As covered: the engine,"s operated at reduced load; adopt two-level/electronic cylinder lubrication with a reduced low-load feed rate; maintain jacket water and scavenge air temperatures high enough to prevent acid condensation/cold corrosion; ensure adequate turbocharger boost and avoid surge by not operating at too low a load (if necessary two turbocharger units or VTA); maintain fuel viscosity/temperature for good atomization and monitor fuel/BN matching; run continuously at a defined slow-steaming speed within maker limits, avoiding vibration ranges; check exhaust temperatures/turbocharger condition,and maintain the boiler/economiser effectively -(monitor soot and acid deposition, soot-blow as needed. Before slow steaming confirm the load-limit settings and high-temperature alarms are operational,and that the marine diesel oil change-over arrangements exist in case of turbocharger problems. Periodic brief higher-load runs are often scheduled to remove deposits

• Cold corrosion (sulphuric acid condensing on the liner, corrosion wear;
• Carbon depositsand oil build-up in ring grooves and scavenge space from over-oiling/cold combustion, stuck rings, liner polishing, and risk of scavenge fires;
• Turbocharger mismatch: low boost, low efficiency, possible surging, soot and reduced air delivery, possibly turbocharger diffuser/cooler fouling;

• Exhaust system fouling and reduced waste-heat recovery: low exhaust temperature reduces boiler output and causes soot/acid deposits in the economiser, foulesthe turbine/casing,
• Increased maintenance: injector coking, exhaust valve and turbocharger deposit, and more frequent cleaning, and liner wear.

4 marks

Before: overhaul/clean turbocharger air side, exhaust valves, scavenge space, injectors as needed; re-set cylinder lubrication to the full-load feed rate; check engine general condition and clearances; gradually increase the load in steps allowing temperatures to stabilise, so carbon deposits burn off and thermal stress ist built up slowly; run up through, and confirm all temperatures, pressures normal

After: settle the engine at the appropriate service load; confirm turbocharger accelerates to normal speed, exhaust temperatures close to baseline, no abnormal noise/fumes; check oil/fuel temperatures, pressures, rectify any leaks, log, and bring back the normal watchkeeping rounds.