🔍 Key Concepts

• Properties of lube oil and how it interacts with different metals • Engine sump construction requirements in terms of strength, cleanliness, and heat resistance • Typical materials used in large engine crankcases and sumps on commercial vessels

💭 Think About

• Which material will best withstand hot lubricating oil over long periods without contamination or weakening? • Which choice focuses on structural integrity and cleanliness rather than just corrosion prevention? • Are any of the listed materials unusual or rarely used in marine main engine sumps?

✅ Before You Answer

• Verify which option is a commonly used construction material for large main engine sumps in practice • Consider which materials could react with or contaminate lube oil over time • Check which option emphasizes cleanliness and strength instead of special alloys or coatings