ABYC CORROSION 2026 | MARINE TECHNICIAN
STUDY & CERTIFICATION GUIDE QUESTIONS
AND 100% VERIFIED ANSWERS WITH
RATIONALES GRADED A+
GUARANTEED PASS ON THE FIRST ATTEMPT
1.
A boat owner reports rapid deterioration of a bronze propeller after installing a new
stainless-steel shaft. What is the most likely cause?
A. Crevice corrosion
B. Galvanic corrosion
C. Pitting corrosion
D. Erosion corrosion
Answer: B. Galvanic corrosion
Rationale: When dissimilar metals such as stainless steel and bronze are
electrically connected in seawater, the less noble metal (bronze) becomes anodic
and corrodes faster.
,2.
Which metal is most anodic in seawater?
A. Stainless steel
B. Aluminum
C. Zinc
D. Bronze
Answer: C. Zinc
Rationale: Zinc is intentionally used as a sacrificial anode because it is more
anodic than most marine metals and corrodes preferentially.
3.
What is the primary function of a sacrificial anode?
A. Prevent oxidation by sealing metal surfaces
B. Reduce electrical resistance
C. Corrode in place of protected metals
D. Neutralize acidic water
Answer: C. Corrode in place of protected metals
Rationale: Sacrificial anodes protect more noble metals by acting as the anode in
the electrochemical cell.
4.
A technician finds isolated deep pits on an aluminum hull. What type of corrosion
is this?
A. Uniform corrosion
B. Galvanic corrosion
C. Pitting corrosion
D. Stray current corrosion
,Answer: C. Pitting corrosion
Rationale: Pitting corrosion creates localized cavities and is common in aluminum
exposed to chlorides.
5.
Which condition is required for galvanic corrosion to occur?
A. High temperature only
B. Presence of oxygen only
C. Electrical connection and electrolyte
D. Acidic environment only
Answer: C. Electrical connection and electrolyte
Rationale: Galvanic corrosion requires dissimilar metals, an էլectrical path, and an
electrolyte such as seawater.
6.
What is the most aggressive form of corrosion in a marina environment?
A. Uniform corrosion
B. Galvanic corrosion
C. Stray current corrosion
D. Crevice corrosion
Answer: C. Stray current corrosion
Rationale: Stray current corrosion can destroy metal components rapidly due to
external electrical leakage.
7.
A boat shows corrosion only near tight joints and under gaskets. What is the likely
cause?
A. Erosion corrosion
B. Crevice corrosion
, C. Uniform corrosion
D. Electrolysis
Answer: B. Crevice corrosion
Rationale: Crevice corrosion occurs in confined spaces where oxygen levels are
low.
8.
Which metal is commonly used for sacrificial anodes in saltwater?
A. Magnesium
B. Zinc
C. Steel
D. Copper
Answer: B. Zinc
Rationale: Zinc is ideal for saltwater due to its electrochemical potential.
9.
What happens if a sacrificial anode is painted?
A. It becomes more effective
B. It stops functioning
C. It corrodes faster
D. It increases conductivity
Answer: B. It stops functioning
Rationale: Paint insulates the anode, preventing it from interacting with the
electrolyte.
STUDY & CERTIFICATION GUIDE QUESTIONS
AND 100% VERIFIED ANSWERS WITH
RATIONALES GRADED A+
GUARANTEED PASS ON THE FIRST ATTEMPT
1.
A boat owner reports rapid deterioration of a bronze propeller after installing a new
stainless-steel shaft. What is the most likely cause?
A. Crevice corrosion
B. Galvanic corrosion
C. Pitting corrosion
D. Erosion corrosion
Answer: B. Galvanic corrosion
Rationale: When dissimilar metals such as stainless steel and bronze are
electrically connected in seawater, the less noble metal (bronze) becomes anodic
and corrodes faster.
,2.
Which metal is most anodic in seawater?
A. Stainless steel
B. Aluminum
C. Zinc
D. Bronze
Answer: C. Zinc
Rationale: Zinc is intentionally used as a sacrificial anode because it is more
anodic than most marine metals and corrodes preferentially.
3.
What is the primary function of a sacrificial anode?
A. Prevent oxidation by sealing metal surfaces
B. Reduce electrical resistance
C. Corrode in place of protected metals
D. Neutralize acidic water
Answer: C. Corrode in place of protected metals
Rationale: Sacrificial anodes protect more noble metals by acting as the anode in
the electrochemical cell.
4.
A technician finds isolated deep pits on an aluminum hull. What type of corrosion
is this?
A. Uniform corrosion
B. Galvanic corrosion
C. Pitting corrosion
D. Stray current corrosion
,Answer: C. Pitting corrosion
Rationale: Pitting corrosion creates localized cavities and is common in aluminum
exposed to chlorides.
5.
Which condition is required for galvanic corrosion to occur?
A. High temperature only
B. Presence of oxygen only
C. Electrical connection and electrolyte
D. Acidic environment only
Answer: C. Electrical connection and electrolyte
Rationale: Galvanic corrosion requires dissimilar metals, an էլectrical path, and an
electrolyte such as seawater.
6.
What is the most aggressive form of corrosion in a marina environment?
A. Uniform corrosion
B. Galvanic corrosion
C. Stray current corrosion
D. Crevice corrosion
Answer: C. Stray current corrosion
Rationale: Stray current corrosion can destroy metal components rapidly due to
external electrical leakage.
7.
A boat shows corrosion only near tight joints and under gaskets. What is the likely
cause?
A. Erosion corrosion
B. Crevice corrosion
, C. Uniform corrosion
D. Electrolysis
Answer: B. Crevice corrosion
Rationale: Crevice corrosion occurs in confined spaces where oxygen levels are
low.
8.
Which metal is commonly used for sacrificial anodes in saltwater?
A. Magnesium
B. Zinc
C. Steel
D. Copper
Answer: B. Zinc
Rationale: Zinc is ideal for saltwater due to its electrochemical potential.
9.
What happens if a sacrificial anode is painted?
A. It becomes more effective
B. It stops functioning
C. It corrodes faster
D. It increases conductivity
Answer: B. It stops functioning
Rationale: Paint insulates the anode, preventing it from interacting with the
electrolyte.
