On Saturday, 27 December, an Iranian fast attack craft reportedly conducted a short-notice rocket launching exercise in the vicinity of USS Harry S Truman (CVN-75) as the carrier transited the Strait of Hormuz, heading inbound to the Persian Gulf.
Iran’s attack craft are small boats equipped with machine guns, rocket launchers, and in some cases anti-ship cruise missiles and/or torpedoes (see here for a summary from 2013). They are operated by the Islamic Revolutionary Guard Corps Navy (IRGCN), and patrol the Persian Gulf constantly. They also appear in most of Iran’s naval exercises.
At least one rocket hit the water some 1,500 yards from the carrier. Also in company with Truman were USS Bulkeley (DDG-84), an Arleigh Burke-class Aegis destroyer, and a French frigate (probably the Aquitaine, which left its homeport of Brest on 17 December headed for the Persian Gulf). Bulkeley would have been serving as the carrier’s main escort, defending the air space around the Truman during the critical strait-transit period.
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A military spokesman noted that the Iranians’ action on Saturday was provocative and unsafe:
“The IRGCN’s actions were highly provocative,” Cmdr. Kevin Stephens, spokesman for the U.S. Fifth Fleet, said Wednesday in a statement.
“Firing weapons so close to passing coalition ships and commercial traffic within an internationally recognized maritime traffic lane is unsafe, unprofessional, and inconsistent with international maritime law.”
Military Times’ report indicates that the Iranians gave only 23 minutes’ notice of their launch exercise, which apparently was announced by voice on the international bridge-to-bridge radio channel. For a live fire exercise, this short notice is extraordinary, and out of keeping with sound, conventional practice. That’s especially the case in a restricted area like the Strait of Hormuz, where even the shortest-range weapons pose a potential danger to innocent shipping.
The intent to provoke is clear. But beyond marveling over that, and observing that the Iranians think Obama’s a patsy, we need to reflect on the nature of the action itself: that is, launching rockets from an attack craft near the carrier, in the Strait of Hormuz.
In February, after Iran came out with a deeply silly video showing an aircraft carrier replica being towed out and attacked by Iranian navy assets, I wrote a post about how Iran could, in fact, create the conditions to successfully attack a U.S. carrier in.
One of the assets Iran would use is her fast attack boats. I summarized the approach thus:
The capability Iran has is of combining multiple threats to distract and harass the carrier, and her escort(s), in a way that could open a window for a basically suicidal, but effective, attack on the carrier’s propulsion system and/or keel.
Briefly, the combination of tactics would work best just at the Persian Gulf-side opening from the Strait of Hormuz. It would involve running high-speed boats in swarms around the carrier and escort(s) to create an environment of distraction (the carrier would probably have only one dedicated escort, so I will refer from here on to a single escort). Simultaneously, Iran could increase the level of distraction by spinning up the fire control radar for coastal anti-ship cruise missiles deployed to the coastline in the immediate vicinity.
The small craft might lay mines as well, or at least pretend to. While creating distractions for the escort(s) and the carrier, the Iranians would slip submarines in down below, and attack the carrier in the most vulnerable, highest-payoff spot: her propulsion screws at the keel.
In light of that, a few observations on Saturday’s event:
1. Launching rockets from attack boats zipping along near the carrier would increase the distraction/confusion factor significantly for the coalition formation. We haven’t been told what the attack craft launched on Saturday, but it could have been naval-launched 107mm Fajr-1 rockets, which Iran is known to have on a number of the small craft. The range would be about 5 nautical miles (a little over 6 statute miles) for this system.
In a less likely scenario, it could also have been Fajr-3 (240mm) or even Fajr-5 (333mm) rockets. Iran is thought to have equipped a couple of attack boats with these more powerful systems.
2. For their part, Bulkeley and Truman bring their CIWS (close-in weapon system) and Truman’s RAM (rolling-airframe missile) air defense system. Although short-range rockets are a threat these systems can take on, their performance against rockets isn’t as well tested as their performance against anti-ship missiles. Unguided short-range rockets aren’t what the systems are optimized for.
Aquitaine, one of France’s newest military assets, is the lead unit of a new frigate class, with many state-of-the-art features. The ship’s Aster anti-missile system is in that category – but Aster, like the Aegis/Standard Missile(SM)-series defense system on U.S. ships, is optimized for defense against more powerful, longer-range cruise and ballistic missile threats. The frigate isn’t equipped with a CIWS-type system, according to its published specifications.
3. This raises point three: that the artillery rocket threat, adapted to the maritime environment, is one that could prove vexing for advanced navies. One attack craft launching from a distance isn’t a good representation of the threat; with Iran, there could be several dozen swarming a U.S. or coalition formation of 2-3 ships.
At the moment, it’s not clear that the desired measure of effectiveness would be shooting down or otherwise dealing individually with each and every rocket. Most of them, if unguided, would plop harmlessly in the water. We could dub an appropriate doctrinal attitude the “Iron Dome” approach, named for Israel’s lower-tier rocket/missile defense system, which is operated on the let-‘em-plop principle. Iron Dome tracks everything, but is used to actually intercept only the incoming rockets that will land in an inhabited area and/or come near a high-value military target.
That said, tracking and predicting the harmless plopping with certainty is a problem advanced navies mostly aren’t equipped for. And if the rockets do get fortified with guidance, the problem would change anyway.
4. A number of media outlets have noted that Israel and India just tested the Barak-8 maritime missile defense system, which is intended to have capabilities relevant to the Fajr-rockets-at-sea problem. The Barak-8 is known informally as “Iron Dome for ships”; Israel first tested it live from a ship only a month ago. It would clearly show promise for dealing with the potential attack-craft rocket threat, in at least some scenarios.
5. But it’s a serious question whether its capabilities are the real answer for the combined-platform, multi-vector attack by which Iran might bring down a U.S. aircraft carrier. Even if a transiting U.S. task group could fend off every rocket launched at it in the Strait of Hormuz, the sheer distraction factor, combined with the other factors Iran can bring to bear, would still serve to make breaches in the ships’ overall defense awareness likely.
The most important thing we don’t know about Saturday’s rocket launches is what else was going on. Given the Iranians’ overall posture, we should not discount the possibility that Iran was probing and practicing, as much as provoking. We should wonder if coastal cruise missile systems were active, and if there were Iranian submarines thought to be underway.
Ultimately, the best way to keep the Iranians from successfully attacking one of our carriers is to deter them from even starting such an attempt. Unfortunately, the president has frittered away the conditions for such deterrence. We are left with the very real concern that the Iranians can marshal the cheap, plentiful, low-level forces needed for a chokepoint attack on one of our iconic flagships – and are showing in every possible way what their intentions with this capability are.
