T-Nav Exam 2

Front 1

Apparent Solar Time-

Back 1

time based on the actual position of the sun at any given time

Front 2

Which fictitious sun do we keep time on that travels at a constant speed?

Back 2

Mean Sun

Front 3

The speed of travel of the "mean sun" is:

Back 3

15deg of longitude per hour of mean solar time

Front 4

Since the day has 24 hrs in it, then the sun must cover 360deg / 24 =

Back 4

15deg of longitude per hr

Front 5

Mean Solar Time is commonly called:

Back 5

"mean time"

Front 6

The Mean Time at any given location is called:

Back 6

"Local Mean Time"

Front 7

The Mean Time at Greenwich, England is called:

Back 7

"Greenwich Mean Time"

Front 8

The difference between mean solar time and apparent solar time at any given instant is called the:

Back 8

"Equation of Time"

Front 9

One day is:

Back 9

one complete rotation of the Earth on its axis

Front 10

At 0100, the Earth has rotated through:

Back 10

1/24 of 360deg, or 15deg of longitude

Front 11

1 Day (24 hrs) of Time =

Back 11

360deg of Arc

Front 12

1 Hour (60 mins) of Time=

Back 12

15deg of Arc

Front 13

4 minutes of Time =

Back 13

1deg = 60'

Front 14

1 minute of Time =

Back 14

15' of arc

Front 15

4 seconds of Time =

Back 15

1' = 60"

Front 16

1 second of Time =

Back 16

.25' = 15"

Front 17

Local Zone Time-

Back 17

when everyone in that particular area keeps the same time

Front 18

Time Zones are:

Back 18

15deg of longitude in width

Front 19

The Prime Meridian, or the Greenwich is the central meridian of the time zone whose Zone Description is:

Back 19

0

Front 20

Zone Description-

Back 20

indicates the difference from Greenwich Mean Time in hours

Front 21

Different Types of Currents:

Back 21

-Ocean currents
-Tidal currents
-Wind currents

Front 22

Ocean Current-

Back 22

a fairly stable, regular, well-defined current extending over a considerable distance

Front 23

Tidal Currents:

Back 23

-caused by the rise and fall of the tide

Front 24

Reversing Tidal Current-

Back 24

-when tide is rising in harbor, current is rushing into harbor
-when tide is falling in harbor, current is rushing out of harbor

Front 25

Along a coast line, a tidal current will usually be:

Back 25

rotary in nature

Front 26

Rotary Current-

Back 26

at any given location, the direction in which the current flows will change through all the points of the compass in one complete tidal cycle

Front 27

Wind Currents:

Back 27

-caused by the wind blowing steadily and strongly in the same direction for a considerable period of time, which usually means for 12 hrs or more
-affected by the "force of Coriolis"
-do not flow in exactly the same direction as that in which the wind is blowing

Front 28

The "force of Coriolis" is caused by:

Back 28

the rotation of the earth on its axis

Front 29

In the Northern hemisphere, the "force of coriolis" causes currents to be:

Back 29

-deflected to the right, or clockwise, from the direction in which the wind is blowing

Front 30

In the Southern hemisphere, the "force of coriolis" causes currents to be:

Back 30

deflected to the left, or counterclockwise.

Front 31

Wind Currents generally affect:

Back 31

small areas of ocean, and are temporary in nature

Front 32

Set of the Current-

Back 32

direction the current is flowing

Front 33

Drift of the Current-

Back 33

speed of the current

Front 34

Running Fix-

Back 34

a fix obtained by 2 observations, separated in time, on a single object

Front 35

Gulf Stream Current:

Back 35

-sets northward along the east coast of Florida
-very strong

Front 36

Yucatan Channel:

Back 36

-between the Yucatan Peninsula of Mexico and the western end of Cuba
-in center of channel, current sets northward as fast as 3-4 knots

Front 37

Special Case Bearings can be used to determine:

Back 37

-distance off when abeam
-distance off at the time of the second bearing

Front 38

Special Case Bearings:

Back 38

-Bow and Beam
-Double the Angle on the Bow
-7/10 Rule
-26.5deg - 45deg Rule