Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

The US military's response to Houthi attacks on maritime shipping involves a strategic combination of drones and warships, specifically guided-missile destroyers This article explores the cost-benefit ratio of pricey munitions, the defense of warships, and the evolving battlespace threats

American warships in the Red Sea have been engaged in combat with an increasing amount of weaponry from Houthi forces in Yemen. In just a 10-hour period on Tuesday, they faced 17 drones and missiles. Houthi spokesman Yahya Saree, previously on Twitter, stated that the recent launches were in support of the Palestinian people, following their previous claim of targeting ships bound for Israel after an Israeli invasion of Gaza.

Over the past month, the Iran-backed Houthis have carried out over 100 attacks on 14 commercial and merchant vessels in the Red Sea, according to a senior US military official. In response, US Defense Secretary Lloyd Austin has announced the creation of a coalition consisting of at least 10 countries to address security concerns in the Red Sea.

Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

The Arleigh Burke-class guided-missile destroyer USS Carney is seen in the Mediterranean Sea in 2018.

Ryan U. Kledzik/U.S. Navy/AP

The coalition includes ships positioned near the Red Sea to quickly respond to any attacks. The primary objective of the initiative was to prevent future Houthi attacks, however, the militants have persisted in targeting ships near Yemen.

The Red Sea hosts a crucial global maritime trade route and the recent attacks have had widespread effects. The disruption caused by the Houthis extends to vessels from at least 44 different countries, impacting international trade on a larger scale.

According to the US Central Command, the 17 drones and missiles launched by the Houthis were successfully intercepted using weapons deployed by the guided-missile destroyer USS Laboon and F/A-18 fighter jets from the USS Eisenhower aircraft carrier.

The US Navy has not said exactly what weapons its ships are using against the Houthi attacks, but analysts said a US destroyer has a range of arms systems at its disposal.

Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

The Pentagon is seen from the air on March 3, 2022.

Joshua Roberts/Reuters

Iranian drone strikes a chemical tanker in the Indian Ocean, according to the Pentagon. The experts noted that U.S. ships have the ability to defend against such attacks using a variety of measures, including electronic warfare capabilities. This includes the use of surface-to-air missiles, explosive shells from destroyers' main guns and close-in weapons systems.

US destroyer captains have to navigate decisions about cost, inventory, and effectiveness as their missions expand, according to experts. "Drones are slower and can be vulnerable to cheaper missiles or even ship guns. Faster missiles require interception with more advanced interceptor missiles," explained John Bradford, a fellow at the Council on Foreign Relations specializing in International Affairs.

US Navys main asset – the guided-missile destroyer

The Arleigh Burke-class guided-missile destroyer, such as the USS Laboon, is the primary US asset deployed in the Red Sea to thwart attacks on shipping. Its arsenal includes a variety of missiles in its magazine, such as:

The Standard Missile-6 (SM-6) is a highly advanced weapon capable of intercepting ballistic missiles at high altitudes, as well as lower trajectory missiles and enemy ships within a range of up to 370 kilometers, as reported by the Missile Defense Project at the Center for Strategic and International Studies (CSIS). Each of these missiles costs more than $4 million.

Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

During a Missile Defense Agency test on June 5, 2008, in the Pacific Ocean west of Kauai, Hawaii, the guided-missile cruiser USS Lake Erie launched two modified Standard Missile 2 (SM-2) Block IV interceptors to intercept a short-range ballistic missile target. This event was captured in a photograph by the U.S. Navy/Getty Images/File.

The SM-2, while not as advanced as the SM-6, has a range of 185 to 370 kilometers depending on the version, and costs approximately $2.5 million each, according to CSIS. The ESSM, designed to target anti-ship cruise missiles and lower speed threats like drones or helicopters, has a range of up to 50 kilometers and costs over $1 million each, as reported by CSIS.

Experts said last week they think the US is using the SM-2 and/or ESSM missiles against the Houthi threats so far.

