ASA 105 Coastal Navigation Exam V1 Practice Test
Actual 2025/2026 with Detailed Rationales | 100%
Verified | Pass Guaranteed – A+ Graded
Section 1: Coastal Navigation Fundamentals (Q1–Q12)
Q1: What is the distance represented by one minute of latitude?
A. 1 statute mile
B. 1 kilometer
C. 1 nautical mile [CORRECT]
D. 1,000 yards
Correct Answer: C
Rationale: One minute of latitude equals one nautical mile (approximately 6,076
feet), which is the standard unit of distance used in navigation.
Q2: On a nautical chart with a scale of 1:80,000, which feature would be most
accurately represented?
A. Oceanic current patterns
B. Detailed depth soundings in a small harbor
C. Coastal topography and medium-sized harbors [CORRECT]
D. Global weather systems
Correct Answer: C
Rationale: A 1:80,000 scale is a medium-scale chart suitable for coastal navigation,
showing coastal topography and medium harbors with adequate detail for inshore
passage.
Q3: When measuring distance on a Mercator projection chart, you should use the:
A. Longitude scale at the equator
B. Latitude scale at the approximate latitude of the measurement [CORRECT]
C. Chart's bar scale regardless of latitude
D. Longitude scale at the mid-meridian of the chart
Correct Answer: B
,Rationale: On a Mercator chart, the latitude scale is used for measuring distances
because one minute of latitude equals one nautical mile, and the scale expands with
latitude.
Q4: The compass rose on a nautical chart shows both an outer and inner ring. The
outer ring indicates:
A. True bearings [CORRECT]
B. Magnetic bearings
C. Compass bearings
D. Relative bearings
Correct Answer: A
Rationale: The outer ring of a compass rose indicates true directions referenced to
true north, while the inner ring shows magnetic directions referenced to magnetic
north.
Q5: If the variation is 15°W and the deviation is 3°E, what is the compass error?
A. 12°W [CORRECT]
B. 18°W
C. 12°E
D. 18°E
Correct Answer: A
Rationale: Compass error is the algebraic sum of variation and deviation; 15°W
variation combined with 3°E deviation equals 12°W total error.
Q6: A true course of 270° is plotted on the chart. If variation is 10°W and deviation is
3°E, what compass course should be steered?
A. 260°
B. 280°
C. 283°
D. 277° [CORRECT]
Correct Answer: D
Rationale: Convert true to magnetic by adding westerly variation (270° + 10° = 280°),
then convert magnetic to compass by subtracting easterly deviation (280° − 3° =
277°).
Q7: Most coastal navigation charts used in the United States are based on which
projection?
A. Lambert conformal conic
, B. Gnomonic
C. Polyconic
D. Mercator [CORRECT]
Correct Answer: D
Rationale: Mercator projection is used for most coastal and harbor charts because it
allows rhumb lines to be plotted as straight lines and preserves angles for compass
bearings.
Q8: The horizontal datum referenced on a nautical chart defines the:
A. Mathematical model of the Earth's shape used for positioning [CORRECT]
B. Vertical reference for depth soundings
C. Tidal reference for mean sea level
D. Magnetic variation for the local area
Correct Answer: A
Rationale: The horizontal datum defines the mathematical model of Earth's shape
and the reference point for all latitude and longitude positions on the chart.
Q9: To transfer a course line from one part of a chart to another using parallel rulers,
you would:
A. Draw the line and measure with dividers
B. Walk the rulers across the chart using the compass rose [CORRECT]
C. Use a protractor at the nearest meridian
D. Trace the line with a pencil and straightedge
Correct Answer: B
Rationale: Parallel rulers are walked across the chart by alternately holding one rule
and rolling the other, using the compass rose to maintain the same direction.
Q10: A position given as 41° 23.5′ N, 071° 45.2′ W is expressed in:
A. Degrees, minutes, and seconds
B. Decimal degrees only
C. Degrees and minutes with decimal fractions [CORRECT]
D. UTM coordinates
Correct Answer: C
Rationale: This notation uses degrees and minutes with a decimal fraction of a
minute, which is standard for GPS and nautical chart work.
