U.S. Navy Retires Last Avenger-Class Minehunters, Faces Challenges with LCS Transition

The U.S. Navy has officially retired its last Avenger-class mine countermeasures (MCM) ships in Bahrain, marking the end of more than three decades of service in the vital mission of clearing sea mines under Task Force 55. These ships, first commissioned in the 1980s, played a critical role in ensuring freedom of navigation in some of the world’s most contested waters, especially the Persian Gulf, where the threat of sea mines remains high.

The final ship to be decommissioned, USS Devastator (MCM 6), closes a long chapter of dedicated service. The Navy has now shifted to using Independence-class Littoral Combat Ships (LCS) fitted with specialized mine countermeasure packages as replacements. While this transition is presented as a modernization effort, the Navy is facing serious operational challenges with the new systems.

From Legacy Ships to High-Tech Modules

The Avenger-class ships were wooden-hulled vessels designed specifically for minehunting and minesweeping operations. They relied on sonar, remotely operated vehicles, and explosive ordnance disposal (EOD) divers to identify and neutralize threats. Their proven design and durability allowed them to remain in service far longer than expected.

By contrast, the Independence-class LCS is a multi-mission platform. Its MCM role is carried out using advanced technologies such as:

• MH-60S Seahawk helicopters equipped with the AN/AES-1 Airborne Laser Mine Detection System (ALMDS) for shallow-water mine detection.

• The AN/ASQ-235 Airborne Mine Neutralization System (AMNS), which allows safer mine destruction than traditional diver methods.

• Common Unmanned Surface Vessels (CUSVs), also called Fleet-class USVs, developed by Textron Systems. These can deploy either the AN/AQS-20C sonar for mine detection or the Unmanned Influence Sweep System (UISS) for acoustic and magnetic mine sweeping.

Problems with the New System

While these systems represent a leap in technology, they are proving difficult to operate reliably in real-world conditions. One test in Bahrain involving the USS Tulsa (LCS 16) resulted in a runaway unmanned surface vessel after a tow bracket failed, forcing another ship to recover it.

The sensors also face major shortcomings. The CUSV sonar lacks the resolution needed to reliably identify threats, while the laser systems on helicopters cannot operate effectively in murky or turbid waters. This creates gaps in minehunting ability compared to the simpler, proven methods used on the Avenger-class.

Another challenge is the extensive preparation time required before each mission. On average, crews must spend six hours on pre-mission checks, calibration, and maintenance before operations can begin—an impractical timeline in combat situations.

High Risk of Failure Points

The LCS MCM system also suffers from single points of failure. For example:

• The mission bay lift is needed to move minehunting gear to the flight deck. If it fails, helicopters cannot be equipped with their MCM sensors.

• If the CUSV tow hook breaks, the unmanned vessel becomes inoperable.

• If the Twin Boom Extensible Frame malfunctions, no USVs can be launched, effectively ending MCM operations.

These vulnerabilities mean that a single breakdown could render the entire ship’s mine countermeasure capability useless.

Current Deployment

Three Independence-class ships—USS Canberra (LCS 30), USS Santa Barbara (LCS 32), and USS Tulsa (LCS 16)—are now forward-deployed in Bahrain, taking over from the retired Avenger-class. These ships form the backbone of the Navy’s new mine warfare strategy.

However, naval officials and experts have expressed concerns that the new MCM mission modules are not yet fully capable of replacing the reliability of the Avenger-class. The Navy is working to improve sensor fidelity, reduce failure points, and increase mission readiness, but progress has been slow.

Why This Matters

Mine warfare remains a critical naval mission. Sea mines are inexpensive, easy to deploy, and capable of crippling even the most advanced warships. With rising tensions in the Middle East and South China Sea, the Navy’s ability to clear sea lanes quickly is more important than ever.

The retirement of the Avenger-class ends a proven era, while the transition to LCS mine countermeasures is a step toward modernization that still faces serious hurdles. Until those challenges are overcome, the Navy’s mine warfare capability may remain at risk during high-stakes operations.