Maritime mines pose a serious risk in strategic waterways such as the Strait of Hormuz and the South China Sea. Beyond the direct danger to warships, even the suspicion that an area may be mined can halt or slow commercial traffic along routes vital to global trade and oil shipments.
Bryan Clark, director of the Hudson Institute’s Center for Defense Concepts and Technology, said mines are relatively easy to obtain, build and deploy. They do not need to be sophisticated or precisely guided: placing them near a shipping channel can be enough to create uncertainty and disrupt traffic.
Some mines detect acoustic or magnetic signatures, while others can be set to detonate after a certain number of vessels pass. But mines can be effective without such features. Once there are indications that mines may be present, shipping companies are likely to suspend traffic until the threat is assessed—or accept higher insurance costs and the possibility of losing a vessel.
A blockade tool within reach of smaller countries
The low barrier to entry makes mines an attractive option for countries seeking to restrict access through a strait or another narrow passage. Clark pointed to Finland’s plans to mine the Gulf of Finland as an important part of its defense planning in the event of conflict with Russia.
Iran, meanwhile, has long viewed mines as one of its principal offensive weapons. The Strait of Hormuz is particularly vulnerable because it is narrow and crucial to global commerce. Clark said Iran even has rockets capable of deploying mines from a distance.
How a mine threat is assessed
Maritime operators cannot afford to dismiss a possible mine threat. The first priority is to identify and verify a safe, mine-free channel. Once a clear route has been confirmed, ships can be guided through it even if a threat remains elsewhere.
If traffic needs to increase or vessels must travel in both directions, a larger area has to be surveyed and the safe passage widened. In the early stages of the conflict described by Clark, robotic mine-hunting systems were used to verify a channel along the Omani coast.
Robots keep crews out of danger
Mine hunting once required sending crewed vessels directly into hazardous areas. Such ships were generally built from wood or fiberglass to reduce their magnetic signature and used sonar and towed equipment to detect or neutralize mines.
Today, a significant part of the work can be carried out by robotic vehicles. Equipped with active sonar, they survey the seabed and water column along planned routes. After a mission, their data is analyzed with software that helps identify objects requiring further investigation.
Additional robots can then inspect suspicious objects to determine whether they are mines, debris or other harmless items. If an object needs to be neutralized, helicopters or small boats can deploy vehicles guided by fiber-optic cables. An operator steers them to the target, where their charge can destroy the mine or puncture it so that it sinks.
These systems keep personnel outside the minefield and make it easier to scale up operations. Instead of buying and crewing more minesweepers, a navy can acquire a larger number of robots, store them and deploy them when needed.
The next step: real-time processing and communications
One limitation of current methods is that they rely on multiple passes. Vehicles search for mines, return to offload their data, and are followed by other systems sent to investigate suspicious objects and neutralize confirmed threats.
Clark said onboard data processing and faster communications could reduce those delays. An underwater vehicle could report the results of a search route and transmit the locations of suspicious objects immediately. Commanders could then decide in near real time whether to send another robot to investigate or move directly to neutralization.
