News this month that the US Navy had sunk an Iranian frigate wasn’t just another war update for members of the submarine community. It was the word of an unexpected and historic milestone.
The March 4 incident in the Indian Ocean marked the first time an American submarine had torpedoed an enemy vessel since the last days of World War II. Submariners have taken the news with a mix of pride in the Silent Service’s capabilities and regret over the inevitable loss of life.
“It’s an exciting event for submarine personnel to know that we finally were tested in combat, in actual combat conditions, and that everything works the way that it’s supposed to,” said David Johnston, a former submariner and submarine historian who lives in Virginia.
Days into the undeclared war against Iran by the United States and Israel, a Los Angeles-class submarine encountered the frigate, the Dena, off the coast of Sri Lanka as it was returning home from naval exercises hosted by India.
In international waters, the sub fired two torpedoes, one of which sank the vessel, according to the Department of Defense. At least 87 members of Dena’s 180-man crew were killed, and at least 32 were rescued by the Sri Lankan navy. The rest remain missing.
DOD released footage and periscope views that appear to show the vessel lifted out of the water by the blast, then sinking almost vertically. They are the first such images from the last 80 years of US submarine history.
That’s simply because circumstances haven’t produced a reason to use torpedoes and not because the weapon has been de-emphasized in any way, Johnston said.
First US submarine sinking since WWII occurs in Indian Ocean
“It just has never come up,” he said. “But they remain a primary weapon of the submarine service.”
The Naval Submarine Base in Groton and Electric Boat declined to comment on the incident.
Steve Ricard, commander of the Groton chapter of United States Submarine Veterans, polled his members to gauge their reactions.
He said sentiments ranged from pride in the service to relief that the crew is safe to sadness over the loss of life, regardless of the circumstances.
“It is pretty much a consensus from SubVet members here in Groton that the US Navy submarine was performing their duties as ordered,” Ricard wrote in an email.
While few details of the sinking have been released, aspects of the incident have been explored by US and international media.
It’s been widely reported that the submarine in question was the USS Charlotte (SSN-766), a Los Angeles-class boat built by Newport News Shipbuilding in Virginia and commissioned in 1994.
Johnston said he was surprised it wasn’t a newer, Virginia-class sub but said that probably made little difference in how the incident played out. He noted the tactics might have been slightly altered because the older, LA-class boats have traditional optical periscopes, while Virginias use mast-mounted sensors that transfer information to computer screens.
“That may change the way that the boat approaches the target a little bit,” he said. “… I think the fact that they caught it on periscope, caught it on video, was deliberate, but they don’t need to do that anymore.”
Three sailors aboard the Charlotte were members of the Australian navy who were training as part of AUKUS, a trilateral security partnership of the US, the United Kingdom and Australia that will eventually involve Australia acquiring nuclear-powered submarines.
Australian officers have trained at the Naval Submarine School in Groton, the first group graduating in 2024.
The Telegraph, a British newspaper, reported that the three aboard Charlotte were ordered to remain in their sleeping quarters during the attack. But their presence has spurred debate in Australia over whether they were involved by default in the conflict, in which their country has not taken a direct role, according to Breaking Defense, which calls itself the world’s largest news organization dedicated to defense.
Another report, originating from Iran International, a London-based digital news service with reported links to Saudi Arabia, says an Iranian sailor on the Dena called his father shortly before the attack and told him US forces had warned the crew twice to abandon ship.
The Dena’s captain did not allow the crew to leave, and the sailor who made the phone call was among those killed, the report said.
John Padgett of Old Lyme, a retired Navy rear admiral and career submarine officer, said that as a matter of normal practice, a warning would not have come from the submarine.
“If you’re gonna sink the guy, you would go ahead and do it,” he said.
The last time a US submarine sank an enemy ship was Aug. 14, 1945, the day Japan’s surrender ended World War II. The Naval History and Heritage Command website credits USS Torsk (SS-423), a Tench-class boat, with the final kill, a Japanese frigate torpedoed off the coast of Japan. Torsk, which sank another vessel earlier that day, still exists as a museum ship in Baltimore.
At least two other US submarines recorded sinkings the same day: USS Balao (SS-285) and USS Spikefish (SS-404). The latter sank the last Japanese submarine of the war.
US submarines’ role then changed with circumstances. During the Cold War, their primary mission was to seek out and destroy Soviet ballistic-missile submarines before they could launch, and other roles followed, including intelligence-gathering.
In early 1991, during the Persian Gulf War, the USS Louisville (SSN-724), a Los Angeles-class boat built by EB, carried out the first combat patrol by an American submarine since 1945, firing Tomahawk cruise missiles against targets in Iraq.
“Since then, US submarines have launched Tomahawk land-attack strike missiles numerous times in combat,” Johnston said.
Through all of this, no ships have been sunk, at least not by American submarines. But other nations’ subs have done so on a few occasions.
During the Indo-Pakistani War of 1971, the Pakistani submarine Hangor sank the Indian frigate Khukri. Eleven years later, in the 1982 Falklands War, the British submarine HMS Conqueror sank the Argentine cruiser General Belgrano, a former American ship. That was the first-ever sinking by a nuclear submarine. The same year, an Israeli submarine torpedoed a Lebanese refugee boat.
In 2010, the South Korean corvette Cheonan sank after an explosion and is believed to have been torpedoed by a North Korean midget submarine.
By the time of the Dena sinking this month, American torpedo technology had been transformed since the last sinking in World War II. In those days, torpedoes detonated on contact with the target. But the Mark 48 torpedo, in use since 1972 and now carried by all US submarines, is designed to detonate under the keel of a surface ship, destroying its structural integrity.
That was in evidence in the video of the Dena sinking, where the stern appeared to be lifted out of the water.
“It’s incredibly devastating,” Johnston said. “It will break the keel of the ship, devastate any underwater equipment like rudders and propellers.”
As for what the Dena sinking means for the future of submarine warfare, Padgett, a former commander of the Pacific Submarine Force, said he does not expect increased use of torpedoes and does not think the Iranian navy will be much of a factor in the present war.
Writing about the incident in the Jerusalem Strategic Tribune, James Foggo, a retired Navy admiral, and Steven Wills, a naval researcher, note that all of the post-1945 sinkings had significant political ramifications. They contend that, beyond the Iran war, Dena’s fate sends a message to Russia and China, which are investing in their own submarine fleets.
“The sinking of Dena may prompt a return by navies … to the kind of massive antisubmarine warfare exercises last seen in the waning years of the Cold War,” they wrote.
Padgett said he has mixed feelings about the idea that there’s sober satisfaction to be taken from seeing submarine training pay off in actual combat.
“There’s certainly a measure of professionalism, but I don’t think it’s something that everybody is all happy about,” he said.
The training, he said, is done with the goal of deterring a war rather than fighting one.
“Going to war means you screwed up,” he said. “You didn’t do the right thing.”