As shown in the illustration, what is the purpose of pressurizing the main bearing lube oil sumps on a typical marine gas turbine? Illustration GT-0023

Correct Answer: Option B — Minimizes oil leakage from the rotor shaft.

Pressurizing the main bearing sumps creates a positive pressure differential across the oil seals. This prevents lube oil from leaking out of the bearing housing into the hot gas path or compressor sections, thereby reducing oil consumption and preventing potential fire hazards or contamination of the engine's internal airflow.