🔍 Key Concepts

• lubrication methods in large marine diesel engines (pressure feed vs splash vs immersion) • how crankpin bearings are located inside the crankshaft and how oil can physically reach them • difference between bearings that need forced lubrication and simple low‑speed components

💭 Think About

• Visualize a cross‑section of a large marine diesel engine crankshaft: how would oil get from the main bearing area into the crankpin in the middle? • Which of these methods can reliably deliver oil under pressure to a moving bearing surface deep inside the crankshaft? • Think about engine size and speed: which methods are more suitable for small, simple engines versus large main propulsion diesels?

✅ Before You Answer

• Check which option provides a pressurized, controlled oil supply directly into the crankpin area. • Eliminate any methods that would be unreliable at different speeds or loads for a large marine diesel main engine. • Confirm that the chosen method is standard practice on modern large marine diesels, not just small utility or splash‑lubricated engines.