Sinking the `Dena'. An audacious Iranian gamble that failed.

I decided to write this, as the narrative in the Indian media gives the impression that the Iranian warship IRIS Dena (Islamic republic of Iran ship DENA) was invited to India for the international fleet review we hosted and on departing, ship was sunk by a US submarine. It has been alleged that the sinking of an unarmed ship, with mostly cadets under training, was a war crime and a snub to India, since the ship was `under our protection’. At the least it questions our credentials in being the guardian of the Indian ocean, or allowing our `guest’ to be killed in cold blood.

I have a different view and one not speculated on by the media. I think it was an audacious and high risk gamble by the Iranian navy, to target US merchant shipping, in the event of war. That gamble failed. The gamble involved 3 Iranian warships (not just the IRIS Dena) that were deployed far from home waters, to carry out what might have been a surprise attack on US supply or merchant shipping, in an unexpected area.

Background. Iran’s strategic dilemma
Ever since the 12 day war of 2025, there was a strong possibility that the US and Israel would attempt to secure a deal that would rid Iran of its uranium enrichment, its ballistic missiles and its support for proxy forces like Hezbollah, Hamas and the Houthis and if that deal was not forthcoming, there would be war. Coercive diplomacy was accompanied by a build up of US forces. If the US and Israel were to attack, it would be at a time of their choosing and by surprise.
Iran was too weak to absorb a `first strike’ or to fight an atrition war.

Iran’s choice would be to either attack pre-emptively (a high risk gamble) or do nothing, which has lower risk of something bad happening today, but the inevitability of slow strangulation in the longer term. It is akin to the choice before a concentration camp inmate. Join other prisoners in a revolt now, which will bring certain death if the revolt fails (particularly if others don’t join in), or do nothing and accept that you will slowly die – albeit with a marginal chance of survival at the end. Game theory suggests that a country will invariably opt for the safer option, even if it means slow strangulation in the longer term. An exception was Israel’s pre-emptive strikes that began the 1967 six day war.  

In this context, for the Iranian navy, whose assets are under constant surveillance, doing nothing would mean that the major surface ships of the Navy would almost certainly be destroyed in the event of a war where the enemy strikes first, without being able to inflict corresponding damage on the enemy.

The Iranian Navy’s weakness. The Iranian armed forces are divided between the regular Army (and Navy and Air force) and the Revolutionary guard. The guard has its own air force, navy and special forces. While the Army and Navy operate as a reasonably professional force, the Revolutionary guard is designated a terrorist organisation and has a focus on irregular warfare and partnering with groups like Hamas, Hezbollah, the Houthis and Iraqi Shia militia.  

The regular armed forces are also under funded compared to the Revolutionary guard (IRGC). The clerics running Iran may want a conventional navy with ocean going vessels, a modern air defence system and modern fighter aircraft, but they lack the funds. Funds that are sanctioned might get diverted to the IRGC Crippling sanctions have meant lack of parts for maintenance of western equipment, or poorer quality local substitutes. The result has been platforms that look good on paper (in an effort to please the clerics) but won’t survive the test of modern combat. An example is the 42,000 tonne drone carrier, or the 100,000+ tn logistics ship. Both are converted from merchant ships, with little protection, no escorts and no sensors that a modern warship has.

In the event of war, the Iranian navy has the role of closing the strait of Hormuz. This would largely be done by smaller ships, mines and shore based drones and missiles, with the IRGC playing a lead role. The regular Navy with its conventional surface fleet would be tasked with attacking enemy further away from the Strait of Hormuz. If it was assessed that the fleet would have little chance of surviving a US first strike, an Iranian Navy planner would have to look at unconventional ways to hit enemy shipping, even if it meant the attackers had little chance of surviving.  

The possible Iranian plan:
3 ships were to sail from Iran, to the waters south of Sri Lanka, astride the main merchant shipping route from the Malacca straits to the Middle East. These ships were:
The Dena – Iran’s most capable warship. Part of the four ship Moudge class, built from 2010.
The Dena was the third of four, commissioned in 2021.  This carried more advanced and heavier armament than the other three ships of this class.

The  Lavan – A landing ship built in 1974. A near obsolete ship with no weapons, which would not normally pose a threat to other ships. However, the Lavan was modified to carry long range drones. This was demonstrated in an Iranian naval exercise in 2022.

The Bushehr. A support vessel. The only other vessel of its class was undergoing a refit when war broke out. It’s presence was necessary to supply other ships in any extended operations away from home waters.

The Dena had 1500 tonnes had a limited capacity extended operations at sea and therefore had to be accompanied by a tanker. In 2022-23 The Dena, along with a tanker, circumnavigated the world showing for the first time that the Iranian navy was capable of extended operations.

