Fast-attack boat
The South Dakota is a fast attack submarine, which trades the world-ending nuclear might of a ballistic missiles submarine or "boomer," as it's known, for Tomahawk cruise missiles, mines, and torpedoes.
Boomer submarines hide in oceans around the world on the longshot chance the US may call upon them to conduct nuclear warfare. These submarines are not to be seen, and avoid combat.
But fast attack subs like the South Dakota meet naval combat head-on.
One weapon makes the South Dakota a force to be reckoned with up to 1,500 miles inland: the Tomahawk. The South Dakota can hold dozens of these land-attack missiles.
Fast attack submarines like the South Dakota serve as a door-kicker, as one did in 2011 when the US opened its campaign against Libya with a salvo of cruise missiles from the USS Michigan. These submarines also must hunt and sink enemy ships and submarines in times of combat, and the South Dakota is unmatched in that department.
In the torpedo room, sailors sleep and work around the clock in case they get orders to track and kill enemy subs.
Additionally, submarines make ideal vessels for deploying US Navy SEALs, who are trained in underwater demolition and can bring aboard their own mini subs for covert operations.
Finally, by laying down mines, the South Dakota can cripple enemy submarine and ship movement, a key element of naval war.
Unlike boomer crews, the South Dakota may be called up as the first line of defense in a fight with China or Russia. Increasingly the US expects some confrontation with one of these near-peer powers.
Virginia-class submarines like the South Dakota are nuclear-powered, so they require the crew to master nuclear propulsion while underway, even in combat.
Non-nuclear submarines, some of which China operates, have the advantage of being able to shut off their motors and run on battery power. US submarines are all nuclear, so they have to keep the reactor core on around the clock. The South Dakota mitigates this by adding extra insulation to the engine room.
"We are in a Great Power Competition with a resurgent Russia and a rising China. Our National Defense Strategy’s first line of effort is to ‘Build a more lethal’ force because as it says, ‘the surest way to prevent war is to be prepared to win one,'" Rear Adm. Leonard C. Dollaga, Commander, Undersea Warfighting Development Center said of the South Dakota.
The South Dakota isn't the first of its kind, but the first to have new technologies like large vertical sonar arrays which the US says will give it an edge on Russian and Chinese ships.
Submarine combat is a very dangerous and tricky game. Any sonar or radar ping can reveal a sub's location, so the ships need to sit and listen quietly to safely line up a kill.
The South Dakota can detect ships and subs with an offboard array of sensors that it can communicate with in near real time. This represents a breakthrough in undersea warfare and a first for the South Dakota.