navy vs vessels

navy

noun
  • A dark blue colour, usually called navy blue. 

  • A country's entire sea force, including ships and personnel. 

  • A governmental department in charge of a country's sea force. 

adj
  • Having the dark blue colour of navy blue. 

  • Belonging to the navy; typical of the navy. 

vessels

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