mooring vs mud hook

mooring

noun
  • The act of securing a vessel with a cable or anchor etc. 

  • Something to which one adheres, or the means that helps one to maintain a stable position and keep one's identity - moral, intellectual, political, etc. 

  • A place to moor a vessel. 

mud hook

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