BDOC NSS LATEST QUESTIONS 2026
STUDY GUIDE COMPREHENSIVE
QUESTIONS ANSWERS VERIFIED A+
◉ Primary Major Light.
Answer: Established for making landfall from sea
◉ Secondary Major Light.
Answer: Established at harbor entrances
◉ Minor Lights.
Answer: Low to moderate intensity light used to mark a specific channel
or location
◉ Two considerations for minor lights.
Answer: o Care should be taken NOT to confuse minor lights with
lighted buoys
o Established in harbors, channels, rivers, and isolated locations
◉ Sector Lights.
Answer: o Red: Danger Areas
o Green: Turning Points or best water areas
o White: Good water
,◉ Buoy Shapes.
Answer: Can, Nun, Pillar, Spar, Sphere
◉ Purpose of Buoys.
Answer: Aids to navigation and used to mark
o Channels
o Shoals
o Obstructions
o Warn of Dangers
◉ IALA A.
Answer: Red port, Green Starboard when returing to harbor (Countries
in Africa, Asia, Australia, Europe)
◉ IALA B.
Answer: Green port, Red Starboard when returning to harbor (Countries
like America, Japan, Korea, and the Philippines)
◉ Variation.
Answer: The angular difference between the true meridian and the
magnetic meridian
o True Bearing = Magnetic Bearing + Variation
◉ Deviation.
, Answer: The deflection right or left of the magnetic meridian caused by
magnetic properties of the vessel
◉ Gyrocompass Error.
Answer: The difference between the true heading and gyrocompass
heading. Caused by: friction, ship's motion, electronic malfunction, and
power fluctuations
◉ Permenant Magnetism.
Answer: The stable magnetic condition of the ship, created by
construction and materials used
◉ Induced Magnetisim.
Answer: Magnetism acquired by the ships placement in the earth's
magnetic field
◉ Datum.
Answer: The mathematical model of the earth used to calculate position
coordinates, heights, and distances
◉ Datum used by US Navy.
Answer: WGS 84 (World Geodetic System 1984)
◉ Three segments of GPS.
Answer: Control, User, Space
STUDY GUIDE COMPREHENSIVE
QUESTIONS ANSWERS VERIFIED A+
◉ Primary Major Light.
Answer: Established for making landfall from sea
◉ Secondary Major Light.
Answer: Established at harbor entrances
◉ Minor Lights.
Answer: Low to moderate intensity light used to mark a specific channel
or location
◉ Two considerations for minor lights.
Answer: o Care should be taken NOT to confuse minor lights with
lighted buoys
o Established in harbors, channels, rivers, and isolated locations
◉ Sector Lights.
Answer: o Red: Danger Areas
o Green: Turning Points or best water areas
o White: Good water
,◉ Buoy Shapes.
Answer: Can, Nun, Pillar, Spar, Sphere
◉ Purpose of Buoys.
Answer: Aids to navigation and used to mark
o Channels
o Shoals
o Obstructions
o Warn of Dangers
◉ IALA A.
Answer: Red port, Green Starboard when returing to harbor (Countries
in Africa, Asia, Australia, Europe)
◉ IALA B.
Answer: Green port, Red Starboard when returning to harbor (Countries
like America, Japan, Korea, and the Philippines)
◉ Variation.
Answer: The angular difference between the true meridian and the
magnetic meridian
o True Bearing = Magnetic Bearing + Variation
◉ Deviation.
, Answer: The deflection right or left of the magnetic meridian caused by
magnetic properties of the vessel
◉ Gyrocompass Error.
Answer: The difference between the true heading and gyrocompass
heading. Caused by: friction, ship's motion, electronic malfunction, and
power fluctuations
◉ Permenant Magnetism.
Answer: The stable magnetic condition of the ship, created by
construction and materials used
◉ Induced Magnetisim.
Answer: Magnetism acquired by the ships placement in the earth's
magnetic field
◉ Datum.
Answer: The mathematical model of the earth used to calculate position
coordinates, heights, and distances
◉ Datum used by US Navy.
Answer: WGS 84 (World Geodetic System 1984)
◉ Three segments of GPS.
Answer: Control, User, Space
