Navigation Flashcards
what is navigation?
Navigation is the science of maneuvering and monitoring a vessel from one place to another safely and efficiently
what are the two types of navigational charts?
Raster charts and Vector charts
What is the difference between raster and vector?
Raster charts are scanned copy of paper charts and vector charts are computer generated charts
What are 4 navigational equipment found on board?
AIS, RADAR, GPS, ECDIS
Whats is AIS and its purpose?
stands for automatic identification system. Used by seafarers to identify other vessels and monitor their positions. providing information like their location, speed and even heading
What is GPS and what is it’s purpose?
stands for global positioning system. It shows us our up to date location (lat and long) via satellite.
What is ECDIS and what is its purpose?
Stands for electronic chart display and information system. Is a navigational tool used by seafarers in order to plan and create routes, create safety measures and monitor our vessel’s movement. It simplifies navigational tasks
What is RADAR and its function?
Stands for radio detection and ranging. It sends out radio waves to locate targets and identify their bearing, distance and even speed
Three types of navigation
Terrestrial, Celestial, electronic
What is celestial Navigation?
Is navigation by the use of celestial bodies as reference. Bodies such as moon, sun and even constellations.
What is terrestrial navigation?
Terrestrial Navigation is navigation using terrestrial object as reference. Terrestrial bodies such as, buoys, light house and islands
What is electronic navigation?
Electronic navigation is the easiest of the three. It uses Electronic navigational tools in order to navigate. It easier do to the fact that it is computer generated
What is the difference between SOG and STW?
Speed overground is the speed of a vessel relative to the Earth’s surface without factoring in external forces
Speed through water is the speed of a vessel relative to the water factoring in external forces
It is possible for the SOG to be 0 and STW to be 3.
If a vessel is being pushed by the current for 3 knots, it’s STW would be 3, but SOG would be 0
What is bearing?
Bearing is the direction of the target measured in degrees
What is Horizon?
it is the imaginary horizontal line in which the earth and the sky meet
What are the 4 cardinal Marks?
North, East, South, West
What are the inter cardinal marks?
Northeast, northwest, Southeast, southwest
How many points in boxing the compass?
32 points each 11.25 degrees
What is latitude and longitude?
Latitude is the imaginary horizontal line that runs from the east of the earth to the west measured in 0 to 90 degrees
Longitude is the imaginary Vertical Line that runs from north to south of the earth. Measured from 0 to 180 degrees
What is compass error?
It is the difference between the compass heading and the true north
What are the 2 types of compass errors?
Variation and deviation
What is variation?
Variation is a compass error in which the compass points away from the true north because of the magnetic north’s influence
what is the formula from true to compass error?
T
V
M
D
C
E-
What is the formula from compass error to true?
C
D
M
V
T
E+
How to determine speed, distance, and time of a vessel?
Distance = SxT
S= D/T
T= D/S
what is dead reckoning?
Dead reckoning is locating our current position by the use of a known starting position and factoring in the direction the traveled, Elapsed Time and estimated speed
What is Set and Drift?
Set is the direction in which the current is pushing the vessel.
Drift is the speed in which the current is pushing the vessel
Nautical Mile to meters
1852 Meters
Nautical Mile to Kilometer
1.852
Mile to nautical mile
1.15 Miles
Kilometers to mile
0.6 miles
miles to kilometers
1.6 Kilometers
What is echo sounding?
using sound waves to determine the depth of the ocean and to locate what’s underneath
what is great circle?
Is the shortest distance from point A to Point B in shpere
What is voyage planning?
it is the procedure in creating a complete description of a vessel’s voyage start to finish
4 steps in voyage planning?
1 appraisal
2 Planning
3 Execution
4 Monitoring
What is the appraisal stage?
It is gathering essential information’s and documents for the vessels voyage
What is the planning stage?
you use the information that you have gathered to create a guide map for your voyage. that includes the shortest distance, the safest routes and the estimated time of arrival
what is the execution stage?
It is when you take your planning into action.
what is monitoring stage?
It is when you watch Monitor your vessel’s movements and make sure that the vessel is following the plan that you have made. also checking any available means to make sure that your vessel is in safe distance from hazards
two types of RADAR
S band and X band
difference between s band and x band
s band 2-4 hrtz better in bad weather, less detailed, longer wavelength
x band 8 - 12 hrtz better locating smaller objects and is more detailed, shorter wavelength
