Situation: a slow-speed engine with a single turbocharger; on oceanic passage a small portion of one impeller vane breaks off and impacts the charge air cooler. Possible action to enable the main engine to be operated:

1. Assess the damage: stop the engine (or reduce to a safe load) and inspect the turbocharger and the charge air cooler. Determine the extent of the damage - whether the turbocharger can still run (balance, vibration) and whether the charge air cooler is damaged (leaking, blocked).
2. If the turbocharger can still run (the broken vane is small and the rotor is still balanced enough):

• Reduce the engine load to a level the damaged turbocharger can sustain (e.g. 50-60% MCR), keeping the turbocharger speed within safe limits and monitoring vibration and temperature.
• Monitor the turbocharger for excessive vibration, noise, and temperature; if it becomes unstable, reduce load further or stop.

1. If the charge air cooler is damaged (e.g. leaking water into the air side):

• Isolate/by-pass the charge air cooler if possible, or repair the leak (e.g. plug the leaking tube).
• If the cooler cannot be used, the engine must be run at a reduced load (because the charge air temperature will be higher, limiting the air density and the power).

1. If the turbocharger cannot be run (severe damage, excessive vibration):

• The engine cannot be operated normally without the turbocharger (it would not get enough air). Options:

a. Run the engine at a very low load (e.g. 20-30% MCR) using natural aspiration (if the engine can run without the turbocharger at low load), or

b. Fit a spare turbocharger rotor if available, or

c. If a spare is not available, the engine may be operated at a reduced load with the turbocharger locked/isolated, using an auxiliary blower if fitted, to reach a port.

1. The engine should be operated at a reduced load, with the turbocharger and cooler monitored, and the ship should proceed to the nearest port for repair.

The key is to reduce the load to a safe level that the damaged turbocharger and cooler can sustain, monitor the condition, and proceed to port for repair. The exact action depends on the extent of the damage and the availability of spares.