Tom Housden
The sinking of an Iranian warship in international waters off the coast of Sri Lanka is the first time since World War II that an American submarine has attacked a surface vessel. It also represents a dramatic widening of the scope of combat operations in the five-day-old war.
The Iranian Navy frigate IRIS Dena was sunk by a torpedo fired from a US submarine off the coast of Sri Lanka, whose navy on Wednesday said it had recovered 87 bodies and rescued 32 people
The ship sent a distress signal requesting assistance about 6am (12 pm AEDT), Sri Lanka’s Foreign Minister Vijitha Herath told parliament. Ships and planes were dispatched on a rescue mission and found an oil patch and life rafts, along with 32 survivors and 87 bodies.
The rescued Iranians have been taken to a hospital in the southern Galle district, a Sri Lankan Navy spokesman said. One of those rescued is in critical condition, and seven are receiving emergency treatment, a senior Health Ministry official said.
Defence Secretary Pete Hegseth said the US had “sunk an Iranian vessel that believed it was safe in international waters” – comments that underline how the US-Israeli military operation is stretching far beyond Iran’s borders, and likely to stir debate over the legality and ethics of the attack.
There are also questions over what degree of protection the Iranian vessel had, including whether it was equipped with any anti-submarine detection equipment or countermeasures. The frigate was more than 3000 kilometres from Iran when it was struck, though it was about 30 hours away from the strategically vital US airbase of Diego Garcia.
US President Donald Trump has said one of the key objectives of the war is to wipe out Iran’s navy.
How did the US sink the IRIS Dena?
A video released by the US Department of Defence on X showed the moment of the torpedo attack.
The Iranian ship appears to have been hit by a huge underwater explosion, causing it to lift out of the sea and break apart, as a large plume of water rises into the air.
American boats are typically armed with Mark 48 heavyweight torpedoes, which carry 294 kilograms of explosive and are designed to explode beneath the target’s keel, creating a shock wave that severely weakens a ship’s hull or even snaps it in two.
Australian submarines also carry the Mark 48, and in 1999, the retired destroyer HMAS Torrens was sunk by the Collins-class boat HMAS Farncomb in a spectacular live-fire exercise.
The strike is believed to have been carried out by one of the US Navy’s nuclear-powered attack submarines. Hegseth described it as a “quiet death” for the Iranian navy vessel.
The US has about 50 fast-attack boats in three classes, Los Angeles, Virginia and Seawolf. Because of their nuclear propulsion and design, all are extremely quiet – intended to tail enemy vessels without being detected.
It is not clear which submarine fired the torpedo at the IRIS Dena.
The US has also struck – but didn’t sink – the Iranian drone carrier Shahid Bagheri – essentially a converted container ship with a launch ramp, according to US Central Command.
Hegseth also mentioned on Wednesday that US forces had also sunk Iran’s “prize ship, the Soleimani” – likely a reference to one of an estimated four Shahid Soleimani guided-missile catamarans named after the Iranian military leader Qassem Soleimani who President Donald Trump assassinated in his first term.
Earlier this week, satellite images revealed smoke pouring from the Iranian Navy’s largest vessel, the IRIS Makran, and the apparent destruction of another frigate, the IRIS Draghi, in port.
Why was the IRIS Dena near Sri Lanka?
The ship was apparently heading back to Iran from a joint military exercise off India’s eastern coast.
According to the London Telegraph, the ship’s commanders had attended a naval conference in India along with US naval chiefs before it was torpedoed on its return journey.
The New Indian Express newspaper listed the IRIS Dena among the vessels attending the International Fleet Review and Exercise MILAN in Visakhapatnam last month, “bringing together representatives from around 74 countries for a ten-day maritime engagement off the eastern seaboard”.
How much did the IRIS Dena cost to build?
While its construction costs are unknown, the IRIS Dena was one of Iran’s newer warships, launched in 2015.
It served as a deep-water patrol ship and was armed with heavy guns, surface-to-air missiles, anti-ship missiles, and torpedoes. It carried one helicopter.
According to the defence news website The War Zone, Iran’s Moudge-class frigates, which were reverse-engineered from the earlier British-built Alvand-class, are among Iran’s most modern and capable surface combatants.
The ship had been sanctioned by the US Treasury Department in February 2023, along with eight executives of an Iranian drone manufacturer that supplied weapons to Russia for use against civilian targets in Ukraine.
How many ships does Iran have left?
At least 20 Iranian naval vessels have been sunk during the ongoing war, Admiral Brad Cooper, who leads the American military’s Central Command, said on Wednesday.
While the US hasn’t given a full accounting of its attack on the Iranian Navy, prior assessments suggest the country has many more vessels and assets left.
A US Defence Intelligence Agency report from 2019 – the latest unclassified US assessment available — lists more than 200 weapons-carrying vessels for the Islamic Republic of Iran Navy and the Islamic Revolutionary Guard Corps Navy, which primarily operates within the Persian Gulf.
“The exact numbers for many Iranian small boat types are unknown, but the IRGCN has hundreds of small boats throughout the Persian Gulf,” the DIA report said.
That estimate includes three fast-attack submarines, one coastal sub and 15 midget submarines, as well as around eight corvettes and 100 fast-attack and patrol craft armed with anti-ship missiles and torpedoes that have previously harassed tanker traffic in the region.
What happened in World War II?
Submarine warfare came of age during World War II, with major battles fought for control of strategically vital shipping lanes in the North Atlantic and Pacific Oceans.
But Hegseth’s initial claim that the sinking of the IRIS Deena was the first time a submarine had sunk a ship since that time was incorrect.
Decades later, in the 1971 Indian-Pakistan War, a Pakistani Daphne-class submarine sank the Indian frigate Khurkri, while the Falklands War of 1982 saw British nuclear submarine HMS Conqueror open fire on the Argentine cruiser ARA General Belgrano, killing 323 sailors.
A smaller South Korean Navy ship, the Cheonan, sank in March 2010 after a North Korean submarine attack, resulting in the loss of 45 lives.
With AP, Bloomberg
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