Iran Maintains Fleet of Fast Boats in Strait of Hormuz

Hundreds of fast-attack boats operated by Iran lie hidden in coves, caves and tunnels along the country's southern coast. At a signal, the vessels swarm into the Strait of Hormuz, where they harass ships and demonstrate the ability to disrupt passage through the waterway.

Many of the boats are basic speedboats with light armament while others carry short-range missiles. The boats form part of the Islamic Revolutionary Guard Corps navy and have faced the U.S. Navy while contributing to reduced traffic through the strait.

The vessels lack the firepower to seriously damage U.S. warships or modern tankers. Coupled with missiles and drones, however, they have created a threat level that has deterred many merchant ships. "Anytime there’s something flying at a vessel, whether it’s a navy vessel or a merchant vessel, it’s a real and present risk to the sailors or mariners on board," said Joshua Tallis of the Center for Naval Analyses.

The U.S. military has deployed a large naval presence to the region. Officials said attack helicopters sank six fast boats on Monday during an operation called Project Freedom that aimed to allow merchant ships to transit the strait. The U.S. military reported that only six boats approached during that incident compared with the 20 to 40 typically seen in such groups.

A U.S. military commander stated that the lower number of boats dispatched provided evidence that the capability had been degraded. Iran stated that the U.S. struck civilian boats. The U.S. military has said it took down additional small boats in skirmishes on following days.

The operation was paused to allow room for negotiations with Tehran. Iran continues to control the flow of merchant vessels through the strait while the U.S. maintains a blockade on Iranian ports.

The fast boats were first developed during the Iran-Iraq war in the 1980s. They operate in packs to intimidate slower vessels, target crews, damage cargoes, assist in ship seizures and lay mines. The fleet uses inexpensive domestically produced boats that can be replaced easily along with more advanced models such as the Seraj-1, which is based on a British racing boat design.

The conventional Iranian navy consists of older vessels including corvettes acquired more than 50 years ago and aging submarines, some of which are inoperable. One analyst described destruction of the conventional navy as true but irrelevant because that force had functioned mainly as a parade unit.

Iran relies instead on the IRGC navy, cruise missiles, drones and other asymmetric assets. Estimates place the IRGC fleet at between 500 and 1,000 operational armed speedboats of varying capabilities. The force also controls more than 1,000 drone boats and coastal missile batteries.

The IRGC has held sole responsibility for defense of the Gulf and the Strait of Hormuz since 2007.

If the boats remain operational and Iran proceeds with plans to charge vessels passing the strait after the current conflict, the fast-attack craft would play a central role in policing the waterway. The U.S. Navy possesses the ability to counter the threat but it requires substantially more resources to protect shipping than it takes to raise insurance costs and discourage transit.

"They don’t have to hit every ship going through Hormuz, they just have to hit enough to keep the insurance market on edge," one analyst said. " The U.S. Navy’s Fifth Fleet, based in Bahrain, has observed these boats harassing American warships during past periods of tension.

The vessels are regarded as more of a nuisance than a lethal threat when operating in open water but could be equipped with explosive charges. Analysts note that sustained U.S. naval presence in the region would be required to keep the boats suppressed over time.