air pressure
because if air is lighter than water and you are trying to get a tank full of water to sink you would need a whole lot of air so by compressing lots of air into the tank it makes the tank heavy so it sinks
Submarines todaee are used for underwater exploration,funn,new life underwater.
Submarines?
Seeing how submarines are designed to move underwater, the antonym that makes the most sense would be airplane.
Yes, they does.
No.
Submarines have sonars.
Submarines sink or float by adjusting their buoyancy through the use of ballast tanks. When water is pumped into these tanks, the submarine becomes heavier than the water around it, causing it to sink. Conversely, to float, the submarine expels water from the ballast tanks, reducing its weight and allowing it to rise to the surface. This ability to control buoyancy enables submarines to navigate underwater and at the surface efficiently.
They are called submarines
Ironclads are not the same thing as submarines. Ironclads do not go underwater completely even though the majority of their body may be underwater.
Submarines can stay underwater for extended periods, often ranging from several days to weeks, depending on their type and technology. Nuclear-powered submarines can remain submerged for months at a time, limited primarily by food supplies and crew endurance. Conventional diesel-electric submarines typically have shorter underwater endurance, often around a week, due to the need to surface for air or recharge batteries. Advances in technology continue to enhance the underwater capabilities of submarines.
Straight to the bottom of the ocean.
Sonar