Exam Question
Write short notes on the following with details of the system and the purpose with neat sketch, as necessary:
(a) Shaft hull grounding system (8)
(b) Rudder grounding system (8)
Class 4 (4th Engineer)
MET
📅 Nov 2025
Reference Answer
### (a) Shaft Hull Grounding System (8 Marks)
#### 1. Purpose and Principle of Operation
The ship's propeller shafting is electrically insulated from the hull by the lubricating oil film in the stern tube, intermediate, and main engine bearings. A potential difference (voltage) develops on the shaft due to two primary phenomena:
* **Electromagnetic Induction:** The large bronze propeller rotating in the Earth's magnetic field and the ship's own magnetic field acts as a Faraday disk, inducing a voltage along the shaft.
#### 1. Purpose and Principle of Operation
The ship's propeller shafting is electrically insulated from the hull by the lubricating oil film in the stern tube, intermediate, and main engine bearings. A potential difference (voltage) develops on the shaft due to two primary phenomena:
* **Electromagnetic Induction:** The large bronze propeller rotating in the Earth's magnetic field and the ship's own magnetic field acts as a Faraday disk, inducing a voltage along the shaft.
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