Exam Year:2015

DIPLOMA IN NAUTICAL SCIENCE
MODULE II
NAVIGATION I

SECTION A: CELESTIAL NAVIGATION

Answer any TWO questions from this section

1. (a) With the aid of a labeled sketch, explain the earth’s elliptical orbit showing aphelion,
Perphelion and the equinoxes. (8 marks)
(b) Explain each of the following terminologies as used in celestial navigation:
(i) celestial poles;
(ii) celestial meridian;
(iii) equinoctical;
(iv) oblique of the elliptic. (8 marks)
(c) Differentiate between SHA and GHA. (4 marks)
2. (a) With the aid of a labeled sketch, explain three terminologies associated with Celestial system of co-ordinates. (8 marks)
(b) Differentiate between ”zone times” and ”standard times”. (6 marks)
(c) Highlight three types of information obtained on the daily pages of a
Nautical Almanac (6 marks)
3. (a) With the aid of a sketch, indicate six stars found in ”URSA MAJOR”. (6 marks)
(b) Explain the relationship between the altitude of Polaris and the
Observers altitude. (4 marks)
(c) (i) Explain the ‘intercept method’ of calculating observers position on earth (4 marks)
(ii) List four parts of sextant. (2 marks)
(iii) With the aid if a labeled sketch, show how to find sextant index error using the diameter of a sun. (4 marks)

SECTION B: ELECTRONIC NAVIGATION SYSTEM AND MARINE INSTRUMENTS
Answer any THREE questions from this section

4. (a) With the aid of sketch , explain the principles of speed measurement using the ‘doppler
effect’ (8 marks)
(b) (i) Differentiate between continuous wave mode (cw) transmission and pulse mode
operation in depth sounding. (6 marks)
(ii) List six factors that affect the accuracy of speed logs. (6 marks)
5. (a) With the aid of a labeled sketch, highlight the basic principle of marine echo
sounder(14 marks)
(b) List six controls found on an echo sounder receiver panel (6 marks)
6. (a) Explain the process of using ‘Ras Serani’ transit to get compass error
(b) (i) With the aid of a labeled sketch , indicate true, magnetic and compass north.(6 marks)
(ii)differentiate between deviation and variation and highlight the mnemonics of remembering each
7. (a) Explain the function of each of the following manual settings applied when setting auto
pilot steering :
i. Permanent helm
ii. Rudder control
iii. Counter rudder
iv. Weather control (8 marks)
(b) (i) Highlight four factors to be considered while changing over auto steering from manual to automatic steering and vice versa
(ii)list four modes used in steering.(4 marks)
8. (a) With the aid of a labeled sketch , illustrate the basic concept ‘AIS’ automatic
identification system. (8 marks)
(b) List six data included in ships AIS data information. (6 marks)
(c) Explain the general IMO PERFORMANCE standards required of VDR(Voice Data
Recorder) on board ship.(6 marks)

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