Exam Question
With reference to hull protection against corrosion and fouling, write a brief explanation of each of the following:
(a) Sacrificial anodes (6)
(b) Impressed Current System (6)
(c) Means of preventing marine growth and fouling (4)
Class 4 (4th Engineer)
SC&S
📅 Oct 2025
Reference Answer
### (a) Sacrificial Anodes (6 Marks)
Sacrificial anode cathodic protection is a passive method of corrosion control based on the principles of the galvanic series.
**1. Principle of Operation:**
- When two dissimilar metals are electrically connected and immersed in an electrolyte (seawater), a galvanic cell is formed. The more reactive (less noble) metal becomes the anode and corrodes, while the less reactive (more noble) metal becomes the cathode and is protected.
Sacrificial anode cathodic protection is a passive method of corrosion control based on the principles of the galvanic series.
**1. Principle of Operation:**
- When two dissimilar metals are electrically connected and immersed in an electrolyte (seawater), a galvanic cell is formed. The more reactive (less noble) metal becomes the anode and corrodes, while the less reactive (more noble) metal becomes the cathode and is protected.
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