🔍 Key Concepts

• Type of strainer shown (self-cleaning/recirculating with rotating scraper) and its purpose in a main reduction gear lubricating oil system • Consequences of dirty lube oil on reduction gears (wear, overheating, failure) and why frequent cleaning is needed • Difference between watchstanding routines and long‑interval scheduled maintenance (monthly, 6‑month, yearly)

💭 Think About

• From the illustration, what happens inside the strainer when handle "A" is rotated, and where does the debris go? • For equipment that protects a critical, continuously running system like a main reduction gear, would you expect cleaning to be a rare maintenance task or a routine watchstanding action? • Looking at the four choices, which interval best matches something a watchstander could reasonably be expected to do by hand while the vessel is underway?

✅ Before You Answer

• Confirm that handle "A" is a manual operating handle connected to an internal scraper or cleaning element, not a disassembly tool. • Ask yourself which answer represents a regular watchstanding practice rather than a long‑term maintenance schedule. • Consider that if this handle is not rotated often enough, the pressure drop across the strainer will increase and could starve the gear of oil. Which interval would reasonably prevent that?