Gyro Compass

Question 1

2 basic principles:

Answer 1

Rigidity in space:
When a gyroscope is spinning and there are no external forces acting on it it will keep pointing in the same direction.

Precession:
Rotational movement perpendicular to applied force.
(Force applied to axis will move 90• to it)

Question 2

3 advantages & 3 disadvantages:

Answer 2

Advantages:
Not affected by variation & deviation
Multiple receivers possible
Can place them anywhere

Disadvantages:
Requires constant power
Expensive
Maintenance

Question 3

Operational checks:

(8)

Answer 3

Once per watch: Deviation

Routine testing

Power supply UPS

Calibration to True North

Cleaning & lubrication

Visual inspection (loose connections)

Mounting

Record keeping: calibration / maintenance

Question 4

3 methods of checking Gyro:

Answer 4

Transits

Amplitude of the sun

Azimuths of heavenly bodies

Question 5

Transit:

Answer 5

Visual bearings of transits

Compared to on chart using parallel rules

Question 6

Amplitude of the sun:

Answer 6

Latitude (from GPS)

Nautical almanac: Declination of day

Norries: Declination (top of table) Latitude (side of table)

Compare to compass reading for CE

Question 7

Azimuth of a heavenly body:

Answer 7

Bearing of the sun (time)

Find Greenwich Hour Angle + declination of sun

Work through chosen longitude and LHA

VOL. 1 or 2 of Sight reduction tables

Extract Azimuth (True bearing of the sun)

Compare Azimuth to compass bearing for CE