Q11: NOAA nautical chart numbers generally indicate:
A. The chart's scale and geographic region [CORRECT]
B. The year of publication
Actual 2025/2026 with Detailed Rationales | 100%
Verified | Pass Guaranteed – A+ Graded
Section 1: Coastal Navigation Fundamentals (Q1–Q12)
Q1: What is the distance represented by one minute of latitude?
A. 1 statute mile
B. 1 kilometer
C. 1 nautical mile [CORRECT]
D. 1,000 yards
Correct Answer: C
Rationale: One minute of latitude equals one nautical mile (approximately 6,076
feet), which is the standard unit of distance used in navigation.
Q2: On a nautical chart with a scale of 1:80,000, which feature would be most
accurately represented?
A. Oceanic current patterns
B. Detailed depth soundings in a small harbor
C. Coastal topography and medium-sized harbors [CORRECT]
D. Global weather systems
Correct Answer: C
Rationale: A 1:80,000 scale is a medium-scale chart suitable for coastal navigation,
showing coastal topography and medium harbors with adequate detail for inshore
passage.
Q3: When measuring distance on a Mercator projection chart, you should use the:
A. Longitude scale at the equator
B. Latitude scale at the approximate latitude of the measurement [CORRECT]
C. Chart's bar scale regardless of latitude
D. Longitude scale at the mid-meridian of the chart
Correct Answer: B
,Rationale: On a Mercator chart, the latitude scale is used for measuring distances
because one minute of latitude equals one nautical mile, and the scale expands with
latitude.
Q4: The compass rose on a nautical chart shows both an outer and inner ring. The
outer ring indicates:
A. True bearings [CORRECT]
B. Magnetic bearings
C. Compass bearings
D. Relative bearings
Correct Answer: A
Rationale: The outer ring of a compass rose indicates true directions referenced to
true north, while the inner ring shows magnetic directions referenced to magnetic
north.
Q5: If the variation is 15°W and the deviation is 3°E, what is the compass error?
A. 12°W [CORRECT]
B. 18°W
C. 12°E
D. 18°E
Correct Answer: A
Rationale: Compass error is the algebraic sum of variation and deviation; 15°W
variation combined with 3°E deviation equals 12°W total error.
Q6: A true course of 270° is plotted on the chart. If variation is 10°W and deviation is
3°E, what compass course should be steered?
A. 260°
B. 280°
C. 283°
D. 277° [CORRECT]
Correct Answer: D
Rationale: Convert true to magnetic by adding westerly variation (270° + 10° = 280°),
then convert magnetic to compass by subtracting easterly deviation (280° − 3° =
277°).
Q7: Most coastal navigation charts used in the United States are based on which
projection?
A. Lambert conformal conic
, B. Gnomonic
C. Polyconic
D. Mercator [CORRECT]
Correct Answer: D
Rationale: Mercator projection is used for most coastal and harbor charts because it
allows rhumb lines to be plotted as straight lines and preserves angles for compass
bearings.
Q8: The horizontal datum referenced on a nautical chart defines the:
A. Mathematical model of the Earth's shape used for positioning [CORRECT]
B. Vertical reference for depth soundings
C. Tidal reference for mean sea level
D. Magnetic variation for the local area
Correct Answer: A
Rationale: The horizontal datum defines the mathematical model of Earth's shape
and the reference point for all latitude and longitude positions on the chart.
Q9: To transfer a course line from one part of a chart to another using parallel rulers,
you would:
A. Draw the line and measure with dividers
B. Walk the rulers across the chart using the compass rose [CORRECT]
C. Use a protractor at the nearest meridian
D. Trace the line with a pencil and straightedge
Correct Answer: B
Rationale: Parallel rulers are walked across the chart by alternately holding one rule
and rolling the other, using the compass rose to maintain the same direction.
Q10: A position given as 41° 23.5′ N, 071° 45.2′ W is expressed in:
A. Degrees, minutes, and seconds
B. Decimal degrees only
C. Degrees and minutes with decimal fractions [CORRECT]
D. UTM coordinates
Correct Answer: C
Rationale: This notation uses degrees and minutes with a decimal fraction of a
minute, which is standard for GPS and nautical chart work.
Q11: NOAA nautical chart numbers generally indicate:
A. The chart's scale and geographic region [CORRECT]
B. The year of publication
