Mock Flashcards
Where does a gyroscope experience maximum tilt?
The equator
What does the second law of magnetism state?
The force between two poles varies directly as the product of their pole strengths and inversely as the distance between them
What is the viscosity of the liquid in the compass bowl selected to provide?
Good damping of the card movement
What is a pelorus?
A sighting device mounted on a 360 degree graduated plate with 0 degree graduation aligned with the ship’s fore and aft line
What rods relate to coefficient D?
a and e rods
Force P causes the compass deviation to vary in accordance with which curve?
Sin curve
Force P is the athwartship component of a ship’s induced magnetic field. True or false?
False
What influences the drift of a gyroscope?
Rotation of the Earth and Latitude of the ship
What are the foci of magnetic lines of force called?
The poles of the magnet
Force Q is which component of a ship’s permanent magnetic field?
Athwartship
Is damping error integral to a gyro damped in azimuth?
No
What maintenance is carried out on a Fibre Optic Gyro?
Cleaning with a clean cloth
Should any accidental movement of the correctors in the binnacle be left until the next compass correction?
No
What is ballistic deflection caused by?
Precession that results from a surge in the liquid ballistics
Heeling error is the largest at which headings?
North and South
What does the first law of magnetism state?
That like poles repel each other and unlike poles attract each other
What does k rod represent?
Vertical soft iron that has its effective pole directly below the compass
What is variation?
The name given to an angle between the Magnetic and True Meridian of the Earth
Damping error can be approximated to what?
1.5TanLat
A gyro axis tilts upwards at the rate of approximately how many degrees per hour?
15
What path does the axis of a gravity controlled gyro follow?
Elliptical
The composition of hard iron is such that once magnetised it will retain that magnetism. True or false?
True
A gyroscope spin axis would experience tilt and drift at Latitudes other than the equator. True or false?
True
What does the damping of a gyroscope spin axis refer to?
Restricting the movement of a spin axis
On modern gyrocompasses the Speed, Course & Latitude error is calculated using manual or GPS inputs. True or false?
True
Coefficient D is corrected using what?
Quadrantal correctors
Where would speed, course and latitude error be high?
Courses with North component
Coefficient C is corrected using what?
Athwartships permanent magnets
A fibre-optic gyrocompass relies entirely on the stability of the speed of light in a vacuum. True or false?
False
Force Q causes the compass deviation to vary in accordance with which curve?
Cos curve
The c rod represents horizontal soft iron that has its effective pole in the same fore and aft line as the compass. True or false.
False
What are the components of gyroscopic inertia?
Tilt and drift
A gravity-controlled gyroscope may have a pair of Mercury pots attached with a fine bore tube. True or false.
True
The output from a fibre-optic gyrocompass can include what?
Rate-of-turn
Roll and pitch
Heading
What relates to coefficient B?
Force P and c rod
A free gyroscope has what (3)?
Spin axis, three degrees of freedom of movement, a well-balanced rotor
What force relates to coefficient C?
Force Q
What is induced magnetism collectively referred to as?
Rod-effects
