CP2 – Cathodic Protection Technician –
Maritime Certification Exam
1. The primary purpose of cathodic protection on a ship’s
hull is to:
A. Prevent mechanical damage
B. Reduce marine growth
C. Control electrochemical corrosion
D. Increase hull thickness
Answer: C
Explanation: CP reduces corrosion by shifting hull potential to
a more cathodic (negative) value.
2. The most common sacrificial anode material for ship hulls
is:
A. Magnesium
B. Titanium
C. Aluminum alloy
D. Carbon steel
Answer: C
Explanation: Aluminum–zinc–indium alloy is standard for
seawater due to high driving voltage and long life.
3. Magnesium anodes are NOT recommended for ships
because:
,A. They are too expensive
B. They corrode too slowly
C. They are too active in seawater and waste rapidly
D. They require impressed current
Answer: C
Explanation: Magnesium dissolves extremely fast in high-
chloride seawater.
4. The reference electrode commonly used in seawater CP
surveys is:
A. Cu/CuSO₄
B. Ag/AgCl/seawater
C. Hg/HgSO₄
D. Zn/ZnSO₄
Answer: B
Explanation: Silver/silver chloride electrodes provide stable
reference values in seawater.
5. A typical protection potential for steel in seawater
(Ag/AgCl) is:
A. –550 mV
B. –650 mV
C. –800 mV
D. –950 mV
,Answer: D
Explanation: –950 mV Ag/AgCl is the common CP criterion
for seawater environments.
6. ICCP systems on ships typically use:
A. MMO (mixed metal oxide) anodes
B. Magnesium anodes
C. Aluminum plates
D. Zinc ribbon
Answer: A
Explanation: MMO/Ti anodes are standard for impressed-
current hull protection.
7. The dielectric shield on a ship’s hull ICCP system helps:
A. Prevent cathode depolarization
B. Direct current into seawater efficiently
C. Protect against AC interference
D. Improve grounding
Answer: B
Explanation: The shield focuses current outward and
prevents paint burn-through.
8. Hull-mounted reference electrodes are used to:
A. Polish the hull
B. Monitor hull potential
, C. Measure paint thickness
D. Measure pH
Answer: B
Explanation: Reference cells provide real-time feedback to
the ICCP controller.
9. Zinc anodes used underwater on offshore structures
typically operate at:
A. –600 mV Ag/AgCl
B. –750 mV Ag/AgCl
C. –1000 mV Ag/AgCl
D. –1500 mV Ag/AgCl
Answer: C
Explanation: Zinc anodes normally polarize steel to around –
1000 mV in seawater.
10. A hull ICCP controller adjusts current based on:
A. Water temperature only
B. Hull potential readings
C. Ship speed
D. Anode size
Answer: B
Explanation: The control unit increases or decreases output
to maintain target potential.
Maritime Certification Exam
1. The primary purpose of cathodic protection on a ship’s
hull is to:
A. Prevent mechanical damage
B. Reduce marine growth
C. Control electrochemical corrosion
D. Increase hull thickness
Answer: C
Explanation: CP reduces corrosion by shifting hull potential to
a more cathodic (negative) value.
2. The most common sacrificial anode material for ship hulls
is:
A. Magnesium
B. Titanium
C. Aluminum alloy
D. Carbon steel
Answer: C
Explanation: Aluminum–zinc–indium alloy is standard for
seawater due to high driving voltage and long life.
3. Magnesium anodes are NOT recommended for ships
because:
,A. They are too expensive
B. They corrode too slowly
C. They are too active in seawater and waste rapidly
D. They require impressed current
Answer: C
Explanation: Magnesium dissolves extremely fast in high-
chloride seawater.
4. The reference electrode commonly used in seawater CP
surveys is:
A. Cu/CuSO₄
B. Ag/AgCl/seawater
C. Hg/HgSO₄
D. Zn/ZnSO₄
Answer: B
Explanation: Silver/silver chloride electrodes provide stable
reference values in seawater.
5. A typical protection potential for steel in seawater
(Ag/AgCl) is:
A. –550 mV
B. –650 mV
C. –800 mV
D. –950 mV
,Answer: D
Explanation: –950 mV Ag/AgCl is the common CP criterion
for seawater environments.
6. ICCP systems on ships typically use:
A. MMO (mixed metal oxide) anodes
B. Magnesium anodes
C. Aluminum plates
D. Zinc ribbon
Answer: A
Explanation: MMO/Ti anodes are standard for impressed-
current hull protection.
7. The dielectric shield on a ship’s hull ICCP system helps:
A. Prevent cathode depolarization
B. Direct current into seawater efficiently
C. Protect against AC interference
D. Improve grounding
Answer: B
Explanation: The shield focuses current outward and
prevents paint burn-through.
8. Hull-mounted reference electrodes are used to:
A. Polish the hull
B. Monitor hull potential
, C. Measure paint thickness
D. Measure pH
Answer: B
Explanation: Reference cells provide real-time feedback to
the ICCP controller.
9. Zinc anodes used underwater on offshore structures
typically operate at:
A. –600 mV Ag/AgCl
B. –750 mV Ag/AgCl
C. –1000 mV Ag/AgCl
D. –1500 mV Ag/AgCl
Answer: C
Explanation: Zinc anodes normally polarize steel to around –
1000 mV in seawater.
10. A hull ICCP controller adjusts current based on:
A. Water temperature only
B. Hull potential readings
C. Ship speed
D. Anode size
Answer: B
Explanation: The control unit increases or decreases output
to maintain target potential.
