On Friday, German Chancellor Friedrich Merz said his country was ready to provide mine clearance and maritime reconnaissance supplies to help secure the Strait of Hormuz.
“We can provide mine-clearance vessels – we’re good at that,” Merz said, adding that such an intervention would need a “solid legal basis”. His announcement followed consultations with fellow European leaders on a possible multinational mission to secure the strait after the war.
The same day, Iran’s top diplomat Abbas Araghchi declared the vital waterway “fully open” for the duration of the Israel-Lebanon ceasefire, and US President Donald Trump also said it was “ready for full passage.” The next day, Iran reversed its decision and closed the strait again.
Either way, maritime traffic may still be in danger, given that Iranian officials have previously indicated that there may be underwater mines in the strait. Experts aren’t so sure.
“We’re not even sure there are mines there [in the Strait of Hormuz],” said Johannes Peters, an expert on undersea warfare at the Institute for Security Policy at Kiel University. ”But the inherent danger is substantial [to deter passage]. “Right now, no one can actually go to the war zone and investigate.”
How do sea mines work?
Naval mines are relatively inexpensive underwater explosive devices designed to detonate when triggered by nearby ships. There are three main types depending on their location:
- floating mines that float on or near the surface of water
- Swamp mines that float beneath the surface of the water and are attached to the seabed
- Low-lying mines that rest on the seabed.
During the Second World War, switch horn mooring mines, which detonated on contact with a ship, were the standard British naval mine – copied from German mines developed in the First World War. “Modern mines have very little to do with them,” Peters told DW.
The firing mechanism on newer devices no longer requires actual contact, rather it can be triggered by certain magnetic effects, underwater sound waves or reduced pressure under water caused by passing ships.
To program such a mine for a particular class of ship, “submarines can help determine the acoustic profile of a hostile ship,” Peters explained. “These hostile ships will trigger the mines by their acoustic signals, while friendly ships can pass through the mine area without any disturbance.”
Searching for possible explosives is going to take time
The process of clearing mines, including searching for the mine and clearing the mine, can be time-consuming. To hunt a mine, suspicious objects must first be located, then experts must determine whether it poses a threat.
If this happens, there are several ways to deal with it: experts can retrieve the mine, disarm it or cause a controlled underwater detonation. Peters compared it to an “underwater ordnance clearing service”.
But recent developments offer new opportunities to clear mines without risking lives. “When possible, we use drones to search for objects, then identify and destroy them,” Ukrainian soldier Mykola told DW earlier this year. She is part of a Ukrainian task force clearing naval mines in the Black Sea, which was laid by Russia as part of its war of aggression.
German Navy: Mine hunting with drones
Germany’s navy has also started using drones to hunt for sea mines. “We mainly use autonomous systems to search the seabed,” Andreas, a frigate captain of the German Navy’s 3rd Minesweeping Squadron, told DW. For security reasons, we are allowed to publish only his first name.
“In the past, boats equipped with sonar systems had to pass directly through areas where mines were suspected to be detected,” Andreas added. “Autonomous systems mean those 40 lives no longer have to be put at direct risk.”
They also greatly reduce the need for human personnel. The drones independently transmit footage from the sea floor back to their station for evaluation. But it’s still up to humans to separate harmless junk from deadly sea mines by watching the footage, and decide how to deal with the explosive once they find it.
Using drones to search the seafloor has made the Navy more efficient overall, Andreas said, but it could still take decades or longer to clear the seabed of mines after a war. Artyom, another Ukrainian mine sweeper in the Black Sea, supported this with his own experiences.
“We are still finding mines from World War II and even some from World War I,” he said. “This shows how many years of work we still have to do.”
Strait of Hormuz: Too difficult to deploy drones?
The battery capacity of drones used by Germany’s navy still limits how long they can be deployed over open water. For now, they should be released fairly close to the area they are to explore.
“You always have to be close,” Andreas explained. “This will be difficult in a sensitive area like Iran’s Strait of Hormuz.”[ian weapons have] A long distance, and we need to protect the people who work for us.”
Many companies are already working on developing drones that can operate for long periods. One of them is EuroAtlas from Bremen, northern Germany. The company says its underwater Greyshark drone can currently last up to 6 hours at 10 knots (18.5 kph; 11.5 mph) or three times as long at 4 knots.
EuroAtlas has announced that the autonomous, battery-powered version will go into production in September 2026. Series production of later models equipped with fuel cell systems allowing week-long deployments is expected by the end of the year.
Greyshark drones may be deployed soon
Markus Beer is Chief Sales Officer for so-called autonomous underwater vehicles (AUVs) at EuroAtlas. He told DW how Greyshark drones could be useful in the current crisis off the coast of Iran.
“Ships in the Strait of Hormuz are at risk of ground fire,” he said. “This also includes minesweepers. But underwater [drone] Reconnaissance may still be possible without risk and without escalating the situation.”
He said the Greyshark drones offered the advantage of wide range, allowing them to be launched at a safe distance. “Small drones currently used to hunt mines can only operate for a few hours,” the sales executive said. “Greyshark drones can travel much further, while also being able to take high-resolution images and independently identify objects on the ocean floor,” he said.
Last September, EuroAtlas demonstrated the capabilities of its Greyshark underwater drone at a world-leading event for the testing of unmanned marine systems, robotic experimentation and prototyping using Marine Unmanned Systems (REPMUS), held off the coast of Portugal.
This article was originally written in German.