Jennifer Dyer, a Commander (Retired) U.S. Naval intelligence offers this analysis as a guest of Connecting the Dots:
How should we think about the incident in the southern Persian Gulf on Sunday in which Iranian speedboats operated by the Iranian Revolutionary Guards Corps Navy (IRGCN) acted in a threatening manner toward a task group of three U.S. Navy ships?
The ships in question were the USS Port Royal (CG-73), a Ticonderoga-class guided missile cruiser; USS Hopper (DDG-70), an Arleigh Burke-class guided missile destroyer, and USS Ingraham (FFG-61), an O.H. Perry-class frigate. Navy and press reporting on the event indicate that the U.S.N ships acted precisely in accordance with their rules of engagement, attempting to establish contact with the Iranian boats, and to deescalate the situation. Hopper, speaking for the task group, issued warnings to the speedboats, and the boats eventually broke off and departed the area. The AP summary also indicates Hopper came close to using her M240 deck-mounted machine gun, but did not. Hopper assuredly had her gun crew manning its station, which would have been easily observed from the Iranian speedboats, and probably influenced the IRGCN decision to leave the area.
Three significant things may be said about this incident. First, U.S. rules of engagement are intended to deescalate unplanned situations, if at all possible. The reason for this is not to prevent carnage at any cost, or to behave in a pusillanimous. manner, but to restore control of the initiative and tempo to U.S. forces. The principal obligation of any commander under his rules of engagement is self-defense. But long experience with operating under U.S. rules of engagement enables a good commander to preserve his option of effective self-defense, without being drawn into action on the opponent’s timeline. We always prefer exercising our own operational agenda, on our timetable, over letting the opponent dictate it to us. The assignment of this task group was to enter the Persian Gulf for operations as directed by the U.S. Fifth Fleet Commander — and by deescalating the speedboat situation, the group stayed on task. It also avoided letting Iran provoke the U.S. into escalation at a higher level of command, either military or political.
Second, the unusual things about this situation were that the speedboat crews dumped boxes in the water, and made the provocative communication (“You will blow up”) to the U.S. Navy ships. It is, in fact, routine for our ships in the Gulf to encounter Iranian speedboats, 24/365. They very often maneuver — with zest and verve — around our ships, although rarely in a dangerous way (i.e., with bad seamanship). This incident was unusual because of the special provocation, but we have no good ways of knowing beforehand when such special provocations will erupt again. This is obviously a problem from the standpoint of warning. Which approach of Iranian speedboats might be an actual attack?
Third, small speedboats are the very devil to deal with through armed force. Hopper’s M240 (a mounted 7.62mm machine gun) was the best tool available to the three ships in question, but its range is not even 2,000 yards, and its accuracy outside 1,000 yards against a fast, maneuverable target will be iffy. The machine gun would produce suppressing fire — but if the attacker doesn’t care if he survives, and if he attacks in enough of a swarm, something will get through.
Our 5-inch naval guns would be worse than useless against such a target — in the dhow- and freighter-infested waters of the Persian Gulf, they would be bound to hit something, just not the IRGCN speedboats. A ship-launched helicopter (between them the three ships probably have at least two) is another option, but is also vulnerable to shoulder-launched missiles and machine-gun fire from the speedboats themselves. This problem is difficult enough that a truly determined, suicidal speedboat attack is more likely than not to complete potential missions like launching a rocket at a U.S. warship, or detonating pre-deployed explosives with a radio remote.
The Iranian speedboats constitute, as they did in the Royal Marines incident last March, a type of problem that rules of engagement per se can’t adequately address. Moreover, it’s not possible to guarantee prior warning to our forces that the next speedboat formation is the one that’s going to actually attack. To take summarily effective precautions against a speedboat attack would require action at the political level. The relevant tools include a demarche by the U.S. to Iran (e.g., warning Iran against operating its speedboats under specified conditions), and a Notice to Mariners — the former being more pointed, and a ratcheting up of tensions between two nations; the latter potentially inviting the contumely of all the nations whose flagged ships ply the Gulf. These are considered drastic measures; we have normally only used them when we actually went to war (e.g., during Desert Storm and Iraqi Freedom). The delineation of the conditions for breach of a demarche also becomes problematic for sound operations. If, for example, we tell Iran not to put its boats within five nautical miles of a U.S. warship, Iran will assuredly post boats at five nautical miles plus one inch off the port quarter of U.S. warships. All such delineations have the effect of standardizing what we prefer, for operational reasons, to retain unadvertised discretion over.
Of course, our national authorities can also promise Iran unspecified retaliations for any incidents of this kind in the future. If you’ve followed me this far, you will quickly deduce that announcing such triggers can cede Iran the initiative — in particular the initiative to mount ambiguous. incidents that cast doubt on our justification for responding. Retaliation warnings may or may not be appropriate here, but they work best for deterring behavior that is unmistakable.
The U.S. Navy is carrying out U.S. policy merely by being present in the Persian Gulf, and patrolling it for U.S. purposes. Our presence there every day is a neon sign to Iran that we will not tolerate Iran trying to close the Gulf, or to exercise an exclusionary hegemony over it. We tend to forget that being in Iran’s face every day IS policy, just as deliberately crossing Qaddhafi’s “Line of Death” was, in the 1980’s, and deliberately transiting the former Soviet Union’s excessively-claimed territorial waters. The U.S. Navy constantly monitors, and seeks to adjust and train to, the speedboat threat; in each of my deployments after the first Gulf war, such training and intelligence were high priorities. But it is inherently dangerous. to walk the tightwire of forward naval engagement. In a sense, this latest incident occurred not because U.S. policy isn’t working, but because it is. The Fifth Fleet Commander, and CENTCOM, will review this whole incident thoroughly and look for operational changes to make, but in the end, the policy of the United States has always been that we don’t need to suppress all other maritime activity, in order to maintain our own naval — and national — posture effectively.