Don't let the funny, politically incorrect name fool you: Midget subs are a real threat. In the hands of North Korean and Iranian navies, these small vessels make good platforms for ambushes—and the U.S. Navy is clearly ready to hone its anti-submarine skills.
War tensions have been high since last week's announcement by the South Korean government that a 60-foot North Korean submarine fired a torpedo that sank a South Korean corvette and killed 46 sailors at the end of March.
The South Koreans stated that a Yeono-class (alternatively spelled "Yono") midget submarine fired the torpedo in March. They also field a larger midget submarine, the Sang-O, that fits 15 sailors. At least one of these subs was also on patrol when the attack happened, according to an international team of investigators looking into the incident with South Korea. The attack occurred in 150 feet of water, enough room for the midget submarine to maneuver.
Any sub that weighs less than 150 tons is called a midget. They can't travel too far on their own, and depend on support vessels to extend their range. In shallow water, where sonar returns are cluttered, they can prove quiet and sneaky. Often this means they can lay mines or insert commandos on beaches.
According to statements by South Korea, attacks from midget subs can also include torpedoes. Iran is known to operate midget subs, and after buying a handful from North Korea, it is believed to be making its own.
A civilian ship hired to dredge the area of the attack found remains of what the government labeled a CHT-02D torpedo, made in North Korea. That torpedo would have a big enough warhead — 250 kilograms — to destroy the corvette. Government reports state that the ship's sonar did not detect the submarine or the torpedo.
That's what concerns the U.S. Navy.
Two things heighten the risk of a similar ambush by midget submarines against U.S. ships: the complex sonar picture of shallow water where these small subs can operate, and a post–Cold War decrease in anti-submarine training.
"Instead of a large number of Soviet nuclear-powered submarines on the open ocean, advanced conventional submarines operating in the littorals have emerged as the most serious threat to U.S. forwardly deployed forces, military sealift and merchant shipping," Milan Vego, professor of operations at the Joint Military Operations Department at the Naval War College, wrote in a recent piece for Armed Forces Journal.
"The emerging threats ... are minisubmarines, swimmer-delivery vehicles, remotely operated vehicles and autonomous underwater vehicles."
This week the Pentagon announced it would step up its anti-submarine training, engaging in exercises with South Korea. The decision is "a result of the findings of this recent incident," Pentagon spokesman Bryan Whitman told reporters. But crash courses in sub hunting may not help much; professionals admit it's an art as much as a science.
The United States' sub-hunting abilities have atrophied since the Soviet Union dissolved. One obstacle to revamping anti-submarine training is bringing it out of simulators and into the real world. It takes a lot of effort to conduct a real sub hunt, but these skills need to be continuously honed. "The skills for successful conduct of anti-submarine warfare (ASW) must be maintained; otherwise, they will quickly atrophy," Vego warns.
The Navy has done a better job spending money on technology that can locate submarines. During the Cold War, permanent networks of sensors on the sea floor helped keep tabs on Soviet submarines. Similar networks have not been established or upgraded for use in new hotspots. "Undersea surveillance systems developed during the Cold War have limited effectiveness today," Vego says.
It appears the South Koreans share that lethargy, but South Korean officials now say a permanent snooping system will be installed. South Korean Lt. Gen. Park Jung-e said at a media briefing that "our plan is to reinforce submarine measures by establishing a submarine detection system in areas that are vulnerable."
The United States is also fielding a deployable piece of underwater detection technology, called the Advanced Deployable System (ADS), that is built for shallow-water emergencies. The system proposes to use expendable, battery-powered passive acoustic arrays that are connected with fiberoptic cables. The system will be integrated into the Navy's much-delayed but recently commissioned Littoral Combat Ship.