🔍 Key Concepts

• Boiler expansion and thermal growth in marine installations • Difference between fixed (rigid) supports and sliding/expansion supports on drums and saddles • Purpose and maintenance of sliding feet and chocks on boiler foundations

💭 Think About

• When a boiler heats up, what happens to the length of the drums and how must the foundations be arranged to allow for this? • If one end of the water drum is fixed, what must be true about the other end to avoid excessive stress on the drum and ship’s structure? • How would poor maintenance (rusted/painted sliding surfaces) affect the ability of the foundation to do its job?

✅ Before You Answer

• Verify which parts of the support are intended to be rigidly attached vs. which are intended to slide to absorb expansion. • Check whether good maintenance would involve making sliding surfaces too tight, or keeping them clean, smooth, and free to move. • Consider whether all statements can be simultaneously true, or whether one of them clearly conflicts with the physical need for thermal expansion.