Why the Iranian Navy keeps losing warships in accidents, after its Sahand frigate capsized and sank

• An Iranian Navy frigate sank two days after capsizing in port.
• The latest incident suggests a lack of training and a design flaw with the Iran-built ship.

In another embarrassing incident for Iran's Navy, the frigate Sahand capsized on Sunday before completely sinking on Tuesday in the shallow waters of the port of Bandar Abbas in southern Iran. It was the third navy ship Iran has lost in an accident since 2018.

According to state-controlled Iranian media, the Sahand initially "lost its balance due to water leakage into the tanks" on Sunday and rolled onto its side, with only part of the hull and sonar dome appearing above water, resulting in at least one fatality and an undisclosed number of injured, but "quickly returned to a balanced state." On Tuesday, however, local media reported the vessel had completely sunk, claiming a rope that was holding it broke.

The string of accidents suggests a lack of baseline training and supervision at a time its conventional navy is losing traction to its paramilitary competitor, with one expert cautioning that sabotage should not be ruled out. It also may be the Iranian-made frigate has a design flaw that makes it too tippy.

Bryan Clark, a senior fellow at the Hudson Institute and expert on naval operations, believes the incident was "largely the result of poor maintenance and inadequate training."

"The updated design probably didn't help because it raised the center of gravity, which will reduce its stability," Clark told Business Insider.

Iran launched the 315-feet-long, 1,300-ton vessel, named after another Iranian warship sunk by US forces during a 1988 naval clash, in late 2018. At the time, Iranian media boasted it could travel for approximately five months without refueling. It also had a helicopter pad, sophisticated radar, surface-to-surface and surface-to-air missiles.

Steven Horrell, a former naval intelligence officer and senior fellow with the Transatlantic Defense and Security Program at the Center for European Policy Analysis, suspects "maintenance and training played a part" in the accident.

"If the cause was a rapid influx of water into the ballast tanks or other compartments, that says that some material condition was lax, whether the setting of valves within the transfer systems or what hatches and doors and scuttles are supposed to be secured or open," Horrell told BI. An intake of water is usually supervised because too much water piped into one ballast tank or one side of the ship can cause the hull to heel or even topple.

"And then it looks like whatever crew was aboard during that pier-side maintenance was not postured to respond."

While the Sahand's hull is "certainly salvageable," the CEPA fellow anticipates "a long process" for returning it to service.

"Electronics and seawater don't mix, and for that matter mechanical parts — the whole engineering plant and propulsion train — are subject to water damage and corrosion," Horrell said. "They will be replacing systems from stem to stern."

Iran's Navy lost two other warships to accidents in recent years.

In June 2021, it lost the 680-feet-long Kharg support ship, the Iranian Navy's largest by tonnage, in a fire, injuring 33. In January 2018, the 315-feet-long Damavand frigate, described as the navy's "most important warship on the Caspian Sea," sank after it hit the breakwater at Bandar-e Anzali port during high seas, killing two crew.

The Kharg incident is distinct since a fire destroyed that ship, and also because the vessel had been built by the United Kingdom.

Clark noted the Damavand, a ship in the same indigenous class as the Sahand, "ran aground and could have capsized because of instability created by the updated design."

"This calls into question the design itself, although proper training and maintenance would likely be able to mitigate the design shortfalls," Clark said. "At the very least, I cannot imagine any other countries being interested in Moudge-class frigates."

Horrell also noted that this class of frigates is based on the older Alvand-class frigates built by the UK for pre-revolutionary Iran in the late 1960s and early 1970s.

"They are indigenously designed, but based off the import Alvand-class," Horrell said. "If you put more superstructure on a similar hull, you might be creating center of gravity problems, which would contribute to the rapid rollover Sahand experienced."

In other words, more high weight on a ship increases the risk that if the ship heels it can act as a lever that rolls the ship over, a catastrophe that renders the ship useless and endangers its crew.

Horrell also stressed that the three incidents were all different.

"A fire like on Kharg is a critical concern for every Navy; Damavand ran aground in reportedly terrible weather conditions in the Caspian Sea," Horrell said. "But one probable common thread is damage control. Every sailor on board should have some basic damage control training or firefighting training; these are all-hands operations."

Consequently, he believes "better damage control" and "training, professionalism, personnel" may have saved some of these ships and prevented injuries and loss of life. Furthermore, it could also "be a small reflection of government prioritization" of the Islamic Revolutionary Guard Corps Navy over Iran's Navy.

"Budgets are not just ships and shipbuilding," Horrell said. "Budgets are training, maintenance, and personnel."

Iran has two navies: its Navy, known as the Islamic Republic of Iran Navy, and the naval arm of the powerful Islamic Revolutionary Guard Corps paramilitary organization. For decades, the IRGC Navy patrolled the Persian Gulf north of the Strait of Hormuz using speedboats and fast patrol crafts, while the IRIN, with its larger warships, generally deployed in the seas beyond the Gulf. But in recent years, the IRGCN has built larger craft, including oceangoing vessels.

"If you look at the numerous incidents of unsafe and unprofessional interactions with the US Navy or other navies, those are the IRGCN," Horrell said.

Since the 1979 revolution, the ruling authorities in Iran favored the IRGC over the regular military.

"The IRGCN is certainly favored in the Iranian government, partly because it is seen as more loyal to the Supreme Leader and partly because it operates businesses that provide cash to government officials," Hudson's Clark said.

"The design flaws that seem to be a contributor to the problems experienced by these ships are not directly attributable to the government's budget priorities," Clark added. "But the lack of training and maintenance that directly led to these accidents can probably be traced to the IRIN having lower precedence in budget competitions to the IRGCN."

Farzin Nadimi, a defense and security analyst and senior fellow of the Washington Institute for Near East Policy, noted that "on the surface," the regime tries to portray the IRGCN and IRIN as cooperating, while the reality is much more sinister.

"In effect, the IRGC is eating into the IRIN's turf and budget with all these new 'oceangoing' vessels they are commissioning, while they were supposed to limit their area of responsibility to the littorals," Nadimi told BI.

"Therefore, sabotage by the IRGC in order to undermine and weaken the IRIN in at least some of those cases should not be ruled out," Nadimi said.

More generally, he noted the accidents "show a major flaw" in the IRIN command and "possible flaws in indigenous warship designs and production methods."

"They are losing warships at such a pace in peacetime," Nadimi said. "Who knows how quickly they will lose ships in wartime!"