Navy submarines are specialized military vessels designed to operate underwater. They are used for various missions, including surveillance, reconnaissance, and strategic deterrence. Equipped with advanced technology, these submarines can remain submerged for extended periods, making them difficult to detect. Submarines come in different classes, such as nuclear-powered submarines and diesel-electric submarines. The former use nuclear reactors for propulsion, allowing for greater range and endurance, while the latter rely on batteries and diesel engines. Both types play crucial roles in naval operations, contributing to national security and maritime defense.