IRIS Dena Incident: The Spotlight and Lessons

by Captain (IN) TSV Ramana (Retd.)*

There is considerable debate and discussion ongoing regarding the sinking of the Islamic Republic of Iran’s ship IRIS Dena. Numerous analysts, former naval officers, ‘strategic affairs experts’, diplomats, and social media commentators have expressed diverse viewpoints on this incident.

Reason for the Spotlight

IRIS Dena participated in the International Fleet Review (IFR) and Milan 2026, hosted by the Indian Navy off Visakhapatnam from 15 to 25 February 2026. It departed from Visakhapatnam on 25 February 2026 and was torpedoed by a United States Navy (USN) Submarine USS Charlotte (SSN 766) on 04 March 2026, at a position approximately 19 nautical miles south of Galle (Sri Lanka).

About IRIS Dena

The Jane’s Fighting Ships 2023-2024 classifies the IRIS Dena as a ‘Jamaran (Mowj)’ class FFGH (Guided Missile Frigate Helicopter). The ship was commissioned on 14 June 2021. The ship has a length of 94.5 m, a breadth of 11.1 m, a height of 4.3 m and a full load displacement of 1372 tons.

Weapons: IRIS Dena’s armament includes:

Four Noor (C-802 A) anti-ship missiles with a range of approximately 180 km.

Four SM-1 surface-to-air missiles with a range of 38 km.

One 76 mm gun with a range of 16 km.

One 40 mm/30 mm gun with a range of 04 km.

Six 324 mm torpedo tubes.

Sensors: The sensor suite includes:

Air/surface search radar Plessey AWS-1.

Surface search radar Racal Decca 1226.

Fire control radar Contraves Sea Hunter

Two Furuno navigation radars.

There are no inputs on whether the ship was equipped with a sonar.

Situation Prior to Departure of IRIS Dena from Iran, for IFR and Milan 2026

IRIS Dena is based at Bandar Abbas (Iran). The ship arrived off Visakhapatnam on 17 February 2026. The distance from Bandar Abbas to Visakhapatnam is approximately 2728 nautical miles. The ship would require between 8 and 10 days for the transit from Bandar Abbas to Visakhapatnam. Therefore, the IRIS Dena should have departed Bandar Abbas between 07 and 09 February 2026.

The United States had begun a significant build-up of its forces in the CENTCOM AOR from mid-January 2026. Therefore, when this ship departed Iran, tensions between the United States and Iran were already increasing. Iran, consequently, would have known that this ship was leaving at a time when the regional situation was prone to become volatile and dangerous. In such circumstances, is it logical for Iran to send this ship without armament or with only limited armament? No professional navy would likely do such a thing.

Situation After the Departure of IRIS Dena from Visakhapatnam

IRIS Dena departed Visakhapatnam on 25 February 2026, after participating in the IFR and Milan 2026 events. On 28 February 2026, three days following the departure of IRIS Dena, the United States and Israel launched strikes on Iran as part of Operation Epic Fury. Would the ship have been unaware of this development? This seems highly unlikely.

IRIS Dena, subsequently, continued to remain at sea. There are no credible inputs to ascertain what was going on between the authorities in Iran and the Commanding Officer of Dena, or the reasons that prompted this ship to stay at sea until 04 March 2026, when it was struck by a torpedo from a US Navy SSN.

Actions by Other Iranian Ships that Participated in IFR and Milan 2026

Incidentally, Dena was not the only Iranian Navy unit to participate in the IFR. The flotilla also included Hengam-class Landing Ship Lavan (displacement of 2581 tons) and Bandar Abbas-class replenishment ship Bushehr (displacement of 4673 tons).

Lavan sought permission to enter Kochi on 28 February 2026, which was granted on 01 March 2026. The ship subsequently entered Koch on 04 March 2026 and has remained there since. Bushehr requested permission from Sri Lanka to enter Colombo on 04 March 2026, and the ship was granted permission on 05 March 2026. It was eventually taken to Trincomalee by Sri Lankan authorities.

Incidentally, Dena was the lightest of the three Iranian ships, with a displacement of 1372 tons, while Bushehr was the heaviest at 4673 tons, and Lavan was the second heaviest, displacing 2581 tons. It seems inexplicable that, while two of the larger Iranian vessels sought refuge in India and Sri Lanka respectively, the smallest of them, Dena, remained at sea.

US Navy SSN Strike on IRIS Dena

The strike by the US Navy SSN on Dena on 04 March 2026, involving a Mk 48 Torpedo and the subsequent release of the periscope photographs and videos of the attack, sparked considerable debate on various aspects, including legal, moral, humanitarian, diplomatic niceties, and sensitivities of relevant countries.

Was the strike on Dena by the USN Navy SSN illegal? It does not appear to be the case. The United States and Iran were already engaged in high-tempo combat as of 04 March 2026, and both countries were belligerents. Therefore, if one belligerent encounters a unit of the other, it is operationally logical to attempt to neutralise that unit. That is precisely what the US Navy SSN seems to have done.

