🔍 Key Concepts

• Boiler tube failure mechanisms in marine boilers • Differences between mechanical, thermal (overheating), and chemical (corrosion) damage • How multiple distinct causes are sometimes grouped in exam answers

💭 Think About

• Think about whether boiler tubes can be damaged only by physical forces, or also by temperature problems and chemical attack. • Ask yourself: in real shipboard practice, what are the common reasons tubes are renewed or plugged? • Consider how exams often treat a list of several correct individual causes—how is that sometimes represented in the answer choices?

✅ Before You Answer

• For each option (mechanical stress, overheating, corrosion), ask: Can this realistically damage or crack a boiler tube? • Recall maintenance reports or sea stories: What do engineers actually report as causes of tube leaks or ruptures? • Check whether more than one option seems independently valid, and what that usually implies in multiple-choice questions.