U.S. can prevent Iran from closing Straits of Hormuz
The U.S. Navy is well prepared and ready to defend against Iranian attempts to close the Straits of Hormuz.
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In addition to the substantial programme of air strikes and missile attacks on nuclear, missile and defence facilities, US military operations would also be aimed at pre-empting any immediate Iranian responses. Most significant of these would be any possible retaliatory Iranian action to affect the transport of oil and liquefied natural gas through the Straits of Hormuz. On the assumption that this would be an obvious form of retaliation, it would be necessary to destroy coastal anti-ship missile batteries and Iran’s small force of warships. The main base and dockyard is at Bushehr; the operational headquarters is at Bandar Abbas which is also the base for Iran’s small flotilla of Russian-built Kilo-class submarines, although Chah Bahar is due to become the new base for these three boats. Other bases for light naval forces include Kharg Island at the head of the Gulf and islands in the Abu Musa group south-west of the Straits of Hormuz, these being heavily defended and well supplied.
Most of these countries rely on the safe transport of oil through one 21-mile-wide waterway: the Strait of Hormuz, which leads out of the Persian Gulf into the Indian Ocean and through which 16.5-17.0 million barrels of oil were shipped daily in 2004 (accounting for nearly 25 percent of global oil shipments). Oil bound for China, Japan, and the West Coast of the United States from the Middle East must also transit the Strait of Malacca and the Strait of Singapore, both of which carried 11.7 million barrels per day in 2004. These passageways are the chokepoints where the potential for the disruption of tanker traffic by terrorist attacks or naval blockades is greatest.But in reality the risks to maritime flows of oil are far smaller than is commonly assumed. First, tankers are much less vulnerable than conventional wisdom holds. Second, limited regional conflicts would be unlikely to seriously upset traffic, and terrorist attacks against shipping would have even less of an economic effect. Third, only a naval power of the United States' strength could seriously disrupt oil shipments, but the United States is more likely to protect shipping on the high seas than to do anything to endanger it. Fourth, if any country attempted to interfere with international shipping, a coalition would inevitably form to keep traffic flowing with manageable damage to oil deliveries and the global economy. Finally, although all-out wars between major powers can seriously disrupt maritime shipping, the chances of such a conflict happening in the foreseeable future are remote.
Mines and conventional-warhead missiles are even less effective now against large modern tankers than they were in the past. During the Iran-Iraq War, several oil tankers ran over mines in the Strait of Hormuz, but they sustained little damage due to their size and the protective effect of the liquid petroleum they carried (petroleum is not explosive in the airless tanks, and its weight holds the hulls in place). Even the most modern antiship missiles have relatively small warheads that are designed to damage the sensors and weapons systems of surface warships but are not capable of sinking or disabling a large tanker. Most missiles shot at a tanker would explode on its large deck, causing minimal damage. Even if they penetrated the deck, they would explode inside tanks where the liquid oil or the water in ballast would absorb the blast without igniting. In order to disable a modern-day tanker, an attack would have to include a salvo of eight to ten missiles with conventional warheads; a sustained campaign would quickly exhaust the missile stockpile of a medium-sized military power.
The greater number of tankers traveling at higher speeds and in more congested shipping lanes makes it increasingly difficult to identify and intercept them. This is especially true for submarines, which have a limited ability to identify surface ships and have only a small onboard supply of torpedoes and antiship missiles. If a submarine attacks a ship using just two torpedoes, it will have exhausted more than a tenth of its standard arsenal. Meanwhile, other potential targets nearby will disperse, forcing the submarine to relocate. A single conventional-power submarine (Iran has only three) facing no opposition could realistically expect to damage about half a dozen oil tankers in a busy sea-lane several hundred miles wide over the course of a month, disrupting at most a tiny fraction of the oil deliveries made during that period. Conventional-power submarines, moreover, are relatively slow and cannot catch modern tankers, which travel at 15-20 knots.
Iran has the capacity to attack the Strait of Hormuz from its shore, using coastal antiship missiles (such as Chinese Silkworm missiles), patrol boats, and short-range aircraft flying from nearby bases. It could also employ small, high-speed boats packed with high explosives to ram oil tankers and hostile naval vessels. But if it ever decided to target ships transporting oil from the Persian Gulf, it would have to interfere with the shipping of many neutral nations. As during the tanker war of the 1980s, a coalition of nations that have an interest in the free flow of oil from the Persian Gulf would quickly form. The United States, with the support of other nations with capable navies and the Persian Gulf states, could neutralize Iran's attacking forces with a combination of actions at sea and attacks against command-and-control facilities, missile sites, ports, and airfields along the Iranian side of the strait. The virtually certain result would be a swift defeat of the Iranian interdiction effort.
