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The Threat of Midget Subs Today

The United States currently faces enemy forces far different than those we faced on December 7, 1941. But a relatively untold story of the attack on Pearl Harbor holds a warning that is still relevant. Just as the Japanese employed stealthy small submarines to penetrate the harbor and attack the U.S. battle fleet from below, today enemies of the nation could use the modern equivalents of these so-called "midget" submarines to infiltrate our shores.

BySteven ReichNova

fleet of midget subs

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Occupying American forces discovered scores of Japanese midget submarines at the end of World War II, including these seen at Kure Naval Base, Japan in February 1946.
Official U.S. Air Force Photograph

In recent years, Iran and North Korea have stepped up their procurement of midget subs, Colombian drug smugglers have turned to them to elude law enforcement, and, perhaps most unsettling, advances in technology have made small subs more accessible to terrorist groups. As Burl Burlingame, a military historian and author of

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Advance Force Pearl Harbor, points out, "Thanks to technological developments and clever design, what used to be available only to the world's major fleets is now attainable to the average hobbyist—or terrorist. Our coasts are more vulnerable now than during World War II."

"A single midget sub today could stealthily deliver a nuclear device capable of atomizing one of America's largest cities."

The subs may be small, but they are likely to play a significant role in the future, as they have in the past.


On the morning of December 7, 1941, Will Lehner was Fireman Second Class on the USS Ward, a patrol ship stationed at Pearl Harbor. His ship was the first American vessel to fire a shot in the war, and its target was a Japanese midget submarine.

But because the Ward encountered the submarine over an hour before the first Japanese planes arrived, Lehner was initially baffled by the mysterious craft. He recalls, "It came underneath the ship right where I was standing. I saw it and thought, 'What is that?' Because it was a rusty-brown, with what looked like a lot of moss on it. I had never seen anything like that before. And I said, 'I wonder if that is one of ours?'"

It should not have come as a surprise that Japan's strategy for the attack included sending five midget submarines as an advance force. Midget subs—typically vessels launched by a mother support ship and manned by a one- or two-person crew—are ideally suited for stealth operations, and their military use dates back hundreds of years.

American colonists, in fact, were the first to try them out. "The world's first submarine used in battle was, in effect, a midget submarine," says naval engineer and marine historian Parks Stephenson. "David Bushnell's Turtle, invented in 1775, was a one-man submersible that was designed to sneak up on British ships, drill a hole in the hull, place an explosive inside, and then escape."

archival photo of early midget submarine
David Bushnell's Turtle (1775) was among the first midget submarines.
Courtesy Naval History and Heritage Command

The Confederate Army experimented with midget subs to defeat Union blockade ships, and throughout the late 1800s, marine engineers in England, Sweden, and France designed their own versions. By the 20th century, submarine development had matured into larger, ocean-travelling craft, yet there was still a need for smaller subs for specialized purposes.

The Japanese, for their part, produced midget submarines not just for Pearl Harbor but throughout World War II. "Hundreds of midget submarines were captured at the end of the war, sitting in rows on the docks ready to attack the American fleet," says Burlingame. "It was a technology that was going to be used as a final weapon of war against the United States."

Midget subs of the 21st century

While most nations, including Japan, now employ midget-sub technology primarily for science and exploration, some countries continue to develop midget submarines more for military purposes. In several cases, that could pose a serious threat, for, as Stephenson observes, "Midget submarines are owned by what we consider rogue nations of the world."

North Korea has had midget subs in its arsenal for years, though the technology came from a continent away. As Stephenson notes, "North Korea developed the Yugo submarine from plans that they procured from Yugoslavia in 1965." Burlingame adds, "They're called 'Yugos' because the design originally is Yugoslavian, designed to patrol the Adriatic."

At about 60 feet long and six feet wide, the Yugos are slightly smaller than the Pearl Harbor midget subs. North Korea also employs the much larger, 15-man Sang-O class of midget subs. Unlike the Pearl Harbor subs, which had a range of only about 100 miles, the Sang-O subs are believed to have a range of 1,500 nautical miles. Military experts believe that the North Korean navy has dozens of them.

The technology is not only taking on new forms, it's getting smaller.

But as Stephenson points out, the details are sketchy. "It's been reported that North Korea has the largest number of midget submarines in service, but little is known about them," he says. Burlingame agrees: "Information about the small submarines of these countries is pretty speculative. The submarines built by North Korea are substantial craft with several crew. They can be more properly thought of as coastal or commando submarines. They have been used by North Korea to deliver commandos south of the 38th Parallel. They carry as many as six torpedoes, but the primary mission is coastal infiltration."

