cast anchor vs cast off

cast anchor

verb
  • To drop anchor or otherwise moor a ship. 

  • To take up a position. 

cast off

verb
  • To let go (a cable or rope securing a vessel to a buoy, wharf, etc.) so that the vessel may make way. 

  • To discard or reject something. 

  • To finish the last row of knitted stitches and remove them securely from the needle. 

  • To estimate the amount of space required by the type used for the given copy. 

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