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WorksheetsIlmu Pelayaran Datar 1 Gabungan
Total questions: 35
Worksheet time: 8mins
The equation of time is 8m 40s. The apparent Sun is ahead of the 1. mean Sun. If you are on the central meridian of your time zone, the apparent Sun will cross your meridian at?
11-51-25 ZT
11-52-20 ZT
11-51-20 ZT
11-52-25 ZT
What is the shortest distance between two points on the surface of the earth?
all the bearing
all the direction
all the above
Great Circle
Which nautical charts are intended for coastwise navigation outside of outlying reefs and shoals?
Nautical Almanac
General charts
Wind Direction
Reduction Tide Table
The climatic conditions formed in the area between latitudes 23.5° N and 23.5° S are?
Arctic
Polarized
Tropical
Equatorial
Winds that blow around curved isobars without experiencing friction and the earth's surface is?
Gradient wind
Fixed wind
Monsoons
trade wind
In the following conversion what is the value of 2 Cables = ......
27.5 m
185.2 m
370.4 m
1852 m
What is the ZT if your longitude 121°45 E ?
+12 GMT
+11 GMT
+8 GMT
+10 GMT
In the following conversion what is the value of 1 NM =…
1582 m
1852 m
1882 m
1552 m
What the meaning of small cirle on earth ?
geographic coordinate that specifies the north–south position of a point on the Earths surface
A circle on a sphere whose plane passes through the center of the sphere
A circle whose plane pass through the center of the sphere
A geographic coordinate that specifies the east–west position of a point on the Earths surface, or the surface of a celestial body
What is the actual shape of the earth?
oblate spheroid
rectangle
rectangle
perfect ball
What the meaning of Great circle ?
A circle on a sphere whose plane passes through the center of the sphere
A geographic coordinate that specifies the east–west position of a point on the Earths surface, or the surface of a celestial body
A circle whose plane pass through the center of the sphere
geographic coordinate that specifies the north–south position of a point on the Earths surface
How often is the chart catalog published
Twice a year
Weekly
Every year
Monthly
What is the shortest distance between two points on the surface of the Earth?
Small circle
Rhumb line
Composite great circle
Great Circle
What the meaning of Longitude ?
a circle whose plane pass through the center of the sphere
a geographic coordinate that specifies the east–west position of a point on the Earth's surface, or the surface of a celestial body
a geographic coordinate that specifies the north–south position of a point on the Earth's surface
a circle on a sphere whose plane passes through the center of the sphere
The Officer of the Watch intends to measure the distance on a Mercator chart at latitude 30° South. Which scale must be used?
Longitude scale
Latitude scale printed on the port and starboard margins of the chart
Upper longitude scale
Diagram and legend scale
The OOW needs to update a nautical chart that already contains numerous small corrections from the Notice to Mariners (NtM). What is the correct procedure?
Remove all small corrections
Request the chart to be reprinted
Insert the large correction which supersedes all previous small corrections
Ignore the corrections due to excessive number
A navigator wants to determine the elevation of an island shown on the chart. Where should this information be obtained?
Depth figures in fathoms
Figures enclosed in brackets located near the island
Tidal information table
Chart legend
Consider the following statements:
1. The rhumb line appears as a straight line.
2. Meridians are drawn parallel to each other.
3. Parallels intersect meridians at right angles.
4. Longitude scale increases with latitude.
Which of the above is NOT a characteristic of the Mercator projection?
1
2
3
4
A navigator cannot use longitude to measure distance on a Mercator chart. What is the reason?
The longitude scale varies with latitude
The longitude scale remains constant and therefore is unsuitable for distance measurement
The latitude scale is too small
Longitude values are only used on weather charts
A chart shows depths in meters, bears a Notice to Mariners reference dated 2024, and one of the updates is marked with the letter (T). What does this indicate?
A permanent correction
A preliminary correction
A temporary correction
An outdated correction
A Mercator chart displays the ship’s rhumb-line track as a straight line. However, the navigator aims to follow the shortest route between two positions. Is the Mercator chart suitable for this purpose?
Yes, because the rhumb line is the shortest distance
Yes, but only in low latitudes
No, because the great-circle track represents the shortest distance
No, because straight-line plotting is impossible on Mercator charts
Two charts are available:
– An older edition with complete small corrections
– A newly issued edition without small corrections
Which chart should the navigator select for safe navigation?
The older edition because it has more details
The new edition because it includes a full large correction
The older edition because it is more reliable
Either one can be used
An OOW evaluates a large-scale chart that has not been corrected for more than three years. What is the safest judgment?
Use the chart without concern
Rely on scale alone; the chart is accurate
Avoid using the chart due to the high risk of obsolete information
Combine the chart with Google Earth for corrections
According to SOLAS Chapter V Regulation 19-2, ships required to be fitted with ECDIS must comply beginning from …
1 January 2009
1 July 2010
1 July 2012
1 July 2020
One of the main operational functions of ECDIS onboard a vessel is to …
replace the gyrocompass system
assist voyage planning and route monitoring
measure engine performance
control ship stability calculations
In ECDIS, one degree of latitude and longitude is displayed primarily based on which geodetic datum?
Tokyo Datum
ED-50
WGS-72
WGS-84
Why is an ECDIS system operating with ENC data considered a “true ECDIS” compared to one operating with RNC data?
ENC charts use scanned paper charts
ENC charts allow automatic alarms and safety contour functions
RNC charts cannot display vessel position
RNC charts use larger memory capacity
Which comparison correctly distinguishes Vector Charts (ENC) from Raster Charts (RNC)?
ENC is pixel-based, RNC is object-based
ENC loses quality when zoomed in
RNC allows automatic danger alarms
ENC stores chart data as coded objects
When a vessel approaches shallow water, ECDIS can provide a safety warning primarily because …
ECDIS uses manual plotting
ENC supports safety contour and alarm parameters
RNC data updates faster than ENC
paper chart symbols are embedded in the system
The replacement of paper charts with ECDIS on SOLAS vessels is BEST justified because ECDIS …
entirely eliminates the need for navigator skills
guarantees zero navigational risk
provides continuous monitoring and automatic safety alarms
makes radar equipment unnecessary
Which condition would make ECDIS NON-COMPLIANT with SOLAS requirements?
The chart display uses ENC with valid updates
The ECDIS alarms are properly configured
ENC license has expired and charts cannot be corrected
Redundant sensors are connected
From a navigational safety perspective, which statement BEST evaluates the limitation of RNC use in ECDIS?
RNC charts are difficult to read
RNC charts cannot be used on IMO-approved ECDIS
RNC charts do not support automatic danger alarms
RNC charts do not show coastline information
Mean Sea Level (MSL) is determined based on tidal observations over a standard period of …
5 years
10 years
18.6 years
28 years
When a nautical chart uses Lowest Astronomical Tide (LAT) as its chart datum, the main practical advantage for a navigator is to …
improve chart readability
provide the maximum safety margin for depth clearance
speed up distance calculations
simplify current prediction
Evaluate the following statement:
“International datum standardization has little impact on the safety of international navigation.”
The most appropriate assessment is that the statement is …
correct, because ships rely on automated navigation systems
correct, because datum differences are easily corrected
incorrect, because inconsistent datums can lead to position errors and navigational accidents
incorrect, but only in port waters
