dead calm vs second-rate

dead calm

noun
  • The condition of a perfectly flat sea with no waves and no wind. 

adj
  • Completely still with no waves and no wind. 

second-rate

noun
  • A second-rate ship of the line. 

adj
  • Of a Royal Navy ship of the line in the Napoleonic Era: having 80–98 guns across three gun decks, a complement of 700–750, and weighing approximately 2,200 tons burthen. 

  • Of mediocre quality; not first-rate. 

How often have the words dead calm and second-rate occurred in a corpus of books? (source: Google Ngram Viewer )