How do submarines stay underwater?

Indeed sir, the secret of a submarine's ability to remain beneath the waves lies in its ballast system. Submarines use tanks filled with water to submerge, when these tanks are flooded, the submarine becomes heavier than the water it displaces and sinks. To resurface, compressed air is released into the tanks, pushing out the water and reducing the submarine’s weight, allowing it to rise. This clever mechanism enables submarines to move gracefully between the surface and the depths with remarkable ease, a feat that would surely impress even the most seasoned sailors.