The duration a submarine can stay underwater, also known as its "endurance," varies depending on the type of submarine and its design. Modern nuclear-powered submarines have significantly longer endurance compared to conventional diesel-electric submarines.
Conventional Diesel-Electric Submarines: Conventional submarines use diesel engines to generate electricity to power the submarine's systems and charge batteries. While submerged, they rely on stored electrical power from the batteries. These submarines can stay submerged for several days, typically around 1 to 3 days, before needing to resurface to recharge their batteries and replenish their oxygen supply.
Nuclear-Powered Submarines: Nuclear-powered submarines have an extended endurance due to their onboard nuclear reactors, which produce a continuous supply of electricity for propulsion and other systems. These submarines can stay submerged for weeks or even months without needing to resurface. Some nuclear-powered submarines are designed for extremely long missions and can remain submerged for several months at a time, thanks to their nuclear power source.
As for maintaining oxygen levels inside the submarine, several systems are in place:
Oxygen Generation: Submarines have systems that can produce oxygen onboard. For example, they may use an Electrolysis process that splits water into hydrogen and oxygen, with the oxygen being used to replenish the submarine's atmosphere.
CO2 Scrubbers: As the crew breathes, they produce carbon dioxide (CO2), which can be harmful if it accumulates in the air. Submarines are equipped with CO2 scrubbers, which remove carbon dioxide from the air and ensure the crew has a continuous supply of breathable oxygen.
Oxygen Storage: Submarines carry a supply of compressed oxygen for emergencies or situations where the oxygen generation systems may not be fully functional.
Crew Training: Crew members are trained to manage oxygen consumption and follow procedures to minimize unnecessary oxygen usage.
The combination of these systems allows submarines to maintain a breathable atmosphere for the crew during their extended periods underwater, enabling them to carry out their missions covertly and with extended endurance.