Iran's submarine arsenal

These midget subs have travelled far beyond the Korean coastline, but they didn't journey underwater. As Burlingame notes, "The submarines built by North Korea have also been sold to Iran."

Stephenson wonders: "Could an Iranian midget sub penetrate an American harbor?" If so, it could present a real danger, and in addition to getting their hands on several North Korean Yugos, the Iranians have also developed a powerful midget submarine of their own.

Russian-built midget sub
In addition to its midget subs, Iran also has full-sized submarines, such as this 230-long, Russian-built, Kilo-class sub.
© Associated Press

Military experts describe the Iranian Ghadir as silent enough to elude the most advanced U.S. sonar. As recently as June 2009, Iran commissioned three more Ghadir-class submarines, bringing the total number of these midget subs to seven. Like the North Korean Sang-O subs, the Ghadir subs are 50 percent longer than the Yugo, but still small enough to sneak into a harbor. And they're large enough to drop small teams of commandos onto enemy shores, damage warships, and lay underwater minefields. Iranian military sources have reported that, in addition to torpedoes, the Ghadir is also capable of launching missiles.

As is the case with North Korea, details surrounding Iran's midget sub-technology remains speculative. Still, Iranian officials claim that the subs are equipped with the latest military and technological hardware.

Drug smugglers and terrorists

As noted earlier, the current threat posed by midget submarines doesn't end with rogue nations. Law-enforcement officials report that more than a third of the cocaine smuggled into the United States from Colombia travels underwater. With a reported range of about 3,000 miles, the 60-foot-long midget subs that smugglers use don't fully submerge but rather skim the surface.

midget sub on shore
A midget sub used for drug smuggling, seized by the Colombian Navy in June 2009
© Associated Press

"These craft are actually 'submersibles' rather than true submarines, needing to have at least a snorkel and periscope above the water," Burlingame says. "This simplifies construction and limits the depth at which each can run, which lessens the amount of water pressure on the hull, important because there's no internal pressure."

And whether they're spotted along the way or actually make it to their final destination, they elude capture the same way—these midget submarines are built to sink. "They're built for one-way trips and are sunk after they're unloaded," Burlingame says. "It means that they can be constructed using relatively unskilled labor, often by Colombian Indians. The amount of cocaine smuggled into the United States via these craft has risen exponentially in the last couple of years."

That number is not likely to drop. Even though the midget submersibles are relatively easy to construct, their design and equipment are fairly sophisticated, and like all submarines, they have the advantage of being able to travel clandestinely underwater.

We can only hope that the lessons learned at Pearl Harbor will open our eyes to current threats.

"We still know very little about what's beneath the ocean surface," says Burlingame. "Submarines are ideally suited to 'black operations' because, unlike aircraft, the environment in which they travel can't be witnessed by civilians. The upshot—nobody really knows."

American law-enforcement officials fear that vessels like those used by drug smugglers could also aid rebel groups and terrorists. Burlingame agrees. "It's appalling how easily these craft enter American territorial waters, and any tiny submarine that carries tons of cocaine can also carry tons of explosives," he says. "The Tamil resistance has already started building tiny submarines specifically for terrorism."

people next to midget sub
In this photo from February 2009, Sri Lankans tour a midget sub captured from Tamil Tiger rebels in that country's 25-year-old civil war.
© Associated Press

While Tamil terrorism is currently not directed at the United States but at the government in their native Sri Lanka, the proliferation of midget submarines among rogue organizations is on the rise. Rebel groups in the Philippines and Colombia, among others, are also developing midget-submarine technology.

Future threats

The technology is not only taking on new forms, it's getting smaller. As Burlingame explains, "Advances in remote-control technology have created 'robot' submarines that don't rely on crew and don't have to surface." Further, as midget submarines enter new markets, the potential for danger only increases. Burlingame says, "Civilian midget submarines are being designed for private recreation use, and these can be easily modified for military use or terrorism."

autonomous submersible
While many of today's advanced autonomous submersibles, like this one, are vital for scientific research, similar technology can be used for nefarious purposes.
Courtesy NOAA, Ocean Explorer website

As far as Parks Stephenson is concerned, it's all come full circle. "Midget submarines formed the dawn of submarine development and are as potent a threat today as ever," he says. "A midget sub was able to penetrate America's greatest fortress in 1941 and deliver a crippling blow to the battle line of the Pacific Fleet. A single midget sub today could stealthily deliver a nuclear device capable of atomizing one of America's largest cities."

We can only hope that the lessons learned at Pearl Harbor will open our eyes to current threats and help avert another surprise attack, especially one as unthinkable as that.

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