3832

THE NEW ZEALAND GAZETTE.

[No. 87

5. A beacon, 45 ft. high, subtends a vertical sextant angle of 1° 10'.
   After steering 3 miles it was observed to be abeam. What
   vertical angle would it subtend after steaming a further 2½
   miles on the same course?
6. What is meant by a Sidereal Day and how is the length of a
   Sidereal Day determined?
7. Show clearly how the sum or difference of the Meridian Zenith
   Distance of a Heavenly Body and its declination is equal to
   the Latitude of an Observer.
8. Enumerate and explain the corrections to be applied to an
   observed sextant angle.
9. Having been given a definite scale of Latitude for a Mercator
   Chart, explain fully how you could then draw up a scale of
   Longitude.
10. Draw a figure and trace the changes in the sign and magnitude
    of the Sine, Cosine, and Tangent of an angle as it increases
    from 0° to 180°.
11. In Latitude 48° N., on March 7th, 1929, what will be the hour
    angle of the star α Leonis (Regulus) when its altitude is 37°?
12. State fully what you know of the Earth's orbit.

PRACTICAL NAVIGATION I.

Paper 2 (2 hours).

1. The Pile Lighthouse off Belfast is charted as 40 ft. high. How
   high above sea-level would this lighthouse be on 10th November,
   1929, at 19h. 00m. standard time. M.H.W.S. 11·1 ft.
2. The departure position being in Lat. 32° S., Long. 33° W., a steamer
   makes the following true courses and distances : West 310 miles,
   South 410 miles, East 310 miles. Find the position arrived at.
3. Find, by Mercator's Sailing, the true course and distance from A
   in Lat. 43° 25' S., Long. 149° 02' E., to B in Lat. 40° 20' S.,
   Long. 172° 22' E.; and give also the compass course to steer
   if the variation is 10° 30' E. and the Deviation is 17° 40' W.
4. What effect has temperature upon chronometers and why is the
   temperature an important factor when chronometers are being
   compared?
5. Chronometer A is 10m. 33s. fast of B. B is 29m. 17s. slow of C. If
   C is 29m. 18s. fast of G.M.T., find A's error on G.M.T.
6. On 17th December, 1929, the position by D.R. being Lat. 39° 50'
   S., Long. 2° 06' W., the star β Canis Majoris (Mirzam) bore
   East by compass, the correct G.M.T. being 22h. 04m. 39s.
   Find the true bearing of the star and thence the error and
   deviation of the compass, the variation being 28° W.

PRACTICAL NAVIGATION II.

Paper 3 (3 hours).

1. From the following data find the position of the ship by D.R.
   at 9 p.m.
   (1) 2h. 15m. p.m. Tuskar Rock (Lat. 52° 12' N., Long.
   6° 12' 20" W.) bore N. 70° W., compass (Dev. 4° W.,
   Var. 16° W.), Dist. 7 miles ship's head S. 20 W., Log 25.
   (2) 3h. 00m. p.m. Course altered S. 70° W. (Dev. 6° W.,
   Var. 16° W.), Log 33.
   (3) 4h. 00m. p.m. Course altered S. 72° W. (Dev. 6° W.,
   Var. 16° W.), Log 44.
   (4) 9h. 00m. p.m., Log 100.
2. On 10th June, 1929, at 00h. 38m. (M.T.S. approx.), in Lat. 39°
   40' N., Long. 41° 06' W., by D.R., the observed meridian
   altitude of Saturn was 28° 11' bearing South. Index error
   01' +; Height of eye, 42 ft.
   Find the latitude and position line.
3. On 30th June, 1929, at about 12h. 25m. p.m., the D.R. position
   of the ship being Lat. 39° 30' S., Long. 100° 13' W., the observed
   altitude of the sun's L.L. was 26° 59'. Time by chronometer
   was 19h. 19m. 00s., being 7m. 25s. fast of G.M.T. Sextant
   error, 2' 20" +; Height of eye, 45 ft.
   Find the Latitude and the position line.
4. On 3rd November, 1929, at about 09h. 45m. a.m., the D.R. position
   being Lat. 51° N., Long. 12° W., the following observations
   were made : Obs. Alt. Sun's L.L. 17° 48'; G.M.T. 10h. 21m.
   29s.; Sextant error, nil ; Height of eye, 26 ft.
   Find the position line upon which the ship is situated.