dragnet vs grappling iron

dragnet

noun
  • A net dragged across the bottom of a body of water. 

  • Heightened efforts by law-enforcement personnel to capture suspects. 

verb
  • To make heightened efforts to catch a suspect. 

  • To drag a net across the bottom of a body of water. 

grappling iron

noun
  • A metal hook, attached to the end of a line, used to hold two ships together. 

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