Navigation Instruments

Navigation instruments refers to instruments used by nautical navigators and pilots as instruments of their trade. The function of navigation is to determine the present positioning and to determine the velocity, direction etc. to arrive at the port or point of destination.

Charts and drafting instruments Charts  are maps of the areas to be navigated with details precise to the marine environment.

Computing aids: applied in the essential mathematical calculations. Nowadays electronic computers  or calculators  are applied. Remaining traditional aids used included tables (trigonometric, logarithms, etc.) and slide rules.

Chart Dividers applied for measuring lengths of lines and approximate lengths of non-linear courses on a chart.

Nautical almanac used to find the position in the sky of a celestial body after a sighting has been acquired.

Parallel rules for changing a line to a parallel position and  also used to compare the orientation of a line to a magnetic or geographical orientation on a compass rose.

Direct measuring

Chip log and sand glass  function to measure the ship's speed through the water.

Sounding line used to assess the depth of the water and to pick up samples from the bottom.

Position finding instruments

Celestial navigation instruments.

These instruments are applied in the first place to measure the elevation or altitude of a celestial object.

Back staff, the best recognized of which is the Davis' quadrant. It could measure the altitude of the sun without making the navigator directly observe the sun.

Cross staff, an aged navigation Instrument long out of use.

Kamal a very simple instrument applied primarily by Arab sailing master*. It consists of a small board with a knotted bit of string through the center. The observer takes hold one of the knots In is mouth and extends the board away in order that the edges make a constant angle with his eyes.

Mariner's astrolabe  Derived from the astrolabe, it was developed in late 15th century and found use in the sixteenth to seventeenth centuries. It was superseded by the back staff  and later by the octant  sextant

Quadrant  A very simple navigation Instrument which used a plumb bob.

These instruments are also used to measure the angular distance between objects:

Octant, contrived in 1731. The foremost widely-accepted instrument that could measure an angle without being strongly affected by movement.

Sextant, derived from the octant in 1757, finally caused all former instruments used for the same function outdated.

Bearing instruments

Pelorus  used to determine bearings relative to the ship's heading of landmarks, other ships, etc.


Bearing compass  used to specify magnetic bearings of landmarks, other ships or celestial bodies.

Magnetic compass used to find out the magnetic heading of the ship.

Marine Charts used to plot the vessels position.

Chart lights used for navigation at night to Illuminati the charts on the bridge.

Magnifying glass used to enhance the reading of nautical charts.

Brass telescope use for sighting other vessels and viewing the coast to assist in the fixing of the position of the ship.

The navigation Instruments here which do not have a link to another page of information are available for you to write your own content for these navigation Instruments.

The Study of Navigation Instruments 

Navigation is a area of study that focuses on the procedure of monitoring and controlling the apparent motion of a craft or vehicle from one place to another. The study of navigation includes four general-purpose categories: land navigation, nautical navigation, aeronautical navigation, and space navigation.

 It's also the term of art  applied for the specialized knowledge used by navigators  to execute navigation tasks. All navigational methods necessitate locating the navigator's positioning compared to known locations or patterns.

Navigation, in a more encompassing sense, can refer to any skill or study that calls for the determination of position and direction. In this sense, navigation includes orienteering  and pedestrian navigation. Navigator

A navigator is the individual on board a ship or aircraft responsible for its navigation. The navigator's principal responsibility is to be aware of ship or aircraft position at all times. Responsibilities include planning the journey, advising the Master  or aircraft Commander of calculated timing to destinations whilst en route, and seeing to it hazards are avoided. 

Aboard ships in the Merchant Marine  and Merchant Navy, British_Merchant_Navy, the Second Mate is generally senior Navigator

With the advent of GPS, the effort called for to precisely check one's position has decreased by orders of magnitude, so the entire discipline has experienced a revolutionary transition since the 1990s with time-honored navigation tasks being phased out due to navigation Instruments being superseded.

Time keeping

Marine chronometer  applied to check time at the prime meridian  with great precision which is essential when reducing sights in celestial navigation.

Nocturnal used to determine apparent local time by viewing the Polaris  and they're surrounding stars.

Ring dial  or astronomical ring used to measure the height of a celestial body above the horizon. 

It could be applied to find the altitude of the sun or find out local time. It let sunlight shine through with a little orifice upon the rim of the instrument. The point of light striking the far side of the instrument established the altitude or tell time.

All those named were the traditional navigation Instruments practiced until well into the second half of the twentieth century. After WWII electronic aids to navigation evolved really quickly and, to a great extent, superseded more traditional tools. Electronic speed and depth finders have totally replaced their older counterparts. Radar has become widespread even in little boats. A few Electronic aids to navigation like LORAN have already become outdated themselves and have been superseded by and replaced by GPS.

The navigation Instruments here which do not have a link to another page of information are available for you to write your own content for these navigation Instruments and write about your navigational experiences during your sea career, inspiration makes mariners, pay it forward.

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