Navies around the globe have been spooked lately by the specter of unauthorized scuba divers lurking near military bases. China claims divers approaches one of its ships, while the United States recently scrambled to chase a ghost in the water, too.
The fear of these divers, or frogmen, is a subtle indicator of global tension. And with growing concerns of major conflicts erupting in Asia, Africa, and beyond, such reports indicate a rise in Special Operations missions near seaports or the heightened paranoia of the globe’s biggest militaries. Or both.
The South China Post has a good summary of Chinese state media’s reports about that incident. The Chinese claim “a Japanese naval ship sent frogmen to approach a Chinese warship” while docked at Djibouti. (It’s telling that this drama unfolded in eastern Africa, where China is projecting its power much to Japan and India’s dismay.)
The Japanese military did not report the incident. But Jian Jiamin, a legal counselor with China’s PLA navy who served in Africa, reported the encounter to the media. Jiamin, now a prosecutor, says the Chinese ship could take “necessary measures to stop [the divers] or even to exercise its self-defense rights.”
That’s a pretty serious response to some guys in scuba gear, but such fears are on the rise. This week the U.S. Navy itself had a frogman scare at Naval Station Norfolk in Virginia. Sailors on watch spotted what they thought could be a diver in a restricted pier. The Navy scrambled helicopters and ships to scour the area, but the lockdown eventually lifted after no one was found.
Still, the high alert is reasonable considering there are more than 60 ships docked at that station, including the new USS Ford aircraft carrier. These are some prized military assets and are not to be messed with. That’s also why there’s an underwater security gate that encircles the 14 piers at Norfolk, originally built by Halo Maritime Defense, and have been deemed interesting enough to be profiled by the American Galvanizers Association.
Aside from some facts about the Navy’s history with hot-tip galvanizing, the site shares some details about the design. “The fences are constructed with modular units connected together so they can absorb water movements and levels,” the association says. ” Flotation pontoons support the steel structure and nets catch watercraft attempting to jump the pontoons, basically creating a floating fence.”
The fence isn’t exactly built to deter frogmen, though. The gate is “capable of stopping even the largest unwanted seaworthy vessel,” and so it’s a good defense against terrorists using small boats, such as the one that attacked the USS Cole in 2000 while it was docked in Yemen. But frogmen pose threats all their own, and there’s a couple good reasons why sophisticated warships are scared of them. Divers do two things really well–collecting intelligence and sabotaging vessels.
But intelligence gathering is a secondary fear when compared to sabotage.
Spying frogmen would certainly be unwelcome in any military port. They could be scouting the defenses for future missions or even leaving equipment that could record the activity inside the port. Microphones could determine what the ships are doing, from the amount of fuel they receive to the noise of the crew and engine. Fiberoptic umbilical lines between the pier and ship could be tapped. Navy piers also use wireless connection systems, and those signals could also be intercepted. (Good luck cracking the NSA encryption, though.)
Intelligence gathering is a secondary fear when compared to sabotage. A lone diver could disable a warship from below the waterline using an explosive charge. The last time a frogman struck an American ship was in 1964, when a single Vietnamese diver sank the USS Card with an explosive attached to the hull. The threat resurfaced almost 40 years later when the military disclosed the schemes of Abd al-Rahim al-Nashiri. The mastermind of Al Qaeda’s deadly suicide boat attack on the USS Cole, Nashiri apparently also trained recruits to plant explosives under docked ships in the Persian Gulf. He was captured in 2002.
The big advantages of using frogmen for such attacks is that they don’t have to be attached to a ship to blow it up. Divers can also leave underwater mines for passing ships. Sophisticated military mines can be delivered with the help of underwater vehicles. These have an array of ways to be triggered. Some use acoustic noise of ships overhead while others are attracted by magnetism. Well trained and funded terrorists could also make improvised underwater mines, or buy older military models them on the black market.
Of course, frogmen aren’t invisible. Many modern navies could locate divers with sonar, if they are trained and looking out for them. The U.S. Navy can use specially designed underwater grenades or even trained sea lions to stop them. While marine mammals’ mine hunting jobs are being taken over by underwater drones, so far no robot can catch a diver like a sea lion.
But the final line of defense against frogmen is simple vigilance. Because despite cutting edge missile defense tech, stealthy submarines, and expensive warplanes, a handful of guys in scuba gear can still scare an entire ship.