- Can carry up to 2 Cruise Missiles or Nukes
- Can Bombard Sea Units
Powered by a nuclear reactor, the Nuclear Submarine is a considerable improvement on the standard Submarine unit. It can travel great distances and go deeper than any preceding naval unit. And, like a standard sub, it is capable of striking targets without detection.
The PT Boat is the only Modern Age naval unit that is capable of detecting submarines.
With the commission of the first nuclear powered submarine, the USS Nautilus, in 1954, the nature of naval combat and, particularly, submarine tactics, was forever altered. Before this, conventional, diesel-electric submarines approached their target on the surface to avoid draining their batteries. They submerged only when just out of sight of their target and could only approach at very low speeds. Commanders did this to conserve battery power for after their attack when they would have to use full underwater power to evade counterattack. Even after this, a full battery charge would last only an hour or two at top underwater speed. This limitation suited submarines to attacking slower, less defended ships, and meant that they could not engage fast surface warships, such as battleships and aircraft carriers.
Nuclear submarines, by contrast, had a single power supply for both surface and submerged operation. Powered by the small amount of enriched uranium fuel in its reactor, a nuclear sub could operate fully submerged at full speed indefinitely. They could operate freely before and after attacking, keeping up with the fastest of surface ships. In the Falkland Islands conflict of 1982, the British nuclear submarine, HMS Conqueror, demonstrated its revolutionary new power by tracking the swift Argentinean cruiser General Belgrano for more than 48 hours before closing in to sink it. For the first time, fast warships were vulnerable to submarine attack.
Although major world powers continued to develop both diesel-electric and nuclear vessels concurrently, some abandoned the old technology altogether. Over the course of the next four decades, nuclear submarines gradually took over in the navies of the United States, Britain, France, the Soviet Union and China.