submarine

A submarine is a water‑borne vessel designed to operate underwater for extended periods. Its hull is sealed and equipped with ballast tanks that can be filled with water to dive or emptied with compressed air to surface. Propulsion is typically provided by diesel‑electric engines (diesel generators charge batteries for submerged travel) or nuclear reactors, which allow long‑duration, high‑speed underwater operation without surfacing. Submarines are used by navies for stealth attack, reconnaissance, deterrence (especially nuclear‑armed ballistic‑missile submarines), and special‑operations support, as well as for scientific research and tourism. OurNAIJA