[DelmarRey]

There are two types of fogging.

The first is for underway, mostly for outboards or inboards with high exposure to the elements. It is the use of a product called Salt Away mixed in a spray bottle in solution. It is sprayed on the engine and machinery and allowed to dry. This helps to eliminate the build up of salt crystals on componates.

The second is for winterizing. It is WD-40 sprayed onto the engine and machinery to protect it from moisture buildup during the wet season. In the spring it can be wipped down with a cotton rag.
Also in addition to WD-40, a heat lamp on an enclosed engine compartment keeps down the moisture build up.