Exam Question
(a) Explain the ideal design requirements of a ship's propeller (8)
(b) Briefly describe the propeller maintenance that should be carried out to prevent the fuel being wasted. (8)
Class 2 (2nd Engineer)
MEKG
📅 Jan 2025
Reference Answer
### (a) Ideal Design Requirements of a Ship's Propeller (8 Marks)
A ship's propeller must be designed as a compromise between hydrodynamic efficiency, structural integrity, and operational constraints like vibration and noise. The ideal design aims to convert the maximum amount of engine power into effective thrust with minimal losses. The key design requirements are:
1. **Propeller Diameter:**
* **Principle:** A larger diameter is generally more efficient. It acts on a larger mass of water at a lower acceleration for a given thrust, which improves propulsive efficiency. This allows the propeller to be run at a lower RPM.
A ship's propeller must be designed as a compromise between hydrodynamic efficiency, structural integrity, and operational constraints like vibration and noise. The ideal design aims to convert the maximum amount of engine power into effective thrust with minimal losses. The key design requirements are:
1. **Propeller Diameter:**
* **Principle:** A larger diameter is generally more efficient. It acts on a larger mass of water at a lower acceleration for a given thrust, which improves propulsive efficiency. This allows the propeller to be run at a lower RPM.
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