snorkel vs tubing

snorkel

noun
  • A hollow tube, held in the mouth, or mounted on and opening into a diving mask, used by swimmers for breathing underwater. 

  • A snorkel parka. 

  • A retractable tube fitted in diesel-engine submarines to allow sufficient ventilation that the engines may be used at periscope depth. 

verb
  • To use a snorkel. 

tubing

noun
  • tubes, considered as a group 

  • the recreation of riding down a river on an inner tube 

  • the recreation of tobogganing down a snowy slope or toboggan run on an inner tube 

  • a length of tube, or a system of tubes 

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