forecastle vs slipway

forecastle

noun
  • A raised part of the upper deck at the front of a ship. 

  • Crew's quarters located at the forward part of a ship. 

slipway

noun
  • A sloping surface, leading down to the shore or to a river, on which ships are built, repaired or stored and from which they are launched. 

  • A slip road. 

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