pilothouse vs wheelhouse

pilothouse

noun
  • A yacht or other small vessel which has a wheelhouse. 

  • A wheelhouse. 

wheelhouse

noun
  • The enclosed structure around the paddlewheel of a steamboat. 

  • A prehistoric structure from the Iron Age found in Scotland, characteristically including an outer wall within which a circle of stone piers (resembling the spokes of a wheel) form the basis for lintel arches supporting corbelled roofing with a hearth at the hub. 

  • A pitch location which is favourable to the hitter. 

  • A building or other structure containing a (large) wheel, such as the water wheel of a mill. 

  • An enclosed compartment on the deck of a vessel such as a fishing boat, originally housing its helm or steering wheel, from which it may be navigated; on a larger vessel it is the bridge. 

  • A person's area of authority or expertise. 

  • The partially enclosed structure above and around a wheel of an automobile, typically partly formed by a portion of a fender panel that has been extended outward beyond the plane of the rest of the panel. 

How often have the words pilothouse and wheelhouse occurred in a corpus of books? (source: Google Ngram Viewer )