Pricey munitions and the cost-benefit ratio

Facing drones that can be mass-produced and deployed at a cost under $100,000, experts warn that a prolonged campaign could strain US resources. According to Alessio Patalano, a professor of war and strategy at Kings College in London, the advanced air intercept capabilities average around $2 million, making drone interception financially unsustainable.

Houthi forces are funded and trained by Iran, so they have resources for an extended fight, the experts point out.

Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

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U.S. scrambles to respond to Red Sea attacks


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Its also a question of to what lengths the US wants to go to protect merchant shipping, the analysts said.

According to former US Navy captain Carl Schuster, the Phalanx close-in weapons system on a US destroyer, equipped with Gatling guns capable of firing 4,500 rounds per minute, is capable of addressing drone or missile threats within a mile of the ship. Schuster noted that while this defense is cost-effective, it serves as the final line of defense, emphasizing the potential consequences of a miss on the lives of US personnel.

Bradford, from the Council on Foreign Relations, emphasized that a US warship may not be sunk by a single missile or drone, but it can still cause casualties and significant damage, necessitating the ship to return to port for repairs.

Defense of warships vs. protection of merchants

The Phalanx system is unable to protect merchant ships being watched over by the US destroyer, even if it is sailing miles away from the warship.

According to Sidharth Kaushal, a research fellow for sea power at the Royal United Services Institute in London, vessels primarily rely on anti-air missiles to provide wide area air defense rather than self-protection.

Kaushal explained that US warships utilize a vertical launch system (VLS) to fire anti-aircraft interceptor missiles from the deck. Each VLS cell can hold a combination of armaments, with specific numbers classified. However, there is a limited number of these armaments aboard each vessel.

Salvatore Mercogliano, a naval expert and professor at Campbell University in North Carolina, warned that if the Houthis continue to deplete a warship's inventories with successive attacks, it could lead to a shortage of munitions to protect the merchant vessels it is guarding. "While the navies can currently handle the threats posed by the Houthis, there is concern that if the attacks increase in scope and scale, the escorts may not be able to maintain a sufficient level of defense to protect commercial shipping," he added.

Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

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Video shows moment Houthi rebels storm cargo ship in the Red Sea


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The experts stated that the Houthis have not attempted a genuine drone swarm attack like the ones repeatedly used by Russia in Ukraine. This type of attack could potentially involve multiple threats approaching at the same time. "A swarm attack could overwhelm the defenses of a single warship, and more significantly, it could result in weapons breaching through to target commercial ships," Mercogliano explained.

He mentioned that US warships in the region also have to figure out how to restock their missile inventory. He added, "The only place to reload weapons is at Djibouti (a US base in the Horn of Africa) and it's located near the action."

Possible threats in an evolving battlespace

According to the experts, the deployment of anti-ship cruise or ballistic missiles poses a potentially more daunting challenge. On Tuesday, the Houthi forces reportedly launched three anti-ship ballistic missiles and two land-attack cruise missiles, as revealed by US Central Command.

Anti-ship cruise missiles have the capability to approach from low altitudes and breach a ship's hull above the waterline. This type of weaponry was responsible for the sinking of multiple British ships during the Falklands War, as well as the striking of the USS Stark in the Persian Gulf in 1987," Mercogliano explained. According to him, ballistic missiles could pose an even more significant threat.

"He said that the weapon and its payload could cause significant damage to a warship or commercial vessel when reaching terminal velocity and may require top US interceptors, such as the SM-6, to intercept it. Mercogliano emphasized that the battlespace is constantly changing and that the Houthis will likely have their own tactics to deploy."

Drones versus Warships: The US Military's Response to Houthi Attacks on Maritime Shipping

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'Like the gloves are off': Military analyst reacts after ballistic missiles fired toward US warship


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"The Houthi are watching and seeing how the navies are responding to these attacks," he said.

And the experts say the US may at some point decide it has to go on offense.

"We could take a different approach by targeting the source. Instead of trying to intercept capabilities once they're in the air, we would prevent their use in the first place," Patalano suggested.

"Given the option and ability, it's always more cost-effective to eliminate the archers rather than intercepting the arrows," Schuster remarked.

CNNs Oren Liebermann and Natasha Bertrand contributed to this report.