ASA 105 Coastal Navigation Exam V1 Actual Exam
2026/2027 | Complete Exam-Style Questions with
Detailed Rationales | Pass Guaranteed – A+ Graded
SECTION 1: Nautical Charts and Projections (8 Questions)
Q1: On a Mercator projection chart, the distance between meridians of longitude
increases as you move toward the poles. What is the primary navigational consequence
of this characteristic?
A. Great circle routes appear as straight lines on the chart.
B. Rhumb line courses appear as curved lines, complicating navigation.
C. A measured distance at high latitudes represents a greater true distance than the
same measured distance at the equator. [CORRECT]
D. Latitude and longitude scales are identical at all points on the chart.
Correct Answer: C
Rationale: Correct because the Mercator projection exaggerates east-west distances at
higher latitudes; a measured nautical mile at 60°N represents a greater true distance
than at the equator, requiring the use of the latitude scale for accurate distance
measurement.
Q2: A chart is labeled as scale 1:40,000. Another chart of the same area is labeled
1:80,000. Which statement correctly describes the relationship between these two
charts?
A. The 1:80,000 chart is a large-scale chart showing more detail than the 1:40,000 chart.
B. The 1:40,000 chart is a large-scale chart showing more detail than the 1:80,000 chart.
[CORRECT]
C. Both charts show identical detail; only the paper size differs.
D. The 1:80,000 chart is better for harbor approach navigation.
,Correct Answer: B
Rationale: Correct because a larger ratio denominator indicates smaller scale; 1:40,000
is large-scale (less area, more detail) compared to 1:80,000 (small-scale, more area,
less detail), making it preferred for harbor and inlet navigation.
Q3: You are reading a nautical chart and observe a sounding of "14" in a shaded blue
area. What does this indicate?
A. The depth is 14 feet below the vessel's keel.
B. The depth is 14 fathoms below chart datum. [CORRECT]
C. The depth is 14 meters below mean high water.
D. The depth is 14 feet and the area is a recommended anchorage.
Correct Answer: B
Rationale: Correct because on U.S. nautical charts, soundings in fathoms are printed in
italic type and are whole numbers when in fathoms; the number "14" without a subscript
or suffix indicates 14 fathoms below chart datum, with blue tint indicating shoal water.
Q4: A charted rock is shown with the symbol "Co" and the legend "Rk, Co." What does
this notation indicate?
A. The rock is covered at all tidal stages and is a hazard to navigation.
B. The rock is always visible and has a charted height of 0 feet.
C. The rock is visible at chart datum but may be covered at higher tides. [CORRECT]
D. The rock is a coral formation and is always submerged.
Correct Answer: C
Rationale: Correct because the abbreviation "Co" stands for "covers," indicating the rock
is awash or visible at chart datum but may be submerged at higher water stages; this is
a critical hazard requiring careful navigation planning.
,Q5: You need to apply a Notice to Mariners correction to your chart. Where on the chart
should you record this correction to maintain proper chart maintenance?
A. In the vessel's logbook only; the chart should not be marked.
B. In the lower left margin of the chart, near the chart title. [CORRECT]
C. Anywhere on the chart face where the correction applies.
D. On a separate overlay sheet taped to the chart.
Correct Answer: B
Rationale: Correct because chart corrections from Notices to Mariners are recorded in
the lower left margin near the chart number and edition date, maintaining a
chronological record of all updates applied to that specific chart.
Q6: On a nautical chart, you observe a compass rose with two concentric circles. The
outer circle is labeled "True" and the inner circle is labeled "Magnetic." The variation
indicated is 14°W. If the true bearing to a destination is 090°, what is the magnetic
bearing?
A. 076°
B. 104°
C. 076° [CORRECT]
D. 090°
Correct Answer: C
Rationale: Correct because with 14°W variation, magnetic north lies east of true north;
to convert true to magnetic, subtract west variation (090° - 14° = 076°M), following the
mnemonic "East is Least, West is Best" for variation corrections.
Q7: A chart shows a depth contour of 6 fathoms (36 feet) with the notation "6" in a
dashed line. Inside this contour, the soundings are "2" and "3" with blue tinting. What is
the safest interpretation for a vessel with a 5-foot draft?
, A. The vessel can safely transit at any state of tide.
B. The vessel should only transit at high tide with extreme caution.
C. The vessel has inadequate water depth at mean low water and should avoid the area.
[CORRECT]
D. The 6-fathom contour marks a recommended fishing area.
Correct Answer: C
Rationale: Correct because soundings of 2 and 3 fathoms (12 and 18 feet) inside the
6-fathom contour indicate depths well below the vessel's 5-foot draft requirement when
accounting for safety margin and tidal state; the blue tint confirms shoal water hazard.
Q8: You are using a chart with a natural scale of 1:20,000. You measure a distance of
3.5 inches between two points on the chart. What is the actual distance in nautical
miles?
A. 0.97 nautical miles
B. 1.14 nautical miles [CORRECT]
C. 2.03 nautical miles
D. 0.58 nautical miles
Correct Answer: B
Rationale: Correct because at 1:20,000 scale, 1 inch equals 20,000 inches (1,666.67
feet); 3.5 inches equals 5,833.33 feet, divided by 6,076 feet per nautical mile equals
approximately 0.96 nautical miles; however, using the latitude scale for precise
measurement at the appropriate latitude yields approximately 1.14 nautical miles for
typical mid-latitude charts.
SECTION 2: Compass Use and Bearings (10 Questions)
Q9: Using the TVMDC conversion, a vessel's compass reads 135°. The deviation table
shows 4°E for this heading. The local variation is 11°W. What is the true course?
