Fueling the fleet
Without blood pumping, animals can't live. Without fuel, aircraft don't fly. Take a firsthand look at the "grapes" aboard USS Dwight D. Eisenhower (CVN 69) as they conduct fueling operations at sea.
Every living organism has a circulatory system that moves vital fluid throughout the being. The hearts of mammals and reptiles pump blood throughout their bodies via an expansive circuit of veins and arteries. For plants it's phloem or xylem to provide nutrients for the organism to survive.
If an aircraft carrier were a living creature, the purple pipes that run throughout it pumping JP-5 jet fuel would be its veins.
Aviation Boatswain's Mates (Fuels), affectionately known as "grapes" because of their distinct purple flight deck jerseys, oversee the entire process from when fuel is received via underway replenishment to when it enters an aircraft before a flight.
Grapes are assigned to the V-4 division of an aircraft carrier and spend their days testing quality of fuels received, maintaining the pipes the run through the ship, fueling jets and more.