In January 2026, the U.S. Navy loaded four wooden-hulled minesweepers onto a heavy-lift cargo ship in Bahrain and sent them to Philadelphia for disposal. The USS Devastator, USS Sentry, USS Dextrous, and USS Gladiator had guarded the Persian Gulf's sea lanes for over 30 years each. Their replacements — three Independence-class Littoral Combat Ships carrying next-generation unmanned mine-hunting packages — had just arrived in theater. The transition was declared complete. Nine weeks later, Iran reportedly began laying mines in the Strait of Hormuz. The United States found itself staring down a potential mine crisis in one of the world's most vital shipping lanes, armed with a system that had never been used in combat and, according to the Navy's own internal assessments, suffered from unreliable unmanned vehicles, sonar that failed to record data during exercises, and equipment that went rogue off the coast of San Diego.
The Decision: Retiring the Avengers
The Avenger-class mine countermeasures ships entered U.S. Navy service beginning in the 1980s. The Navy manufactured 14 of them in total, according to Navy surface warfare command records. Their wooden hulls — coated in fiberglass — were purpose-built: wood and fiberglass produce minimal magnetic signatures, reducing the risk that magnetically-triggered mines would detonate as they passed overhead. The Avengers deployed in the Persian Gulf during the Gulf War in 1990-1991, destroying over 1,000 mines off Kuwait, according to Navy Times.
The four ships stationed at Naval Support Activity Bahrain — USS Devastator (MCM-6), USS Sentry (MCM-3), USS Dextrous (MCM-13), and USS Gladiator (MCM-11) — were formally decommissioned on September 25, 2025, according to USNI News and the U.S. Naval Institute's Proceedings journal. In January 2026, they were loaded onto the M/V Seaway Hawk and transported back to the United States, according to Wikipedia's Avenger-class entry citing naval records. Each had served more than 30 years.
The stated reason for retirement was replacement, not redundancy. Independence-class Littoral Combat Ships equipped with a new Mine Countermeasures (MCM) Mission Package had been arriving in the Fifth Fleet over the preceding year. The USS Canberra arrived in the Middle East on May 22, 2025, according to Navy Times. The USS Santa Barbara and USS Tulsa followed, with all three counted as active by September 25, 2025. A fourth LCS with the package was reportedly en route, per USNI News.
The Navy's official position, stated to Military Times on condition of anonymity, was that the new system represented an upgrade: "The LCS MCM mission package is a sophisticated suite of manned and unmanned systems designed to locate, identify, and neutralize sea mines, at a safer distance from minefields than the Avenger-class MCMs."
The Threat: Iran's Mine Arsenal and Doctrine
Naval mine warfare is not a peripheral concern when it comes to Iran — it is a central pillar of the Islamic Revolutionary Guard Corps Navy's military doctrine, according to a 2017 Office of Naval Intelligence report. Iran views mines as an asymmetric tool capable of disrupting a technologically superior adversary's naval operations at minimal cost.
Iran is estimated to possess roughly 6,000 mines, according to a Congressional Research Service report cited by Military Times on March 16, 2026. The stockpile reportedly spans multiple types: limpet mines, which are attached to ship hulls manually by divers; moored mines, tethered below the surface; bottom mines that rest on the seabed; and drifting contact mines. This range of mine types complicates clearance — different mine designs require different countermeasures.
On March 10-11, 2026, Reuters reported that Iran had deployed approximately a dozen mines in the Strait of Hormuz, citing two sources familiar with the matter. CNN separately reported on March 10 that "a few dozen" mines had been laid in recent days, citing intelligence sources. Defense Secretary Pete Hegseth said on March 16 there was "no clear evidence" of mines in the strait — a statement that Reuters noted came after earlier reporting of the deployments. According to CNN's intelligence sources, Iran still retained "80% to 90% of its small boats and miners" as of mid-March despite U.S. strikes on 16 Iranian minelaying vessels on March 11, per CENTCOM announcements.
U.S. Admiral Brad Cooper, head of CENTCOM, announced on March 16 that U.S. forces had destroyed storage bunkers for naval mines during a strike on Kharg Island on March 14. But the destruction of storage infrastructure does not eliminate the mines already deployed or the capacity to deploy more from surviving platforms.
The Gap: Three Untested Ships Against a Known Doctrine
The Washington Institute for Near East Policy estimated years before the current conflict that clearing the Strait of Hormuz of mines could require "up to 16 MCM vessels," according to Hunterbrook Media's reporting. As of the conflict's outbreak, the U.S. Navy had seven total mine countermeasures vessels — and three were positioned near the Persian Gulf. Two of the three LCS ships equipped for mine clearance — USS Santa Barbara and USS Tulsa — were in Singapore as of mid-March, according to Navy Times. The third, USS Canberra, equipped with mine-countermeasures packages, was also in Asia per Hunterbrook's reporting.
Emma Salisbury, a senior fellow at the Foreign Policy Research Institute, told NPR she was "honestly completely baffled" as to why the Navy wouldn't have mine-clearing resources near the Middle East at the start of the conflict. "Having a mine countermeasures capability that is not in theater is not particularly helpful," she told NPR on April 1, 2026.