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It would be challenging, though not impossible, for Iran to use its submarines for mine laying in the strait, due to several factors. First, the underwater geography of the strait neutralizes many of the characteristic advantages of submarines. Kilos require a minimum operating depth of 45 meters, and only in a few places is the water in the strait more than 80 meters deep, limiting the use of tactics such as diving for concealment or protection. Additionally, the high salt content of gulf waters and other factors create heat currents that disturb sonar. As a result, it is harder for submarines to use passive sonar to detect ships without revealing their own location. Submarines become hidden but irrelevant platforms, or useful platforms that are easier to find. Either way, antisubmarine warfare forces gain an advantage, and U.S. ASW patrols in the gulf would be likely to detect mine-laying activity by Iranian submarines. There is evidence Iran may have realized these problems and is planning to relocate its submarines to the Gulf of Oman.
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Above all, the scenario described here points to the critical importance of early detection of any Iranian mine laying in the Persian Gulf and especially the need to keep close tabs on Iranian submarine activity. Such surveillance depends not only on U.S. activities in the region but also on those of Iran’s gulf neighbors. If the United States wishes to continue to act as the guarantor of free passage in the strait, it needs to make these monitoring activities a clear part of a broader effort to discourage Iranian attempts at harassment or closure. It also may wish to convey to Iran that, precisely because of the potential length and complexity of the operations outlined in this article, a campaign to clear the Persian Gulf of Iranian mines could quickly become a war to clear the Iranian harbors and coast of most remnants of the country’s military.
Iran closes the Strait of Hormuz. Often cited as Tehran's knee-jerk answer -- along with projections of astronomic oil-price spikes because of the disruption of supplies from Persian Gulf producers -- this option is neither feasible nor advisable for Iran. The U.S. would quickly overwhelm any effort to close the Strait, and Iran would be risking U.S. attacks on its land-based military. Direct military conflict with Washington would turn a bad situation for Iran -- disruption of its nuclear program -- into a potential catastrophe for the regime. Prudent hedging by oil traders and consuming countries (though not their strong suit, historically) would minimize any price spike.
Given the forces arrayed against them, many analysts believe Tehran will ultimately keep the straits open -- not least to allow their own oil exports to flow -- whilst finding other ways to needle its foes. If they did wish to disrupt shipping, they could briefly close off areas of the Gulf through declaring "military exercise areas," "accidentally" release oil into the main channel or perhaps launch one-off and more deniable hit-and-run attacks. The rhetoric, however, looks almost certain to continue. "This isn't the first time we have heard these types of threats," said Alan Fraser, Middle East analyst for London-based risk consultancy AKE. "Closing of the Straits of Hormuz is the perfect issue to talk about because the stakes are potentially so high that nobody wants it to happen." Henry Smith, Middle East analyst at consultancy Control Risks, says he believes the only circumstances under which the Iranians would consider such action would be if the United States or Israel had already launched an overt military strike on nuclear facilities. "Then, I think it would happen pretty much automatically," he said. "The Iranians have been saying for a long time that is an option, and they would have little choice but to stick to that. But otherwise, I think it's very unlikely."
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Although it is impossible to be certain of Iranian intentions, it is far more likely that if Iran desires nuclear weapons, it is for the purpose of providing for its own security, not to improve its offensive capabilities (or destroy itself ). Iran may be intransigent at the negotiating table and defiant in the face of sanctions, but it still acts to secure its own preservation. Iran’s leaders did not, for example, attempt to close the Strait of Hormuz despite issuing blustery warnings that they might do so after the EU announced its planned oil embargo in January. The Iranian regime clearly concluded that it did not want to provoke what would surely have been a swift and devastating American response to such a move.
Should Iran's rulers ever make good their threats to block the Straits of Hormuz, they could almost certainly achieve their aim within a matter of hours. But they could also find themselves sparking a punishing -- if perhaps short-lived -- regional conflict from which they could emerge the primary losers.
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