Iran's provocative statements are meant to push back in the political struggle against the U.S. But if words gave way to weapons, here's what would happen next

by Joe Pappalardo

On Monday, Gen. Alireza Tangsiri, the naval head of Iran’s Revolutionary Guards, said Iran had full control of the Persian Gulf. He added that the U.S. Navy, with its mission “to ensure freedom of navigation” worldwide, had no business being there.

These are bold, provocative statements made to influence the ongoing negotiations over sanctions and the fate of the 2015 nuclear agreement. But such a threat needs to be backed up with hardware, and Iran feels it has what it takes to except control over this vital waterway.

The geography favours the Iranians. They don’t need to blanket the entire Gulf to control it, just the narrowest parts such as the Strait of Hormuz, and those passages are vital to the world economy. About 30 percent of the world’s oil tankers pass through the Gulf via the Strait of Hormuz, which is only 33 km. (20 mi.) wide at its narrowest point. It’s a natural choke-point.

But don’t envision a WWII-style naval clash. The U.S. Navy would wreck the Iranian navy’s large vessels and warplanes. The Iranians know this, and have developed tactics and tech meant to even the odds. Here’s how they’ll try, and how the U.S. Navy will respond.

Swarm Warning

The U.S. Navy is great at destroying large ships. Its entire kill chain of satellites, radar, warplanes, torpedoes, and missiles is optimised for destroying large ships and stopping air attacks. On that front, the Iranian Navy Commander Rear Admiral Hossein Khanzadi said this year that a short-range defence system called the Kamand was ready to shoot down U.S. cruise missiles aimed at its destroyers.

But Iran's strategy doesn't rely on large boats. This month, for instance, the Pentagon noticed a major Iranian military exercise in the Gulf that involved more than 100 boats. Most of these boats are not warships, but small speedboats.

The geography favours the Iranians.

The Islamic Revolutionary Guard Corps operates flotillas of small speedboats that, despite their small size, pose an out sized threat to U.S. ships. These boats are armed with missiles; they rely on their numbers and speed to stay alive long enough to shoot those missiles. In 2018, the Iranian navy claimed to have outfitted them with new engines that allowed a longer range and higher speeds.

One anti-ship cruise missile that can incapacitate a destroyer is not the right weapon against a speedboat — and the ammunition will run out. The U.S. Navy is not as adept with taking out small speedboats, especially ones that are staffed with crews willing to die to get close enough to take a shot or even ram a U.S. ship. The Iranians say the crews are “martyrdom-seeking combatants.”

How To Fight Back

The swarm threat has been around a while now, and the United States has been looking for ways to thwart it. The short-term solution appears to be air power, with Navy and U.S. Air Force drills focused on gunning down small vessels from warplane cannons and helicopter rocket pods. A longer-term cure for swarming speedboats are lasers. They can target multiple vessels and never run out of ammunition. But lasers remain a future weapon and the sheer numbers of boats in the Iranian drill indicate a tough fight.

Iran would probably supplement its speedboat attacks with another emerging threat: missiles fired from shore that can skim the waves and damage a U.S. warship. Missiles like these have been shot at oil tankers from areas controlled by Iran-backed militias, and the lessons learned from these attacks could be used to perfect their use during an attempted blockade.

If the speedboats and missiles fail, the Iranians could always use a crude method to block traffic: park large ships in the narrow straits and scuttle them. Even blocking the Strait of Hormuz in this way would cause an economic catastrophe, and create a traffic jam of tankers that it could try to attack or seize.