freeing vs lifeboat

freeing

noun
  • The act of making something free; liberation. 

lifeboat

noun
  • A boat especially designed for saving the lives of shipwrecked people or people in distress at sea (either launched from the shore with a crew, or else carried on board a larger ship). 

  • An emergency vehicle carried aboard a spaceship. 

verb
  • To rescue; to carry to safety 

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