cutwater vs subfloor

cutwater

noun
  • The wedge of a bridge pier, that resists the flow of water and ice. 

  • The forward curve of the stem of a ship. 

  • A black skimmer; a sea bird of the species Rynchops niger, that flies low over the sea, "cutting" the water surface with its lower mandible to catch small fish. 

subfloor

noun
  • The floor structure supporting and underlying the visible flooring or other finishing surface such as a carpet 

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