Most (three of the four Moudge class and one of their two Lavan class) of their ships capable of operating away from home waters were undergoing refits, or not suitable for immediate operations when war broke out. Three of these four were destroyed on the first day of the war.  

If the three ships (a large part of the fleet capable of `blue water’ operations), sailed from home waters, for no apparent reason, when war seemed imminent, they would be tracked as soon as they left port. The only way Iran could justify the voyage of these ships was:
The Dena and Lavan were invited for India’s fleet review and MILAN exercise in Vizag from 17^th Feb. 
The Bushehr was also part of this exercise, though no not officially listed as participating. 

Thus, close to the outbreak of war, the three Iranian ships most capable of operating away from home waters, left Iran. All of them sailed to India, ostensibly for goodwill visits.

Should war break out, the three ships would be well placed to interdict US shipping, on two routes.
- From the Malacca straits to the middle east, passing just south of the Sri Lanka coast (Dondra Head)
- From the South Indian ocean to the Middle East, including the US base at Diego Garcia.  

Between 110-120 ships pass close to the southern coats of Sri Lanka daily. This is a major sea lane.
There are at least 2 US owned or US flagged merchant ships passing just south of Sri Lanka daily.
In addition, ships with a neutral flag (Panama or Liberia) might be charted to carry military supplies to Middle eastern ports.

Chinese satellites might provide the Iranian ships with the location and course of ships that can be potentially targeted . There would be information on the cargo carried by ships flying flags on convenience.

The plan might have been for the Iranian ships, once war broke out, or were given the orders, to seek out and destroy US merchant ships, or ships carrying US material, before they were engaged and destroyed, or sought refuge in a neutral port. It was reasonable to expect that within a week,
such targets would be available, should the US be unaware of the danger.

The US on their part, would be expected to track the Iranian ships once they left India – by satellite, or P8 aircraft, or submarine. Either merchant shipping would be diverted away, or a convoy of ships escorted by the US Navy, or, if war broke out, the Iranian ships would be engaged and destroyed.

Irrespective of success of failure, the Iranian ships would probably be at sea for no more than a week before being destroyed, or being interred in a neutral port.

The facts:
The IRIS Dena and Lavan left India on 25th Feb (before the war) after completing the exercise on 24^th.  The Dena reached the Sri Lankan port of Hambantota on 26^th Feb. The Dena was offered a safe harbour in India, after the MILAN exercise, as war clouds drew near, but was it was declined.

All three ships had on 26th Feb, requested docking permission in Sri Lanka from 9^th to 13^th Mar. It was not known then that the conflict would start on the 28th.  

The movements of the Dena was unknown from 26^th till the 3rd of March when it asked permission to dock in Sri Lanka. It was sunk 11 hours later, on the morning of  4^th March.

The Lavan left India on 25^th and on the evening of the 28^th asked for permission to dock in India, citing engine trouble. The permission was given on 1^st March, but the ship arrived in Kochi on 4^th March, after the sinking of the Dena. 

The Bushehr also asked for permission to dock in Sri Lanka, citing engine trouble, on the 4th of Mar, after the Dena was sunk. It was stopped off Colombo, the crew removed and the ship sailed to Trincomalee. 

The whereabouts of the ships were unknown from 26^th Feb to 3^rd Mar (5 days). 

On the 1^st of March, Iran fired 4 ballistic missiles at the USS Abraham Lincoln led carrier battle group., operating off the sea of Oman about 350 km south of the Iranian coast. The IRGC announced this launch. The firing of these missiles by themselves could not hope to accomplish anything (though social media suggested otherwise) since a ballistic missile cannot hit a moving object. However, it may have drawn the attention of the US Navy to the presence of the three Iranian ships. A classic case of the left hand (IRGC) not knowing what the right (Iranian Navy) was planning to do. A situation exacerbated by the breakdown of command and control after the first US-Israeli attacks against the Iranian leadership on 28^th Feb.

Also on 1^st March, a Marshall islands flagged oil tanker was hit by an Iranian sea drone, killing one crew member.

The effect of these missile launches was to push the Lincoln battle group further south and closer to the Iranian warships and more actively hunt for Iranian ships.

On 28^th evening (after war broke out), the IRIS Lavan asked for permission to dock at Kochi citing an engine problem. Permission was given on the 1^st but the ship only turned up at Kochi on the 4^th.
It is possible, the Lavan had spent the time between 28^th Feb and 3^rd March seeking out US ships.

