life raft vs scow

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. 

scow

noun
  • A large flat-bottomed boat, having broad, square ends. 

verb
  • To transport in a scow. 

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