Iran says it has deployed small submarines to act as an “invisible guardian” of the Strait of Hormuz amid a series of rejected peace deals between Tehran and the US. 

The Islamic Republic has at least 16 of the Ghadir-class midget submarines, according to the International Institute for Strategic Studies. Each has a crew of fewer than 10 people and can carry either two torpedoes or two Chinese-designed C-704 anti-ship cruise missiles.

But they are noisy compared with most modern submarines, according to a person familiar with the matter, who requested anonymity because of the sensitivity of the matter. Their crews also have limited experience and the vessels are known to have maintenance issues, the person said.

Tehran has been able to exert control over Hormuz largely through the use, or simply the threat, of missiles and cheap drones, and the so-called midget submarines would likely serve a similar purpose.

One challenge when deploying them effectively is geography: the Strait of Hormuz is only about 100 metres deep at the most. The Persian Gulf is not much deeper. That makes it harder for submarines to hide, even when stationary, because active sonar can spot unnatural objects. 

According to Tasnim, which is affiliated with the Islamic Revolutionary Guard Corps, the Ghadir is “specifically designed” for the waterway and its shallow depths.