Naval Skills, Unit Four, Chapter One: Introduction to Navigation
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The art and science by which mariners find a ship's position and guide it safely from one point to another.
Navigation
Sextant
Dead Reckoning
Course
Bearing
What is the name of the imaginary line that runs around the Earth, cutting every meridian in half?
The Equator
The International Date Line
The Prime Meridian
The Great Circle
The Parallel
Lines that divide the globe into two equal parts, or hemispheres, are called what?
Great Circles
Parallels
Meridians
Equators
Prime Meridians
What is the shortest distance of travel between two points on the Earth (or any globe)?
A great circle
A straight line
The equator
A parallel
A meridian
How many nautical miles would there be in three degrees, 20 minutes of latitude?
200 NM
20 NM
3.2 NM
320 NM
You measure distance from degrees of longitude, not latitude.
How many seconds of arc are in one degree of arc?
1,200
120
100
1000
60
What is the other common name for the Greenwich meridian?
The Prime Meridian
The International Date Line
The Royal Observatory Meridian
The Equator
The Great Circle
What is the name commonly given to the 180th meridian?
The International Date Line
The Greenwich Meridian
The Prime Meridian
The Equator
The Great Circle
Which of the headings below is NOT considered a cardinal point?
200 degrees
90 degrees
180 degrees
270 degrees
000 degrees
The direction a ship is facing is called it's ________. The direction it is moving through the water is it's ___________.
Heading, Course
Course, Heading
Bearing, Course
Heading, Bearing
Heading, Variation
What is the name of the instrument common on larger ships which always points toward true north?
A gyrocompass
A sextant
A meridian
A parallel
A cartographer
Where can you find the Earth's northernmost magnetic pole?
In northern Canada
In central Greenland
In northern Alaska
In north-central Russia
Along the Canadian-Alaskan border.
The angular difference between true north and magnetic north is known as what?
The Variation Angle
The Distortion Angle
The Relative Bearing
The Magnetic Bearing
The Mercator Angle
If your ship was heading 090 degrees magnetic in a region where the variation was 20 degrees East, what would the true heading be?
110 degrees true
090 degrees magnetic
070 degrees true
090 degrees true
110 degrees magnetic
Which of the following is NOT one of the standard ways of determining the direction of an object from an observer?
A visual range
True bearing
Magnetic bearing
Relative bearing
These are all valid methods of determining the direction of an object from an observer.
Which direction below would most closely relate to the starboard beam?
090 degrees
000 degrees
045 degrees
270 degrees
135 degrees
Which of the following is NOT an example of hydrographic information found on nautical charts?
Mean sea level elevations
Water depth
Overhead obstructions
Navigational aids
Anchorages
What is the common name given to map and chart makers?
Cartographers
Mercators
Navigators
Oceanographers
Sextants
Where is the greatest degree of distortion on a Mercator projection?
The farther away from the Equator you move.
The North Pole
The South Pole
The Equator
The International Date Line
Choose a correct combination for the following sentence describing the scale of a chart: "The _______ the ratio, the _____ the scale of a chart."
Smaller, Smaller
Smaller, Larger
Larger, Smaller
More northerly, more southerly
More southerly, more northerly
What type of charts are small-scale charts showing the approaches to large areas of the coast?
General ocean sailing charts
Harbor charts
Coastal charts
Mercator charts
Orienteering charts
On nautical charts, what units are used to show the depth of water?
Feet, fathoms or meters.
Feet or fathoms only
Fathoms or meters only
Feet, inches and fathoms
Feet, yards and fathoms
Which of the following is a plotting instrument used for measuring chart distances along a suitable scale on a chart?
A Divider
A Plotter
A Protractor
A Compass Rose
A Parallel Ruler
What do you call the intersection of two or more lines of position (LOPs) obtained at the same time?
A fix position
A fix
A distance arc
A visual range
A stadimeter
What is the term used when two landmarks or navigation aids are observed in line one behind the other?
On a visual range
On a fix position
In a distance arc
Along a line of position
On a compass rose
What instrument determines the distance to an object optically using as a reference the distance to an object of known height such as a masthead on a ship?
A stadimeter
Radar
Sonar
A sextant
A compass rose
Which of the following is NOT a proper combination for obtaining a accurate fix?
A visual range
Two or more lines of bearing
A distance arc and a line of bearing
Two or more distance arcs
A visual range and a distance arc
What symbol is commonly used on nautical charts to plot a ship's estimated position?
A square
A circle
A triangle
A half-circle with a line below it
There is no symbol for an estimated position, only for DR positions and fixes.
What instrument determines the depth of water under the ship's keel?
A fathometer
A sextant
A stadimeter
A loran
SINS
When using radar for electronic navigation, what for of display scope is most often used?
The Plan Position Indicator (PPI)
The Direct Display Indicator (DDI)
The Expanded Display Indicator (EDI)
The Loran Display (LD)
The Global Positioning System (GPS) display
Which of the following is NOT one of the advantages of using radar for navigation?
It has a long-range capability.
It can be used at night and during periods of low visibility.
A fix can be obtained from a single object.
It is very accurate and rapid.
It can be used to locate and track storms.
Which term below describes a navigational system made up of radio signals broadcast by groups of land-based transmitting stations at known positions?
Loran
Radar
Sonar
GPS
SINS
What navigational aid is rapidly replacing the system of Loran transmitting stations?
GPS
Radar
Sonar
Sextants
Stadimeters
Which of the following statements concerning GPS system is FALSE?
GPS receivers are self-contained and do not require external signals to operate.
It uses about twenty-four operational satellites.
It can provide three-dimensional fix capability on land, sea and air.
It is accurate to at least 10 meters everywhere on Earth.
It first became fully operational in 1994.
What is the advantage of using "differential" GPS information?
It enhances accuracy of positional information down to plus or minus one meter.
It provides electronic time-of-day information as well as fix position information.
It makes navigational information available even when the receiver cannot "see" a minimum of three GPS satellites.
There is no advantage. Differential GPS is simply standard GPS information which has been reduced in accuracy so as not to help an enemy.
Differential GPS information can be used by submarines below the surface of the water.
Which navigational listed below is the only one that could not be jammed by an enemy in time of war?
SINS
GPS
Loran
Radar
Sonar
What do celestial navigation systems use to determine fix locations?
Heavenly bodies such as the Sun, Moon and selected stars and planets.
A constellation of 24 GPS satellites
Several Loran transmitters located throughout the world.
Celestial navigation systems do not require outside sources of reference. They are all self-contained systems.
Dead reckoning plots.
Determining a ship's position from the direction and distance traveled from a know starting point is known as what?