Technical analysis of the sinking of the IRIS Dena warship by a Mark-48 torpedo.
The US Navy confirmed sinking the Iranian frigate IRIS Dena in the Indian Ocean with a Mark-48 torpedo, revealing a critical weakness in its anti-submarine defense capabilities.
On March 4, US Secretary of War Pete Hegseth confirmed that a US Navy submarine had launched a torpedo that struck and sank the Iranian warship IRIS Dena in international waters of the Indian Ocean. The incident occurred off the southern coast of Sri Lanka as the ship was returning from participating in the International Fleet Review 2026 (IFR 2026) and the MILAN exercise in the Bay of Bengal.
IRIS Dena's multi-mission combat capabilities
IRIS Dena is a Moudge-class missile frigate designed and built domestically by Iran, representing Tehran's efforts to develop its domestic defense industry. The ship has a displacement of approximately 1,300-1,500 tons, is nearly 95 meters long, and reaches a maximum speed of about 55.6 km/h thanks to its powerful four diesel engines.
In terms of firepower, IRIS Dena is equipped with a diverse weapons system including a 76mm Fajr-27 naval gun, Noor/C-802 anti-ship missiles, Sayad-2 anti-aircraft missiles, and 324mm torpedo tubes. The ship uses a 3D Asr radar with a detection range of up to 300km, allowing it to track multiple targets simultaneously. However, military experts believe that the anti-submarine capabilities of the Moudge-class submarines are limited due to the lack of a modern towed sonar system, making the ship vulnerable to new-generation attack submarines.
The power of the Mark-48 torpedo
The weapon that directly sank IRIS Dena was the Mark-48 (Mk-48) heavy torpedo, a strategic weapon on US Navy attack submarines. The Mk-48 weighs approximately 1.6 tons, carries a high-explosive warhead of nearly 300 kg, and is capable of traveling at speeds exceeding 101.86 km/h.
The Mk-48's distinguishing feature lies in its target destruction mechanism: instead of direct impact, it typically detonates under the hull to create a massive pressure bubble. When this bubble collapses, the pressure difference can break the hull structure in seconds. In a real combat environment, the combination of the submarine's stealth capabilities and the Mk-48's guidance technology created a decisive advantage over the IRIS Dena's sensor system.
This attack not only inflicted heavy losses in terms of human lives and equipment on the Iranian Navy but also demonstrated the technological gap in underwater warfare between the two forces.