Exam Question

### (a) Advantages of Thin Shell Bearings over Thick White Metal Bearings
Thin shell bearings, typically of bi-metal or tri-metal construction, have largely replaced the traditional thick white metal (Babbitt) bearings in modern marine diesel engines due to their superior performance characteristics under high loads and speeds. The key advantages are:
1. **Higher Load-Carrying Capacity & Fatigue Strength:**
* **Thin Shell:** A strong steel backing provides robust structural support. The intermediate layer (e.g., copper-lead or aluminium-tin alloy) possesses significantly higher fatigue strength compared to white metal. This allows the bearing to withstand the high peak firing pressures of modern, highly-rated engines without cracking or de-laminating.