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
highchloride 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
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
highchloride 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
