Exam Question
(a) Explain the purpose and applications of using lubricating oils on board (8)
(b) Name the types of lubricating oil used on ships and mention various properties of same and their significance (8)
Class 4 (4th Engineer)
MEKG
📅 Mar 2023
Reference Answer
### (a) Purpose and Applications of Lubricating Oils on Board
The primary function of lubricating oil is to interpose a fluid film between moving surfaces to minimize friction and wear. However, its roles on a modern vessel are multifaceted and critical for machinery reliability and longevity.
1. **Friction Reduction (Lubrication):**
* **Principle:** The oil forms a hydrodynamic or elasto-hydrodynamic film that separates moving parts, replacing high-friction solid-to-solid contact with low-friction fluid shear. This film's ability to support the load is dependent on the oil's viscosity and the relative speed of the surfaces.
The primary function of lubricating oil is to interpose a fluid film between moving surfaces to minimize friction and wear. However, its roles on a modern vessel are multifaceted and critical for machinery reliability and longevity.
1. **Friction Reduction (Lubrication):**
* **Principle:** The oil forms a hydrodynamic or elasto-hydrodynamic film that separates moving parts, replacing high-friction solid-to-solid contact with low-friction fluid shear. This film's ability to support the load is dependent on the oil's viscosity and the relative speed of the surfaces.
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