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MIDDLE LATITUDE SAILING BY INSPECTION

Dif. lat. 122'.7 S.L
Dep. 168.0 E.

= Co. S. 54° E. dist. 208'.

Lat. Fire I. L. 40° 37' 57" N. Long. Fire I. L. 73° 13'08" W. Dif. 122.7=- 2 02 42 S. Dif. 217'.5=- 3 37 30 E. Lat. ship 38 35 15 N. Long. ship 69 35 38 W. Lat. Fire I. L. 40° 37' 57" N. Lat. ship + 38 35 15 N.

2)79 13 12 Middle lat. = 39 36 36 Middle lat. 39° 1/2 dep. 168'.o= dif. long. 217'.5= 3° 37' 30" E.

MERCATOR SAILING BY INSPECTION

2498.3 - 2373.6

124.7 S.

Lat. ship 38° 35' 15" N. Mer. parts
Lat. Cape H. – 36 55 35 N. Mer. parts
Dif. 99'.7= I 39 40 S. Dif.
Long. ship – 69° 35' 38" W.
Long. Cape Henry 76 00 27 W.
Dif. 384.8= 6 24 49 W.
Mer. dif. lat. 1247 S } = Co. S. 72° W.
Dif. long. 384.8 W.S
Co. S. 72° W.
Prop. dif. lat. 99'.7)

{= Distance 323'.

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Co. S. 72° 03' W. Prop. dif. lat.

sec.

99'.7 323.5

.51119 +1.99870 = 2.50989

Dist.

PRACTICAL DEAD RECKONING The traverse table is not used in the practice of navigation, but its use must be learned that more practical means may be used to keep account of a ship's track.

Usually the following method is not wanted at an examination, bụt should be used in practice. The former is quite satisfactory so far as the final result is concerned, which is not known until the end of the day. By this the ship’s position may be known at any moment. In other words, by one the ship takes the man and by the other the man takes the ship.

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Lat. Fire I.
Dif.
Lat. noon
Dif.
Lat. 4 P.M.
Dif.
Lat. 8 P.M.
Dif.
Lat. Mdt.
Dif.
Lat. 4 A.M.
Dif.
Lat. 8 A.M.
Dif.
Lat. noon
Dif. (current)
Lat. noon

40° 38'.0 N.

Long. Fire I.
9.9 S. = 40° dep. 3".6= dif. :
40 28.1 N.

Long. noon
15.1 N. =41 dep. 37.3= dif.
40 43.2 N.

· Long. 4 P.M.
_32.5 S. = 40 dep. 16.7 = dif.
40 10.7 N.

Long. 8 P.M.
8.7 S. = 40 dep. 37.5 = dif.
40 02.0 N.

Long. Mdt.
_39.4 S. = 40 dep. 1.7= dif.
39 22.6 N.

Long. 4 A.M.
36.9 S. = 39 dep. 42.8= dif.
38 45.7 N.

Long. 8 A.M.
27.9 S. = 39 dep. 57.2 = dif.
38 17.8 N.

Long. noon
+ 17.2 N. = 38 dep. 12.0= dif. (current)
38 35.0 N.

Long. noon

73° 13'.1 W.
+_ 4.7 W.

73 17.8 W.
- 49.4 E.

72 28.4 W.
+_21.8 W.

72 50.2 W.
- 49.0 E.

72 0I.2 W. -_ 2.2 E.

71 59.0 W.
- 55.8 E.

71 03.9 W.
- 1 13.6 E.

69 50.3 W.
– 15.2 E.

69 35 .1 W.

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The result is two noon positions, the first without considering the current, which in the other is taken into account.

The current could be considered on each course, but such a degree of precision is seldom necessary.

The ship's position differs slightly from that found by the preceding method, but is quite near enough to meet the demands of practice.

Lat. Fire I. 40° 38'.0 N. Long. Fire I. 73° 13'.1 W. Lat. ship

– 38 35,0 N. Long. ship - 69 35.1 W. Dif. 123.0= 2 03. S. Dif. 218'.= 3 38.0 E Mid. lat. 39°/2 dif. long. 218.0= dep. 168'.2

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