The IRGC Has 23 Submarines in Hormuz. The US Navy Can't Find Most of Them.

Iran operates 20-23 Ghadir-class midget submarines, the backbone of its asymmetric naval strategy in the Strait of Hormuz. Each boat: 29 meters long, diesel-electric, 2 torpedo tubes, crew of 18, and the critical capability that makes them dangerous: they can sit on the bottom in shallow water and wait.

The Strait of Hormuz averages 50 meters deep. Parts of the shipping channel are as shallow as 25 meters. The Ghadir-class is designed specifically for this environment. It rests on the seabed, silent, emitting nothing, invisible to sonar in the acoustic clutter of shallow water traffic. When a target passes overhead, it launches torpedoes or releases mines from below.

The US Navy's anti-submarine warfare (ASW) doctrine is optimized for deep water. The Virginia-class attack submarines, the P-8A Poseidon maritime patrol aircraft, the surface ship towed arrays: all designed to find Russian and Chinese submarines in the open ocean at depth. Shallow-water ASW in a high-traffic commercial waterway is a fundamentally different problem with fundamentally different physics.

Sound behaves differently in shallow water. Thermal layers are compressed. Bottom and surface reflections create acoustic chaos. The noise of commercial shipping (even at 94% reduced traffic) masks submarine signatures. The Ghadir-class exploits all of this by design. It is the mine warfare problem in submarine form: cheap, numerous, patient, and hiding in an environment the US Navy isn't optimized for.

The mine warfare article covered the surface layer of Hormuz denial. The submarine threat is the subsurface layer. Together with the insurance market, they form a three-dimensional denial system: mines on the seabed, submarines in the water column, and insurance withdrawal in the financial system. Each layer reinforces the others.

FAQ

Has a Ghadir submarine attacked a ship in this war?

No confirmed submarine attacks on surface vessels. The submarines' primary role has been mine delivery and intelligence collection. The threat they pose is existential (a torpedo into a VLCC carrying $100M in crude) but the execution has been held in reserve, similar to the Houthi card.

Can the US sink the Ghadir fleet?

Finding them first is the problem. The US has superior ASW technology but the shallow-water environment degrades its effectiveness. MH-60R helicopters with dipping sonar are the best tool for shallow-water ASW but each helicopter covers a small area. Clearing 23 submarines from a strait that's 39 km wide and 167 km long is a methodical, weeks-long operation.

Why doesn't Iran use the submarines offensively?

Because the threat is more valuable than the attack, the same logic that applies to mines and Houthis. A confirmed submarine torpedo attack on a commercial vessel would trigger a US ASW campaign that would eventually destroy the fleet. Keeping 23 submarines hidden and threatening extends the denial effect indefinitely.