ASA 105 Coastal Navigation ACTUAL
EXAM [2025/2026] | 75 Questions |
Detailed Rationales | Pass Guaranteed - A+
Graded
SECTION 1: Nautical Charts & Chart Symbols (12 Questions)
Q1: On a chart using IALA Region B (Americas), a nun buoy painted with red and green
horizontal bands and exhibiting a quick-flashing (Qk Fl) green light marks which feature?
A. Isolated danger
B. Preferred channel to port
C. Preferred channel to starboard
D. Fairway buoy
Correct Answer: C
Rationale: In IALA Region B, red/green horizontal bands with a green light (top band
green) indicate a preferred channel to starboard; the quick-flashing green light confirms
the navigator should keep the buoy on the port side when returning from sea.
,Q2: What does a magenta dashed line with the label "DW" represent on a NOAA nautical
chart?
A. Deep water route
B. Degaussing range
C. Dumping ground
D. Submarine cable
Correct Answer: A
Rationale: A magenta dashed line labeled "DW" indicates a deep water route established
for vessels that require greater depths than those available in surrounding waters.
Q3: On a Mercator projection chart, which of the following statements is TRUE?
A. A nautical mile is equal to one minute of longitude at all latitudes
B. Great circles plot as straight lines
C. Rhumb lines plot as straight lines
D. The scale is constant across the entire chart
Correct Answer: C
Rationale: On a Mercator projection, rhumb lines (lines of constant bearing) plot as
straight lines. Great circles appear curved, and the scale expands with latitude, making
one minute of latitude equal one nautical mile everywhere, while one minute of
longitude varies.
,Q4: A charted depth of "18" with a blue tint surrounding it indicates:
A. A depth of 18 feet in a shallow water area
B. A depth of 18 meters in deep water
C. A drying height of 18 feet above chart datum
D. A submerged rock with 18 feet of clearance at mean high water
Correct Answer: A
Rationale: The number "18" without underline indicates 18 feet (or meters per chart
units) of water at chart datum. The blue tint indicates water less than the safety contour
depth, highlighting shallow areas.
Q5: You are examining a chart and see the symbol "Co" next to a rock. What does this
indicate?
A. Coral
B. Covers and uncovers
C. Coarse sand bottom
D. Conspicuous object
Correct Answer: B
Rationale: The abbreviation "Co" on a nautical chart stands for "covers and uncovers,"
indicating that the rock is submerged at high water but exposed at low water.
Q6: What is the primary purpose of the compass rose printed on a nautical chart?
, A. To indicate magnetic north only
B. To measure distances between waypoints
C. To convert between true and magnetic directions and to lay off courses
D. To identify the chart's projection type
Correct Answer: C
Rationale: The compass rose provides both true and magnetic reference circles,
allowing navigators to convert between true and magnetic bearings and to plot courses
using parallel rulers or plotters.
Q7: A chart note states "Heights in feet referred to Mean High Water." A lighthouse is
charted with a height of "65." What does this value represent?
A. The height of the light above chart datum
B. The height of the structure above mean high water
C. The focal plane of the light above mean sea level
D. The range of the light in nautical miles
Correct Answer: B
Rationale: When heights are referred to Mean High Water, the charted value indicates
the height of the structure above the mean high water datum, distinguishing it from the
focal plane height which is measured above mean high water or mean sea level
depending on the chart.
EXAM [2025/2026] | 75 Questions |
Detailed Rationales | Pass Guaranteed - A+
Graded
SECTION 1: Nautical Charts & Chart Symbols (12 Questions)
Q1: On a chart using IALA Region B (Americas), a nun buoy painted with red and green
horizontal bands and exhibiting a quick-flashing (Qk Fl) green light marks which feature?
A. Isolated danger
B. Preferred channel to port
C. Preferred channel to starboard
D. Fairway buoy
Correct Answer: C
Rationale: In IALA Region B, red/green horizontal bands with a green light (top band
green) indicate a preferred channel to starboard; the quick-flashing green light confirms
the navigator should keep the buoy on the port side when returning from sea.
,Q2: What does a magenta dashed line with the label "DW" represent on a NOAA nautical
chart?
A. Deep water route
B. Degaussing range
C. Dumping ground
D. Submarine cable
Correct Answer: A
Rationale: A magenta dashed line labeled "DW" indicates a deep water route established
for vessels that require greater depths than those available in surrounding waters.
Q3: On a Mercator projection chart, which of the following statements is TRUE?
A. A nautical mile is equal to one minute of longitude at all latitudes
B. Great circles plot as straight lines
C. Rhumb lines plot as straight lines
D. The scale is constant across the entire chart
Correct Answer: C
Rationale: On a Mercator projection, rhumb lines (lines of constant bearing) plot as
straight lines. Great circles appear curved, and the scale expands with latitude, making
one minute of latitude equal one nautical mile everywhere, while one minute of
longitude varies.
,Q4: A charted depth of "18" with a blue tint surrounding it indicates:
A. A depth of 18 feet in a shallow water area
B. A depth of 18 meters in deep water
C. A drying height of 18 feet above chart datum
D. A submerged rock with 18 feet of clearance at mean high water
Correct Answer: A
Rationale: The number "18" without underline indicates 18 feet (or meters per chart
units) of water at chart datum. The blue tint indicates water less than the safety contour
depth, highlighting shallow areas.
Q5: You are examining a chart and see the symbol "Co" next to a rock. What does this
indicate?
A. Coral
B. Covers and uncovers
C. Coarse sand bottom
D. Conspicuous object
Correct Answer: B
Rationale: The abbreviation "Co" on a nautical chart stands for "covers and uncovers,"
indicating that the rock is submerged at high water but exposed at low water.
Q6: What is the primary purpose of the compass rose printed on a nautical chart?
, A. To indicate magnetic north only
B. To measure distances between waypoints
C. To convert between true and magnetic directions and to lay off courses
D. To identify the chart's projection type
Correct Answer: C
Rationale: The compass rose provides both true and magnetic reference circles,
allowing navigators to convert between true and magnetic bearings and to plot courses
using parallel rulers or plotters.
Q7: A chart note states "Heights in feet referred to Mean High Water." A lighthouse is
charted with a height of "65." What does this value represent?
A. The height of the light above chart datum
B. The height of the structure above mean high water
C. The focal plane of the light above mean sea level
D. The range of the light in nautical miles
Correct Answer: B
Rationale: When heights are referred to Mean High Water, the charted value indicates
the height of the structure above the mean high water datum, distinguishing it from the
focal plane height which is measured above mean high water or mean sea level
depending on the chart.
