,
By Stijn Mitzer
Armed with several torpedoes and nimble in their movements, these hunters and killers of the deep dare not be dismissed by their smaller size. The potency of small submarines was reaffirmed when a North Korean midget submarine sunk the ROKS Cheonan, a Pohang-class corvette of the South Korean Navy, in 2010. The Cheonan's active sonar had failed to detect the North Korean submarine that had been lurking in the area for the past day, which fired a single 533mm torpedo at the unsuspecting target. The submarine that had caused this tragedy slipped back into the dark waters of the North unnoticed, providing a tragic reminder of the effectiveness of small submarines.