnetic course must be found from the table of deviations, or the curve of deviations, belonging to that particular compass, and the amount, whatever it is, applied to the correct course to obtain the compass course, way, magnetic the given true course because these corrections have been allowed for and got rid of. Sometimes it is necessary to convert a compass course (after the course has . been run) to a true course. For. in- stance, a sailing vessel with a head wind, making a zig-zag course, or a steam vessel when hauled off her course to favor the wind and sea. In either case the compass course has to be changed to a true course in order to find the true course that the vessel has been making good as:well as the vessel's position on the chart. It must be apparent that the course cannot in the first place be corrected in a case of this kind because the steering and' the course are controlled by the wind. The conversion of compass course to correct magnetic course is the reverse of correct magnetic course to compass course; the rule is: Ely. Dev. to the right and Wly. Dev. to the left of the correct magnetic ta Why. 31 course; or the same way that the Var. is applied in converting a correct mag- netic course to a true course, in fact there is the same relationship existing between these courses, they being first cousins, For an example, we will suppose that a sailing vessel is put close to the wind; her compass says she is sailing NE, and she keeps on this course for: an indefinite length of time, the Var. for the run being 6° Ely., and the Dev. on NE is 5° Ely., what. is the true course the vessel has been making over the ground? Compass Course NE = 40° R of .N Dev. Ely (+) Ot Cor. Mag. Course ci ROE WN Var, Ely, Cp) 5 True Course 50° R of N == NE by &. Here the. Var. oe Dev. 'are of the same name, both being Ely, making the total cosrection (Vat. and- Dey. combined) 11° Ely. Although the ves- sel has been steering NE by compass she has really been steering one point to the right of the course shown by compass, or NE by E. . If it were desired to steer a true NE course with the wind fair, under the same conditions, the vessel would have to steer NE a AG thus: True Course NEG s. S45 Rook WN Vat. Wives ae Cor. Mag. Course... ..; 40, Roof N Dev. Hiv. ii i. -- 6 L Compass Course:......, 34° Roof N = [NE by N (nearly.) The compass course is S by E, and the Dev. on this course is 34 point Ely. What is the correct agnsey course? Compass course S by ae =1 . pt. L of S. : Deviation Ely: ...2....,. 3% pt. R Correct Magnetic course.. Th pt. 1 of S=SYE The compass course is E Vy, S; dev- iation on this heading being iy points Wly. What is the correct magnetic course? : : ; Compass | course..E %45 = 7% pts. L [of S. Dev. Wig... 6 1% pts. L. Correct Magnetic course 9 pts. L Loft S: 16 7 opis [of N= E by N. The compass course is N % E: Dev. What is the corresponding correct magnetic course? Compass course N'%4E=N6°E