Underwater RPGs, floating garbage, Shazam, and other reasons why the U.S. Navy is so worried about Iran’s undersea mines

On the surface, the U.S. Navy’s much-ballyhooed, multinational countermine exercise underway this week in the Persian Gulf and the Strait of Hormuz might seem like a bit of overcompensation.

But, under the bluster, defense analysts believe the Iranian mine threat is incredibly real, lethal, and, to a degree, still murky.

What’s known is that Iran has built up and hidden mine-laying capabilities across its military, commercial and fishing fleets. Less clear is how many mines it has — from 5,000 to 20,000 depending on estimates. And these mines don’t look like the giant metal-spiked balls from World War II movies. Today’s mines are made of composite materials and Iran has been known to disguise them as floating tree branches and shipping boxes.

That’s why it is believed Iran could lay enough mines to shut down the Strait of Hormuz before the U.S. knew it even happened, according to Christopher Harmer, senior naval analyst at the Institute of the Study of War and former deputy director of future operations for the U.S. Navy Fifth Fleet.

Maybe.

"I think it’s extremely plausible," Harmer said, in an interview.

This week the U.S. is conducting the International Mine Countermeasures Exercise (IMCMEX), with more than 20 nations from around the globe. It is partly a show-of-force and partly a demonstration to make clear to Tehran that the U.S. can lead a multinational minesweeping exercise in right Iran’s back yard pool.

But the Navy is only showing their after-the-fact capability. In reality, by the time the U.S. had to launch a real mine-sweeping operation, it could be too late. Either the strait would be littered with mines, floating, sunken, or tethered to the bottom or shore, or a ship — likely an oil tanker — would have found out the hard way when it struck a mine.

Undersea mine warfare, it turns out, has become incredibly complex in part thanks to Russian and Chinese investment and Iranian re-engineering. In response, the U.S. has built a significant countermine force of its own, but only relatively recently.

"U.S. minesweeping has always been at the bottom of the totem pole, in terms of funding," Harmer said, because American navy’s had little need for them. There was no credible mine threat in American-fought wars. Not until the 1980s, when Iranian mines sunk oil tankers, did the U.S. begin to give the threat greater attention.

This year, the U.S. positioned eight minesweeper ships and eight helicopters stationed in Bahrain. The ships can stay on station for days, while the aircraft can sweep larger areas above the threat. But considering they face a stockpile upwards of 20,000 mines, minesweeping is the work of patient men.

"It is horrible, painfully excruciatingly detailed work," Harmer explained. "The guys who are good at it describe it as almost more art than science." Minesweepers watch what the water is doing, where the mines are drifting, and how they are camouflaged. The helicopters drop a sled out of the back, drag it from a long cable, and try to ping each mine and detonate them. One by one.

"It is like looking for a needle in a haystack," he said.

The Pentagon has begun buying up newer capabilities, though, and publicly has laid them out like a trade show exhibit booth. Last year, Central Command put in an urgent request to upgrade the countermine systems aboard minesweeper ships. The Navy started buying the SeaFox, dubbed a "kamikaze" underwater drone, that is already used by the British. It uses a camera to spot mines, then suicide-missions itself into them.  Check it out, here.

Online are pictures of a remote-controlled submarine-like toy called the M18 Mod 2 Kingfish. Lowered from inflatable skiff, it is an "unmanned underwater vehicle"(UUV) that has side-sonar to search for "object of interest." Newer models are less than 9-inches in diameter.

Then there is the SEABOTIX, a robotic underwater EOD specialist with a claw that places explosives next to suspect mines.

But they’re up against formidable foes. It’s unlikely Iran would close the strait using just free-floating mines, which Harmer said within a few weeks would dissipate to the shoreline or out of the gulf with currents.

Captor mines are a bigger worry — essentially "a shell that sits on the bottom of the ocean. It waits until it senses a ship coming by and then it launches a projectile at that ship."

The devices can be programmed, or attached to someone actually listening in, for the known acoustic signature of American ships. Think of the Shazam application on your phone, Harmer said.

"If Shazam can listen to 5 seconds of a song and tell you what it is out of 10,000 songs — every ship on earth has a distinct acoustic signature."

But that’s not the worst. "The one that we’re most afraid of is the EM52," he said. "That is a Chinese mine that is essentially a huge RPG that sits underwater, waits for a ship, and then shoots itself at that ships."

"We know that the Iranians absolutely bought that form the Chinese," Harmer said.

What’s happening this week in the Gulf, he said, is eerily reminiscent of when the U.S. and Russian navies were constantly testing each other in 1980s. Maybe not the same level of firepower and global implications, but certainly with a familiar intensity.

"It is really a chess match out there."