On the 2^nd of March, Iran’s largest warship, the 42,000 Tn large drone carrier Shahid Bagheri was hit and possibly sunk. The Shahid Bagheri was the size of an aircraft carrier – a conversion from a container ship. The attack on the Shahid Bagheri underscored the futility of the Iranians trying to
operate against the US Navy when under heavy surveillance. It was a `poor man’s aircraft carrier’ with no escorts, no protection against attack, no doctrine around its use and under constant surveillance. It represents all that was wrong with Iran trying to build a surface fleet.

Their only hope was a sneak attack from an unexpected direction, which is what I think the Dena and Lavan may have been tasked with.

It might have been clear at this stage that IEIS Dena and Lavan were not going to fund targets and we at risk of being hunted down. On the 3^rd of March, the Dena requested permission to dock in Sri Lanka (permission was earlier given for all three ships to dock in Trincomalee from 9-13^th Mar) while the Lavan proceeded to Kochi, having already obtained permission to dock on 1^st Mar.
The Dena was sunk on the morning of the 4^th by the USS Charlotte, a Los Angeles class nuclear attack submarine (SSN).

The support ship Bushehr sought permission to dock in Colombo on 4^TH Mar (instead of Trincomalee from 9^th  Mar which had been approved pre-war). Approval to dock in Trincomalee was given and the ship docked on 5^th March.

If the Iranian ships were unarmed:
Once war was imminent and if the ships were unarmed as it claimed, the IRIS Dena could have:
- Made for an Iranian port at high speed (at 30 knots, it would have taken 2 days to reach an Iranian naval base from Hambantota 1400 nautical miles away) OR,
- Request shelter at a neutral port in Sri Lanka or India. During the MILAN exercise in India, with the possibility of war, India had offered the Dena the possibility of sheltering in India. That offer was not taken up.

It was claimed that the ship was full of cadets under training. It was in fact the Bushehr that was on a training mission, carrying a crew of 208 instead of its normal compliment of 59. Of the 208 crew, 84 were listed as `officer cadets’, apart from 53 other officers. The Bushehr was officially on a training 
cruise. The Bushehr visited Mumbai in 2025, on a training cruise. 

The Dena, which at 1500 tons was too small to accommodate crew for training, had 180 on board when it was sunk, against a minimum of 140 needed to operate the ship. Iranian ships are believed to have a higher number of crew compared to western ships for the same class of ship.

Once fighting broke out on the 28th, the Lavan requested shelter in Kochi, but not the Bushehr or 
Dena. One wonders what their orders were. The ships could have tried to sail back to Iran hugging the 
Indian and Pakistani coasts, or, once news of attacks on Iranian ships came in, immediately sought shelter at an Indian port - Kochi, Karwar or Mumbai. Their movements between 26th Feb (Hambantota) and 3rd March are unknown, but it was not on the shortest route to Iran, or the safest (up the Indian coast).    

The rest of the Iranian navy.
Of the remaining three ships of the Moudge (Dena) class, two (the IRIS Jamaran and Sahand) were sunk at their port in Iran, on the first day of the war. The third is based in the Caspian Sea. One of Iran’s four older Alvand class frigates was also sunk. Commissioned in the 1970’s, this was probably the only one still operational.  

Apart from the Shahid Bagheri mentioned earlier, their largest ship by tonnage, the Makran was sunk on 1^st March.  Their latest ship – the Zagros, a signals monitoring ship, was also sunk on 1^st March.

Also sunk at the beginning of the war were Iran’s only operational coastal submarine – the Fatah
(commissioned in 2019). The only operational Kilo class (ocean going) submarine and the Sayyid Shirazi – a new missile catamaran corvette, along with two of Iran’s three older corvettes.

Had the Dena not sailed to India, it would simply have been sunk in Iran.

India's role: India's role ended once the Dena and Lavan left Indian waters (25th Feb). 
The ship was sunk in International waters. Not just outside Indian territorial waters, but outside 
our EEZ. 
The Lavan, which had requested to shelter in India on 28th Feb, was given that permission less than a day later. It turned up on 4th March. The Dena was also proactively offered shelter in India, before the outbreak of war, which was declined at the time. 

India does not track submarines in International waters, particularly those of friendly countries., It is also unlikely that a Los Angles class sub can be tracked unless we actively look for it - we do not actively look for submarines far from our shores in peacetime.   

Was it `murder':
The submarine is not obliged to warn a ship before it is attacked, or to rescue survivors if it means giving away its position and putting itself in danger. While I do not believe the war that the US and Israel started to be legal (under both US and International law), once it had started, the crews of the Iranian ships had to expect, 4 days after war started and most of the major ships of the Iranian navy sunk, that they would be targeted. 

We only have a statement from an Iranian spokesman that the Dena was unarmed. The Indian navy does not say so. That same spokesman was most likely incorrect in saying the Dena had cadets on board, when in fact it was the Bushehr that was the training ship.