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Gyro Compass On Ships: Construction, Working, And Usage
A Gyro compass is a form of gyroscope, used widely on ships. It employs an electrically powered, fast-spinning gyroscope wheel and frictional forces, among other factors, to find the true north, utilising the basic physical laws, influences of gravity, and the Earth’s rotation.
Construction of Gyro Compass
The marine gyro compass has become an indispensable instrument in almost all merchant ships and naval vessels, as it is capable of detecting true north rather than magnetic north. It is comprised of the following units:
- Master Compass: Discovers and maintains the true north reading with the help of a gyroscope
- Repeater Compasses: Receive and indicate the true direction transmitted electrically from the Master Compass.
- Course Recorder: Makes a continuous record of the manoeuvring on a moving strip of paper.
- Control Panel: Governs the electrical operation of the system and ascertains the running condition by means of a suitable meter.
- Voltage Regulator: Maintains a constant supply of power to the motor-generator.
- Alarm Unit: Indicates failure of the ship’s supply.
- Amplifier Panel: Controls the follow-up system.
- Motor Generator: Converts the ship’s DC supply to AC and energises the Compass equipment.
Gyro compasses are linked to the repeater compasses via one transmission system. The fast-spinning rotor attached weighs from 1.25 pounds to 55 pounds.
It is driven by thousands of revolutions per minute by another electric motor. However, the most essential part of a Gyro compass system is the spinning wheel, known as the Gyroscope.
Working of Gyro Compass
External magnetic fields which deflect normal compasses cannot affect Gyro compasses. When a ship alters its course, the independently driven framework called ‘Phantom’ moves with it, but the rotor system continues to point northward.
This lack of alignment enables it to send a signal to the driving motor, which moves the phantom step in with the rotor system again in a path where the phantom may have crossed only a fraction of a degree or several degrees of the compass circle.
As soon as they are aligned, electrical impulses are sent by the phantom to the repeater compasses for each degree it traverses.
The Gyroscope in the Gyrocompass is mounted in such a way that it can move freely about three mutually perpendicular axes and is controlled to enable its axis of spin to settle parallel with the true meridian, influenced by the Earth’s rotation and gravity.
The Gyrocompass system applications are based upon two fundamental characteristics, which are:
- Gyroscopic Inertia: The tendency of any revolving body to uphold its plane of rotation.
- Precession: A property that causes the gyroscope to move when a couple is applied. Instead of moving in the direction of the couple, it moves at right angles to the axis of the applied couple and the spinning wheel.
These two properties and Earth’s natural forces of rotation and gravity allow the Gyrocompass to seek true north.
Once settled on the true meridian, the rotor will indefinitely remain there as long as the electrical supply of the ship remains constant and unaffected by external forces.
Usage and Errors
Gyro compasses are preeminently used in most ships to detect true north, steer, find position and record courses.
But due to the ship’s course, speed and latitude, there could be some steaming errors. It has been found that on Northerly courses the Gyro compass north is slightly deflected to the West of the true meridian, whereas on Southerly courses it is deflected to the East.
Modern ships use a GPS system or other navigational aids to feed data to the Gyrocompass for correcting the error. An orthogonal triad of fibre optic design and ring laser gyroscopes, which apply the principles of optical path difference to determine the rate of rotation, instead of depending upon mechanical parts, may help eliminate flaws and detect true north.
You might also like to read-
- 10 Best Sundial Compass You Can Buy
- An Introduction to Fluxgate Compass
- 5 Maritime Technologies From 100 Years Ago That Still Work Today
Disclaimer :
The information on this website is for general purposes only. While efforts are made to ensure accuracy, we make no warranties of any kind regarding completeness, reliability, or suitability. Any reliance you place on such information is at your own risk. We are not liable for any loss or damage arising from the use of this website.
Disclaimer :
The information on this website is for general purposes only. While efforts are made to ensure accuracy, we make no warranties of any kind regarding completeness, reliability, or suitability. Any reliance you place on such information is at your own risk. We are not liable for any loss or damage arising from the use of this website.
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pleasehelp.compass with cover,like divers helmit, has veiwing glass init, electric light and oil lamp.cover comes off with half turn. beleav off american frigate
It is helpful as it is in plain language. I appreciate it.
can you please state the main systems under the control of the gyrocampass and explain it?
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As a ship moves from one side of the earth to the other, wouldn’t the gyroscope flip upside down? If it is indeed spinning to maintain angular momentum, the coronal, axial, and sagittal planes would remain the same. Even if the gyroscope were to remain in a fixed location (ship anchored at a port), the earth is rotating. If the earth rotates once, the gyroscope in the anchored ship should do a complete 360° flip.
Does anyone here have an explanation?
My ship staying at port/docking for a long time, do i have to take a gyro compass error in everyday?
Please advise!
Thanks
Brgds,
Nawir
How often must the course recorder be aligned with the gyro course? Why is this important and how is the alignment being recorded?
I have a compass that is heavy, round and has liquid in it. Can you tell me what it is called?
HOW IS THE TRANSMISSION EFFECTED FROM THE MASTER COMPASS TO THE REPEATERS?
@Corrine I believe that it is a magnetic compass
I would think the 360 applys,like a clock laying flat on the floor,not standing up right like on the wall.?
Is it possible to create a portable Gyrocompass as the one in ships is big and heavy?
El sistema giroscopico, inventado por Karl Anschutsx en 1912, sufrio variantrs tecnológicas a traves de los años, sumando mas giroscopos en su nucleo, y mejorando los sensores de campo. Las infimas desviaciones latitudinales (+/-0.05° en latitudes >70°) fueron compensadas mediante sistemas de control electronico, pero, toda esa tecnología murió a principios del siglo XXI, al crearse el giroscopio laser, que no utiliza partes moviles ni giroscopos. Es libre de mantenimiento y de desvios.