Was there any problem with the location where Dena was struck? Again, the location of the strike, 19 nm from Galle (Sri Lanka), does not pose any legal quandary.

Has the US extended the warzone to the rest of the IOR by this strike on the Dena? This seems to be a slight exaggeration, as the chances of the United States and Iran engaging in a shooting match in far-flung areas of IOR in the near future seem to be practically negligible.

Was this strike by the US a pre-planned operation, or did Dena present itself as a target of opportunity? It is difficult to arrive at a firm conclusion on this, as both events are possible. Does it make a difference if it was a pre-planned operation? The chances that the US was tracking the three Iranian units are highly likely, and one need not be surprised by this.

Should the US SSN have surfaced after the attack to pick up the survivors from Dena? The answer to this can be varied. However, it is a fact that no submarine, especially in a combat situation, would attempt to surface in an operational area. It is impractical to expect it to do so.

Should the United States have considered the ‘optics’ that would be generated by this strike, considering that the Dena was returning from a high-visibility event in India, and therefore, kept India in the loop about its intention?

It is unrealistic to expect a country that is engaged in war to reveal its combat plans to another country, irrespective of how good or bad the current state of relations is. Further, considering that a submarine was to execute the strike, it is impossible that the United States would be willing to reveal the fact that one of its nuclear submarines was operating in the Indian Ocean. Entities in India, who saw this probable lack of communication from the US as some kind of an affront to India and a lack of concern for its sensitivities, need to rethink their approach.

Would it have been good if the US had kept India in the loop? It is a tricky question, since India would then become de facto complicit in the strike on the Dena and thus a participant in this war between the US and Iran.

A ‘zero-sum’ mentality is not a good approach, especially when the world is in a state of flux and both the current situation and the future seem uncertain.

Alternative Hypothetical Scenarios

Scenario 1: Suppose the US strike on Dena occurred somewhere in the Northern Arabian Sea. Would it still provoke the same reaction from various entities in India? Or would the distance and the passage of time lead to a different, more subdued response?

Scenario 2: Let’s assume that Dena was not a participant in the IFR and was operating in the region for another purpose. Then, would a US strike on this ship, at the same time, in the same manner, and in the same position, be viewed differently?

Scenario 3: Let’s assume that Dena was returning from a visit to another country in India’s neighbourhood and was then struck in a similar fashion, with all else remaining the same. What would be the reaction of all those who are currently critical of India?

Comments

Excessive attention to the fact that IRIS Dena was returning from IFR at Visakhapatnam and use of phrases like ‘it was a guest of India’, ‘it happened in India’s backyard’, ‘the US did not take the bad optics into consideration’, ‘the US should have kept India in the loop’, ‘the sailors from Dena had engaged in friendly interactions’ ‘Dena was not armed’ etc seem to have attempted to somehow make India, responsible in some way for this incident, while conveniently forgetting that the US and Iran are at war.

While it is but natural to be sentimental about this tragedy, it is also simultaneously true that warships are designed to, and expected to go into harm’s way. An analysis clouded by sentiments is not the way for dedicated naval professionals; it may be the preserve of others.

There were attempts to state that the Indian Navy should have been aware of the deployment of the US SSN, thereby implying that it should have been monitoring every activity in the IOR, 24x7x365 days. It is clear that the people making such statements have no idea of the sheer size and complexity of the maritime domain, where nothing is ever static.

Lessons

The most significant lesson from this incident is that assessment of the strategic situation in the vicinity of one’s own country, and also in the vicinity of the areas where one’s warships would operate in the near future, has to be a 24x7x365-day affair. One cannot be caught by surprise, either due to a lack of necessary intelligence or, more dangerously, due to ignoring that intelligence.

For a warship, there is no such thing as a ‘ceremonial role’; even when on diplomatic or ceremonial missions, it is always prepared for war.

The narrative trend on ubiquitous social media must be monitored continuously, and false and damaging narratives must be countered immediately and effectively. There can be no delay in this, and it must be carried out by trained professionals, not merely as an additional task.

Any war or combat operations happening anywhere in the world must be closely monitored with adequate resources, especially regarding manpower, and the implications for the country must be continuously evaluated. The distance of the theatre of war from our own country must not cause complacency in any way.

*****

* Captain TSV Ramana (Retd.) is a former Indian Navy Officer and a pioneer of the Indian Navy’s analytical studies vis-à-vis China, with extended tenures in the Directorate of Naval Intelligence at Naval Headquarters, the China Cell at the National Maritime Foundation, at the Maritime Doctrine and Concept Centre (MDCC) as part of the ‘Strategic Maritime Assessment Team (SMAT) – China’ and the Centre for Contemporary China Studies (CCCS). He is a qualified Mandarin interpreter from the School of Foreign Languages at New Delhi. The views expressed are his own.