life raft vs rescue

life raft

noun
  • A usually inflatable raft carried aboard a ship or airplane, used to save lives in case the vessel has to be abandoned in an emergency on the sea. 

rescue

noun
  • A special airliner flight to bring home passengers who are stranded 

  • A rescuee. 

  • A liberation, freeing. 

  • An act or episode of rescuing, saving. 

  • The forcible ending of a siege; liberation from similar military peril 

verb
  • To recover forcibly. 

  • To achieve something positive under difficult conditions. 

  • To free or liberate from confinement or other physical restraint. 

  • To save from any violence, danger or evil. 

  • To deliver by arms, notably from a siege. 

  • To remove or withdraw from a state of exposure to evil and sin. 

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