ubåtars

Ubåtar, or submarines, are watercraft capable of independent underwater operation, designed to operate submerged for extended periods and to carry out reconnaissance, strike, or deterrence missions. In Swedish, ubåt is the term for submarine, with ubåtar as the plural and ubåtars as the possessive form meaning “of submarines.”

Submarines achieve underwater capability through a combination of hull design, ballast control, and propulsion. They use ballast tanks to dive and surface, and their hulls are built to withstand water pressure at depth. Propulsion is commonly diesel-electric for many vessels, with batteries for submerged operation; some modern submarines use air‑independent propulsion to stay submerged longer without surfacing. Nuclear-powered submarines, while rarer in many regions, offer virtually unlimited underwater endurance. Armament typically includes torpedoes and, on some classes, missiles; sensors such as sonar, radar, and periscopes enable navigation and targeting while remaining covert.

Historically, the modern submarine emerged in the late 19th and early 20th centuries and saw extensive use in the world wars. Postwar developments led to greater endurance, stealth, and sensor capability, with nuclear propulsion and advanced weapons extending strategic and tactical roles. Submarines are deployed for maritime surveillance, anti-submarine warfare, anti-surface warfare, special operations, and strategic deterrence through ballistic-missile submarines.

In Sweden, submarines have been a central element of coastal defense for much of the 20th and 21st centuries. Contemporary Swedish programs include the Gotland-class and the Blekinge-class (A26), emphasizing stealth, sensor integration, and, in some cases, air-independent propulsion. Ubåtars remains a key term in Swedish naval history and practice.