When the main reduction gear lube oil system is secured, which of the following components maintains the air within the casing at less than 35 percent relative humidity?

Correct Answer: Option D — The dehumidifier

Dehumidifiers are essential in marine gas turbine installations to prevent internal corrosion of the reduction gear and bearing housings during standby periods. By maintaining relative humidity below 35 percent, the system inhibits oxidation and moisture-related degradation of precision-machined components within the enclosed gear casing.