If a vessel is to be laid up for an extended period of time with minimal utilities provided from ashore, boilers may be laid up dry. What statement is true as it relates to protecting boiler firesides?

Correct Answer: Option D — A cap may be installed on the uptake outlet, and a ventilating unit may be installed to blow heated air into the furnace.

For dry lay-up of boilers, preventing internal corrosion is critical. Installing a cap on the uptake and using a ventilating unit to blow heated air into the furnace maintains a low relative humidity environment. This prevents moisture accumulation on the fireside surfaces, significantly reducing the risk of accelerated corrosion.