How a cheap Swedish submarine 'ran rings' around a US aircraft carrier and its sub-hunting escorts

[Tony]

In 2005, the USS Ronald Reagan, a newly constructed $6.2 billion aircraft carrier, sank after being hit by torpedoes.

Fortunately, this did not occur in actual combat but was simulated as part of a war game pitting a carrier task force including numerous antisubmarine escorts against HSMS Gotland, a small Swedish diesel-powered submarine displacing 1,600 tons. Yet despite making multiple attacks runs on the Reagan, the Gotland was never detected.