Which of the following operational practices is helpful in avoiding the accumulation of condensate in the main reduction gear casing?

Correct Answer: Option D — After the main unit is secured, lubricating oil should be circulated until the temperature of the oil and reduction gear casing approximates the engine room temperature.

Circulating lube oil until the reduction gear casing cools to ambient temperature prevents internal moisture condensation. Hot metallic casings exposed to humid machinery space air will sweat and contaminate the oil charge if allowed to cool uncirculated.