Hidden details in the video of a US submarine sinking an Iranian warship, according to a WWII expert

• A US Navy submarine sank an enemy vessel for the first time since World War II in combat with Iran.
• A WWII expert told Business Insider the attack looked "remarkably similar" to a 1945 US submarine engagement.
• The video suggests that a Virginia-class submarine carried out the attack before dawn.

For the first time since World War II, a US Navy submarine has sunk an enemy vessel in combat.

Earlier this week, a US Navy fast-attack submarine torpedoed an Iranian warship in the Indian Ocean in an attack that appeared "remarkably similar" to the last time a Navy submarine sank an enemy ship in 1945, World War II battleship expert Ryan Szimanski told Business Insider.

Szimanski, the curator at Battleship New Jersey in Camden, said that video of the attack released by the Department of Defense on Wednesday strongly resembled the Navy's last submarine combat engagement 81 years ago, when the USS Torsk sank two Japanese destroyer escorts with acoustic torpedoes on August 14, 1945.

"Much like what we saw with this ship, or what I believe that I saw with the footage from this ship, the torpedo goes right up their tailpipe, homes in on their propeller sounds, and detonates at the stern of each of those ships, sinking them," he said.

The Navy has not released the name of the submarine that fired the torpedo and sank the Iranian warship, but the video may have provided a clue about the type of sub, Szimanski said.

"My guess is it was a Virginia-class attack submarine that did it because it seems like we're looking through a photonics mast, i.e., a camera on a pole, as opposed to a traditional submarine periscope," he said. The older Los Angeles-class fast-attack submarines typically have traditional periscopes unless they've been retrofitted.

The black-and-white video could offer additional insight into the military action.

"My best guess is it happened before dawn because it looks like we're looking through an infrared lens," Szimanski said. "That's why it's a black-and-white video."

The Department of Defense referred Business Insider to the transcript of Secretary of Defense Pete Hegseth's press conference on Wednesday and declined to comment further. Business Insider also reached out to the US Navy and did not immediately receive a response.

Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, said in a press briefing that the US submarine fired a Mark 48 heavyweight torpedo to sink the Iranian ship. The torpedoes feature a 650-pound warhead and can use both active and passive sonar, or sound navigation and ranging, to hit their targets as far away as 25 nautical miles. The range in the 20-second video released Wednesday suggests a much closer range and shows the submarine's position broadside.

Szimanski said the video appeared to indicate the use of an acoustic torpedo, a move straight out of World War II.

"When you would fire an acoustic torpedo, typically your boat would be stopped and dead quiet," he said. "You fire this torpedo, and it will go for the nearest sound source. My guess is our submarine could hear them so well on passive sonar that they fired the torpedo using sonar, knowing it was going to be able to score a hit."