The Strait of Hormuz: Iran appears to have planted several sea mines in this strategically and economically important strait. Even a small number of mines can lead to a complete standstill of shipping here. Image: keystone
Iran may have laid sea mines in the Strait of Hormuz. What types of this dangerous weapon are there and how do they work?
Mar 14, 2026, 7:53 p.mMar 14, 2026, 7:53 p.m
Sea mines are bodies filled with explosives that are placed in water and explode on contact or when a ship approaches. Like land mines, sea mines are a cheaply produced weapon that can make crossing a certain area so dangerous that it is effectively closed. In military jargon they are therefore referred to as “barrage weapons”.
The explosive charge of sea mines contains TNT (trinitrotoluene), which is insoluble in water and remains effective for decades, so old mines can still be explosive. Mines can contain an explosive charge of up to 1.5 tons.
Current there are reportsaccording to which Iran, the has an extensive arsenal of various types of sea mines has, several of them in the strategically important Strait of Hormuz has relocated. These mines are used to block ports, close sea areas or, as here, make shipping routes impassable. They are considered difficult to detect and eliminate.
What types of sea mines are there?
Sea mines can be divided into different types according to the way they are positioned or the type of detonator they use. Most of these conventional mines can be laid in up to 60 meters of water.
Igniter type
- Contact igniter: These detonators are triggered when the ship’s hull touches the mine. The method can be mechanical, chemical or electrical.
- Distance fuze: They react to changes in the earth’s magnetic field generated by large ship hulls; to the noise of screws or the water pressure caused by a passing ship. Modern mines can even allow a certain number of ships to pass by and only detonate later. In this way, they make eviction more difficult.
positioning
A sea mine can be placed at the waterline, float between the waterline and the seabed, or be on the seabed. Accordingly, a distinction is made between drift mines, anchor mines and ground mines:
- Drift mines: They are unanchored sea mines that are equipped with contact fuses and can be easily laid. They float freely in the water and move with the current and wind; their movements cannot therefore be predicted over a longer period of time. Drift mines are banned under international law if they do not automatically deactivate one hour after being released.
- Anchor mines: They are simple weapons that can be produced and used inexpensively even by technologically backward countries. Anchor mines consist of a mine cart or anchor that sinks to the seabed and the mine vessel, which is attached to the mine cart with a wire rope, the so-called anchor rope, and floats a few meters below the sea surface due to its buoyancy. If a ship touches the detonator, the mine detonates. This design makes it possible to specifically block certain shipping routes. A minefield can have a significant impact, particularly in narrow sea areas – such as the Strait of Hormuz.
At greater depths, anchor mines are also used against submarines.
- Basic mines: They are technically more demanding and more difficult to clear than anchor mines. They lie on the seabed, often in shallower waters, and do not respond to direct contact, but rather to various signals from a passing ship – such as magnetic fields from large steel hulls, noises from ship’s propellers or changes in pressure in the water.
- Torpedo mines: These new mines initially lie on the seabed like ground mines. When the sensors detect a target, the mine launches a torpedo-like explosive device that searches for its target.
Why are sea mines used?
Thanks to their relatively simple construction and low cost, sea mines allow even states that do not have highly equipped naval forces to block entire maritime areas. Mines are therefore particularly attractive for such states, including Iran.
Even a small number of mines can bring maritime traffic to a standstill. In modern shipping markets The economic impact of mines often exceeds their military impact. Insurance premiums are skyrocketing, ports are suspending operations and shipping companies are refusing to send ships through potentially mined waters until the Navy clears the area.
Iran also laid mines in the Persian Gulf during the so-called Tanker War in the 1980s, which was part of the Iran-Iraq War. One of these damaged the frigate USS Samuel B. Roberts (FFG‑58), which was escorting a Kuwaiti oil tanker, in 1988.
How long do sea mines remain dangerous?
After Estimates from the German Bundeswehr There are still around 1.6 million tons of conventional ammunition from the two world wars in German waters in the North and Baltic Seas – mainly sea mines and aerial bombs that have been rotting under water for decades. There are estimated to be up to 100,000 sea mines in the Baltic Sea alone. Some of them are still explosive and not only pose a danger to shipping and the construction of offshore wind farms, but also release toxins into the sea, such as phosphorus. These toxins accumulate through the food chain and ultimately end up on our plates.
If sea mines become loose from their moorings and drift through currents and storms, they can become an uncontrolled danger. For example, in spring 2022 there were several Sea mines floating off the Turkish coast discovered. Shipping traffic on the Bosphorus was partially suspended. Observers suspected a connection with the Ukraine war. There are countless sea mines in the Black Sea.
How are sea mines cleared?
As easy as it is to deploy sea mines, it is just as difficult to remove them again – this is one of the most demanding tasks of modern naval forces. Be differentiated mine clearing and mine hunting. The warships used for this purpose are summarized under the general term “mine countermeasures vehicles”.
Mine clearance
When clearing mines, mines in a specific search area are rendered harmless using technical means. The methods differ depending on the type of mine:
- Anchor mines are cleared using so-called clearing harnesses, which are pulled through the water by minesweepers and cut the mines’ anchor lines. The mines then float to the surface where they are destroyed.
- Ground mines are detonated using simulated magnetic fields or sounds. However, pressure fields cannot be simulated; Mines with pressure detonators can only be cleared by specially protected ships that sail over the mines and detonate them.
Turkish minesweeping ship with an unmanned underwater vehicle for mine hunting.Image: www.imago-images.de
Mine hunting
Mine hunting uses specialized mine clearing boats and remotely operated underwater vehicles to locate individual mines using high-resolution sonar devices. They can then either be defused or specifically blown up. In some cases, mine divers also have to be deployed to identify mines and destroy them.
But even with modern technology, mine hunting remains time-consuming; it can take hours to find and defuse a single mine. Here too the economic effect is significant: Eliminating a mine costs many times the cost of creating and laying it.
Dolphins were also used to detect mines and deliver destruction charges to the mines found. However, modern mine hunting drones are more reliable with less effort.Image: AP
In the Persian Gulf, it is likely that units from the US Navy, the Royal Navy and other allies of the Western powers will be tasked with clearing mines. (dhr)