Maritime security expert Scott C. Truver told NPR that funding for mine warfare accounts for "less than 1% of the Navy's total budget." He noted that mine warfare has received "minimal attention and funding from the Navy, overshadowed by higher-profile weapons systems," and that some people call it a "stepchild of the U.S. Navy."
The scale of the asymmetry is stark: since World War II, sea mines have sunk or crippled 15 U.S. Navy vessels — more than from all other weapons combined, according to a 2015 Breaking Defense analysis cited by NPR. Three U.S. warships were damaged by sea mines in the Persian Gulf since 1988, injuring dozens of sailors. The threat is not theoretical.
The Replacement's Problems: Internal Navy Assessments
The reliability of the LCS MCM Mission Package is directly contested by the Navy's own internal documentation. Hunterbrook Media obtained a copy of a U.S. Navy presentation titled "LCS MCM Mission Package Lessons Learned," delivered nine months before Iran reportedly began mining Hormuz — approximately June 2025 — by a Navy director in charge of the mine countermeasures technical division to an audience of international naval observers in the United Kingdom.
Key findings from that presentation, as reported by Hunterbrook:
Unmanned surface vehicles (USVs) — the core detection platform — require over four hours of "pre-mission maintenance" and "1.5 hours of GPS/sonar calibration once launched." Multiple hunt missions were conducted where the sonar simply failed to record data, and crews did not know until post-mission analysis. This failure mode is described as "especially damaging during reacquire-and-identify missions" — the exact kind of work needed to clear a minefield.
During a pre-deployment exercise with the USS Tulsa off the coast of San Diego, a runaway MCM USV went to the edge of Mexico's territorial waters and could not be recovered by the mothership LCS. Hunterbrook quoted the briefing's characterization of the training area: "Literally, the practice minefield I use is 1 mile north of the US-Mexico [border]."
The LCS MCM Mission Package reached initial operational capability in September 2022, per Defense News. It reportedly did not deploy on an actual ship until USS Canberra and USS Santa Barbara sailed in February 2025. USS Tulsa followed in May 2025. The entire operational history of the system, from first deployment to the current crisis, is measured in months.
The USNI Proceedings article published in April 2026 summarized the structural gap directly: "The current conflict has exposed the yawning gap in U.S. MCM capability. The United States has three MCM-countermeasures ships, no dedicated MCM helicopters, and a limited number of LCS MCM modules, all of which face operational challenges."
A 2022 Government Accountability Office (GAO) report cited by NPR noted "several significant challenges" with the LCS, "including the ship's ability to defend itself if attacked and failure rates of mission-essential equipment." The modular concept — the LCS's original selling point — has been "quietly abandoned," according to Hunterbrook and naval reporting outlet Naval News.
The NATO Question and Allied Capability
Defense Secretary Pete Hegseth on April 1, 2026 told allied nations they needed to do more to help reopen Hormuz, including what NPR described as a "veiled reference to Britain in particular." European nations have largely declined to contribute warships to the Iran war effort, according to Politico EU. But USNI Proceedings noted that allied mine countermeasures forces may be more capable than the U.S.'s own: "When it comes to mine clearance, the U.S." — the Proceedings piece was cut off by the paywall in available excerpts, but its premise is that NATO allies retain dedicated MCM vessels that the U.S. has largely retired.
Bryan Clark, a senior fellow at the Hudson Institute, told NPR that the new LCS system, in theory, does not require close proximity to minefields: the ships "stand clear of the minefields and then allow their unmanned systems and helicopters to do the locating and mine neutralization." The problem, as the Navy's own lessons-learned briefing documented, is that the unmanned systems have not demonstrated that capability reliably in exercises — let alone in the warm, turbulent, cluttered waters of the Persian Gulf under wartime conditions.
Why It Matters
The Strait of Hormuz carries approximately one-fifth of the world's oil supply through a navigable channel roughly two miles wide in each direction. The International Energy Agency characterized the current supply disruption as the "largest in the history of the global oil market," according to prior Ranked reporting. The question of whether the strait can be physically reopened — not just diplomatically negotiated open — now depends in significant part on the Navy's ability to locate and neutralize whatever mines Iran has deployed or may still deploy.
The timeline of decisions that led to the current situation is traceable and documented. The Avenger-class ships were decommissioned in September 2025 and physically removed from the theater in January 2026. Iran reportedly began mine operations in March 2026. The replacement system had been deployed operationally for less than a year and had never been used in combat. The mine warfare budget had for years accounted for less than 1% of total Navy spending.
Whether those decisions constitute a catastrophic planning failure or a reasonable modernization gamble gone wrong under unforeseen circumstances is a judgment call. What is not a judgment call: the Avengers are gone, Iran has an estimated 6,000 mines, and the three ships now responsible for clearing Hormuz have sonar that went silent in pre-deployment exercises and unmanned vehicles that, at least once, could not be recalled from the edge of Mexican waters.
The Navy says the system is ready. The Navy's own briefing slides say otherwise. The strait will settle the argument.