Why underwater mines could determine trajectory of Iran war

The possibility of sea mines being deployed in the Strait of Hormuz is raising concerns about safety in the strategically vital waterway and sending shockwaves through global shipping markets. Since the war began, at least 14 vessels have reportedly been struck by projectiles in the strait, while Iran’s Islamic Revolutionary Guard Corps has warned that any ship passing through the area could be targeted.

Sea mines could mark another escalation in the conflict. Also known as naval mines, these devices detonate autonomously when ships approach or pass nearby.

Scott Savitz, a senior engineer at the US policy think tank RAND Corporation, explained speaking to the Canadian broadcaster CBC that such weapons generally fall into three categories.

Bottom mines rest on the seabed and are usually triggered by “influence” rather than direct contact, meaning they detonate when they detect ships above them by sensing changes in sound, magnetism or water pressure.

Another type is the moored mine, which is attached to the seabed with an anchor and tether and resembles "a big, spiky ball that's buoyant," Savitz said. The buoyancy allows the mine to float at a certain depth, where it can explode either upon direct contact or when its sensors detect a passing vessel.

A third category consists of drifting mines, which Savitz says "do just what they sound like" — drifting along the water’s surface with currents until they explode on contact with a ship’s hull.

Although drifting mines were banned by the Hague Convention of 1907 unless they become harmless within an hour of release, NATO says they are still used by "rogue states" to disrupt maritime trade and threaten shipping routes.

Savitz said sea mines can potentially sink a vessel or even break it apart, although the extent of the damage can vary widely.

According to him, the severity of the damage depends on factors such as the size of the mine, the depth of the water and the structural resilience of the ship.

Savitz described naval mines as "tremendous disruptors," noting that their impact is often indirect, as they create fear and uncertainty by making ships feel vulnerable to attack at any moment.

He added that the tactic "takes a lot more resources and time to counter than it does to implement."

Savitz said Iran may also hope that deploying mines in the strait would prevent US and Israeli forces from launching an "amphibious" invasion from the shoreline.

Historically, such strategies have been effective. Naval mines were "one of the driving factors behind the US and its allies not conducting an amphibious landing on Kuwait in 1991," he said.

Between 1988 and 1991, three US warships were damaged by sea mines in the region, Savitz noted. Although all remained afloat, they were left unable to continue combat operations.

At the same time, Savitz pointed out that Iran also relies heavily on the strait for its own shipping, meaning that laying mines there would likely not be its first choice. During the Iran–Iraq War in the 1980s, Iran deployed mines elsewhere in the Gulf but avoided placing them in the Strait of Hormuz.

"If there's a perception by the Iranian authorities that they're not going to be able to use that waterway anyway, then maybe they say it's time to deny it to everyone else as well," he said.

Perceived fear heavier than actual physical damage

But the real damage could be economic, according to Rex Brynen, a political science professor at McGill University.

"They don't necessarily need to hit every vessel," he said. "They just need to increase everyone's insurance rates to the point where it's not worth risking the costs of paying the insurance for that super tanker to take oil through the straits."

Brynen says it seems like an "obvious" move to put economic pressure on the US to end the war.

He says while there's "nothing surprising" about Iran deploying sea mines, it is surprising that the US administration wouldn't have prepared for it as an option the Iranians have.

Brynen says it's estimated that Iran has hundreds of sea mines.

Removing mines

Savitz said the most effective method of neutralizing naval mines is a "meticulous" process known as mine hunting. This involves using sonar to detect the distinct shapes of mines underwater before sending specialized devices to disable them.

Another technique is mine sweeping, which involves dragging specialized equipment through the water designed to withstand explosions and trigger mines to detonate safely.

Both approaches are "painstaking" operations and are unlikely to be conducted during active combat, Savitz said.

Experts also warn that unexploded naval mines from conflicts decades ago continue to pose risks in many seas today — raising the possibility that mines deployed now could endanger ships long after the current war ends.

By Nazrin Sadigova