Iran’s use of small, high-speed craft to capture two container ships close to the Strait of Hormuz has exposed limits in the view that its naval power has been largely neutralised and presents fresh difficulties for reopening one of the world’s most important energy export routes.
U.S. President Donald Trump acknowledged that while Iran’s conventional navy had been largely destroyed, its “fast-attack ships” remained and had not previously been treated as a major threat. He said any such vessels approaching a U.S. blockade established outside the strait would be "immediately ELIMINATED" using the "same system of kill" applied in operations in the Caribbean and Pacific where U.S. air strikes have targeted suspected drug vessels and resulted in at least 110 deaths.
Those drug-interdiction operations involved boats that were neither attacking large, unarmed commercial shipping nor carrying the heavier armament attributed to members of Iran’s Revolutionary Guards, who are reported to mount heavy machineguns, rocket launchers and, in some instances, anti-ship missiles on their craft.
Greek maritime security firm Diaplous described the fast-boat seizures as part of a “layered system of threats” that also includes shore-based missiles, drones, mines and electronic interference - a combination intended to inject uncertainty into maritime decision-making and slow response times.
Maritime security experts estimate Iran maintained hundreds, if not thousands, of these small, fast boats before the current conflict, often concealing them in coastal tunnels, naval bases or among ordinary civilian vessels. Corey Ranslem, chief executive of Dryad Global, said that some 100 or more of those vessels may have been destroyed since the Iran war began on February 28.
Change in tactics
Prior to this week’s vessel seizures, Iran had leaned heavily on missile and drone strikes to target shipping in and around the strait - a passage that typically carries about 20% of the world’s daily oil and liquefied natural gas supply. Those missile and drone attacks had subsided following an April 8 ceasefire.
The recent captures occurred after the United States implemented a maritime blockade of Iranian trade and began intercepting tankers and other ships linked to Iran.
Daniel Mueller, a senior analyst at British maritime security company Ambrey, said civilian commercial ships are not equipped to stop armed forces from boarding and seizing vessels. Mueller noted that a typical seizure operation employs roughly a dozen fast boats.
Officials within Iran have framed the fast-boat fleet as central to its naval approach. A senior Iranian security official, speaking on condition of anonymity, told Reuters these craft form the “backbone” of their naval strategy, able to deploy quickly in what the official described as an asymmetrical approach to confronting adversaries. "Because of their very high speeds, these boats can successfully carry out hit-and-run attacks without being detected," the official said.
Operational limits of fast boats
Even as they have proved effective in certain circumstances, small, fast boats have limitations. Ambrey’s Mueller said including this week’s incidents, Iran has used such craft at least seven times since 2019. Seasonal weather off Iran’s coast - notably high winds and swells during the summer months - make these operations difficult; an Iranian shipping source familiar with the local waters told Reuters that when seas are very rough, "they (armed forces onboard) cannot shoot."
Analysts also stress these craft are poorly suited to confront a properly equipped warship in a conventional engagement. Jeremy Binnie, a Middle East specialist at defence intelligence company Janes, cautioned that fast boats attempting a direct assault on a warship would likely sustain "very heavy casualties." He added that even coordinated, multi-directional attacks to overwhelm a ship’s defences would leave the boats vulnerable to air support called in during such an engagement.
Binnie also observed that while guided missile strikes could theoretically destroy small fast boats relatively easily on paper, the presence of shoulder-fired missile launchers would present a hazard to low-flying aircraft engaged in countering the threat.
He concluded that eliminating the small-boat threat will be more difficult than the task of destroying Iran’s larger naval ships, which were larger, easier to find and track, and carried only a limited ability to defend against air attack.
Industry implications
For the commercial shipping sector the practical consequences are immediate: heightened disruption to movements and increased insurance premiums. The combination of seaborne interdictions, asymmetric tactics and the unpredictable mix of weapons and platforms operating in the area complicates voyage planning and risk assessment for shipowners and charterers.
Former Royal Navy vice admiral and consultancy director Duncan Potts said Iran shifted historically toward asymmetric tactics after its conventional navy was effectively neutralised in earlier conflicts, a pattern he said mirrors the present conflict. Potts noted the danger of underestimating a force that has adapted to operate outside conventional naval paradigms, saying in effect that previous statements of having destroyed Iran’s navy overlook the opponent’s turn to asymmetric methods and their continued refinement of those methods. "When the U.S. Navy and the president say, 'We've destroyed the navy, we've sunk a frigate off Sri Lanka' - you've done that before, but you've forgotten that your opposition here went asymmetric. And they've perfected it," he said.
The persistence and adaptability of Iran’s fast-boat capability therefore pose both tactical and commercial headaches: while the craft are limited in certain high-seas and direct combat scenarios, their speed, concealability and integration into a larger threat layering mean they remain a potent tool for exerting control or creating friction in and around the Strait of Hormuz.
As the blockade and interdiction activity continues, the balance between removing direct threats and managing the broader asymmetric risk will be central to whether and how maritime traffic through the strait can be restored to normal levels.