In which sphere was John Phillip Holland a pioneer?
Underwater vehicles Diesel submarine Submariners SUBMARINES Diesel-electric submarine Submarines in world war 2 Patrol submarine Pig boat Submarine Submarines in World War II Military submarine Diesel submarines Fast-attack submarine Underwater boat Submarines Fast attack Submarine
pig boat military submarine submarine underwater boat submariners submarines in world war 2 fast attack submarine diesel electric submarine submarines in world war ii submarines diesel submarine underwater vehicles patrol submarine diesel submarines
submarines
WikipediaEntity
SUBMARINES