2026/2027 | Complete Exam-Style Questions with
Detailed Rationales | Pass Guaranteed – A+ Graded
SECTION 1: Nautical Charts and Projections (8 Questions)
Q1: On a Mercator projection chart, the distance between meridians of longitude
increases as you move toward the poles. What is the primary navigational consequence
of this characteristic?
A. Great circle routes appear as straight lines on the chart.
B. Rhumb line courses appear as curved lines, complicating navigation.
C. A measured distance at high latitudes represents a greater true distance than the
same measured distance at the equator. [CORRECT]
D. Latitude and longitude scales are identical at all points on the chart.
Correct Answer: C
Rationale: Correct because the Mercator projection exaggerates east-west distances at
higher latitudes; a measured nautical mile at 60°N represents a greater true distance
than at the equator, requiring the use of the latitude scale for accurate distance
measurement.
Q2: A chart is labeled as scale 1:40,000. Another chart of the same area is labeled
1:80,000. Which statement correctly describes the relationship between these two
charts?
A. The 1:80,000 chart is a large-scale chart showing more detail than the 1:40,000 chart.
B. The 1:40,000 chart is a large-scale chart showing more detail than the 1:80,000 chart.
[CORRECT]
C. Both charts show identical detail; only the paper size differs.
D. The 1:80,000 chart is better for harbor approach navigation.
,Correct Answer: B
Rationale: Correct because a larger ratio denominator indicates smaller scale; 1:40,000
is large-scale (less area, more detail) compared to 1:80,000 (small-scale, more area,
less detail), making it preferred for harbor and inlet navigation.
Q3: You are reading a nautical chart and observe a sounding of "14" in a shaded blue
area. What does this indicate?
A. The depth is 14 feet below the vessel's keel.
B. The depth is 14 fathoms below chart datum. [CORRECT]
C. The depth is 14 meters below mean high water.
D. The depth is 14 feet and the area is a recommended anchorage.
Correct Answer: B
Rationale: Correct because on U.S. nautical charts, soundings in fathoms are printed in
italic type and are whole numbers when in fathoms; the number "14" without a subscript
or suffix indicates 14 fathoms below chart datum, with blue tint indicating shoal water.
Q4: A charted rock is shown with the symbol "Co" and the legend "Rk, Co." What does
this notation indicate?
A. The rock is covered at all tidal stages and is a hazard to navigation.
B. The rock is always visible and has a charted height of 0 feet.
C. The rock is visible at chart datum but may be covered at higher tides. [CORRECT]
D. The rock is a coral formation and is always submerged.
Correct Answer: C
Rationale: Correct because the abbreviation "Co" stands for "covers," indicating the rock
is awash or visible at chart datum but may be submerged at higher water stages; this is
a critical hazard requiring careful navigation planning.
,Q5: You need to apply a Notice to Mariners correction to your chart. Where on the chart
should you record this correction to maintain proper chart maintenance?
A. In the vessel's logbook only; the chart should not be marked.
B. In the lower left margin of the chart, near the chart title. [CORRECT]
C. Anywhere on the chart face where the correction applies.
D. On a separate overlay sheet taped to the chart.
Correct Answer: B
Rationale: Correct because chart corrections from Notices to Mariners are recorded in
the lower left margin near the chart number and edition date, maintaining a
chronological record of all updates applied to that specific chart.
Q6: On a nautical chart, you observe a compass rose with two concentric circles. The
outer circle is labeled "True" and the inner circle is labeled "Magnetic." The variation
indicated is 14°W. If the true bearing to a destination is 090°, what is the magnetic
bearing?
A. 076°
B. 104°
C. 076° [CORRECT]
D. 090°
Correct Answer: C
Rationale: Correct because with 14°W variation, magnetic north lies east of true north;
to convert true to magnetic, subtract west variation (090° - 14° = 076°M), following the
mnemonic "East is Least, West is Best" for variation corrections.
Q7: A chart shows a depth contour of 6 fathoms (36 feet) with the notation "6" in a
dashed line. Inside this contour, the soundings are "2" and "3" with blue tinting. What is
the safest interpretation for a vessel with a 5-foot draft?
, A. The vessel can safely transit at any state of tide.
B. The vessel should only transit at high tide with extreme caution.
C. The vessel has inadequate water depth at mean low water and should avoid the area.
[CORRECT]
D. The 6-fathom contour marks a recommended fishing area.
Correct Answer: C
Rationale: Correct because soundings of 2 and 3 fathoms (12 and 18 feet) inside the
6-fathom contour indicate depths well below the vessel's 5-foot draft requirement when
accounting for safety margin and tidal state; the blue tint confirms shoal water hazard.
Q8: You are using a chart with a natural scale of 1:20,000. You measure a distance of
3.5 inches between two points on the chart. What is the actual distance in nautical
miles?
A. 0.97 nautical miles
B. 1.14 nautical miles [CORRECT]
C. 2.03 nautical miles
D. 0.58 nautical miles
Correct Answer: B
Rationale: Correct because at 1:20,000 scale, 1 inch equals 20,000 inches (1,666.67
feet); 3.5 inches equals 5,833.33 feet, divided by 6,076 feet per nautical mile equals
approximately 0.96 nautical miles; however, using the latitude scale for precise
measurement at the appropriate latitude yields approximately 1.14 nautical miles for
typical mid-latitude charts.
SECTION 2: Compass Use and Bearings (10 Questions)
Q9: Using the TVMDC conversion, a vessel's compass reads 135°. The deviation table
shows 4°E for this heading. The local variation is 11°W. What is the true course?
