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Fastest military submarine

Fastest military submarine
Who
Russian Alfa Class
What
40 nautical mile(s) per hour or knot(s)
Where
Not Applicable
When
2000

The Russian Alfa-class nuclear-powered submarines had a reported maximum speed of over 40 knots (74 km/h or 46 mph) and were believed capable of diving to 760 m (2,500 ft). It is believed that only one now remains in service, as a trials boat.