A familiar-looking Houthi torpedo could be derived from captured US tech, analysts say

• The Houthis unveiled a new torpedo, nicknamed Calamity.
• The weapon resembles a US sea drone the group captured years ago, analysts told BI.
• There are prior examples of US weaponry being turned against it, with help from Iran.

The Houthi rebels in Yemen have a new torpedo to show off — and it looks familiar.

The militant group published videos on Sunday and Monday touting its new weapon, named Al Qar’iah, or “Calamity.”

The Yemeni group is not known for its technical daring; and experts assessing the video saw echoes of captured US weaponry, a naval drone that was taken whole in 2018.

Without assessing one in detail, it is impossible to say how the Calamity came to be.

But it would be in keeping with other examples of US equipment being reverse-engineered into the arsenals of its foes, especially those tied to Iran.

Martin Kelly of the UK advisory firm EOS Risk Group, said the torpedo could derive from a US REMUS 600 drone lost in 2018.

Footage the group released around the time the waterborne drone was lost appears to show them seizing it, with names of Western defense companies still visible on its body.

Per Kelly, Iranian scientists could have turned a captive example into a “blueprint” for the homegrown weapon seen this week.

Tehran’s copyshop

“Iran probably reverse-engineered the REMUS 600 and sent the parts back to the Houthis for construction,” Kelly told BI.

Iran provides significant security support to the Houthis, like weapons, training, and intelligence support, and is even its primary provider, which has allowed it to hit land and sea targets.

Mohammed Albasha, a US-based Middle East security analyst, reached a similar conclusion.

He told BI that Iran has a history of reverse-engineering captured US technology. He cited the Toophan missile, derived from the US BGM-71 TOW, and the Mersad air defense system from the US MIM-23 Hawk.

Another significant example is the Shahed drone, derived from the US RQ-170 Sentinel. Shaheds have been used extensively by Russia in its invasion of Ukraine, the fruits of its alliance with Tehran.

Iranian-provided weapons have loomed large in recent Houthi attacks on the Red Sea.

The US Defense Intelligence Agency assessed in July that the Houthis used Iran-supplied weapons in more than 100 attacks.

It said that the US and its allies intercepted at least 20 Iranian vessels between 2015 and 2024 carrying illicit technology like missile components, drones, and other weaponry bound for the Houthis.

Experts weren’t unanimous in their assessment of the drone.

Farzan Sabet, a senior research associate at the Geneva Graduate Institute, saw a different possible origin.

He told BI that the torpedo looked like models put on display at an Iranian navy exhibition in Tehran in December 2023.

He said other features of the torpedo didn’t match the REMUS 600.

He also said that it was possible that the Calamity’s makers took some pointers from the captive drone without wholesale remaking its functionality.

The torpedo was likely “much simpler” than any US forebear, he said.

Exploiting vulnerabilities

It is yet to be seen what difference a new torpedo could make to the Houthis.

The group already uses a variety of one-way attack drones, naval drones, and anti-ship missiles to target commercial ships and US warships in the Red Sea.

The strikes are part of a campaign to exert pressure on Israel and the West since the beginning of the war in Gaza.

Between November and June, the Houthis attacked or threatened the US Navy and other vessels over 190 times, according to the Pentagon.

The attacks have disrupted global shipping, adding risk to a pivotal route. Freight rates doubled to nearly $4,000 per container in January and then jumped to over $5,900 in July, according to maritime research consultancy Drewry.

Rates as of this writing were roughly $3,095, compared to an average of $1,300 per trip in October last year, per Drewry’s index.

The US Navy and allied navies diverted significant resources to counter the Houthis and increase confidence in the route.

Albasha, the analyst, said the Calamity looks too small to seriously bother a heavily armored US warship.

However, even a small torpedo can do harm if it hits right.

“A well-placed strike can cause critical flooding, disable essential systems, or impair the ship’s ability to maneuver, forcing it out of action,” he said.

“Though unlikely to sink a warship, such attacks can render it temporarily inoperable, impacting fleet operations and morale.”