DSV Deep Submergence Vehicle
 
  DSV Trieste 1      
  DSV-1 Trieste II 1     mod. DSV Trieste Class
  DSV-2 Alvin 1      
  DSV-2 Alvin (mod.) 1     mod. DSV-2 Alvin Class
  DSV-3 Turtle 2      

DSRV Deep Submergence Rescue Vehicle
 
  DSRV-1 Avalon 2      

NR Nuclear Research Submarine
 
  NR-1 1      

X Midget Submarine
   
  X-1 1      
  X-2 -