Key point: An outgrowth of the Iran-Iraq War.
The orders from the Joint Chiefs of Staff were clear: the Iranian frigate Sabalan must die.
On April 14, 1988, the frigate USS Samuel B. Roberts had run into an Iranian mine while attempting to extricate herself from a minefield. The blast tore open a 21-foot long hole in her hull and wounded ten sailors. Only a heroic damage control effort kept the frigate afloat.
This was deemed the last straw after ten months of skirmishes between U.S. ships and Iranian forces in the Persian Gulf.
It was by then the eighth bloody year of the Iran-Iraq War, in which Iran had taken to attacking commercial shipping in the Gulf in retaliation for Arab support for Iraq.
Starting in June 1987, U.S. ships began escorting commercial convoys in the Gulf under operation “Earnest Will.” Meanwhile, special operators in helicopters caught an Iranian ship at night laying mines and captured a logbook proving Iranian involvement—as recounted in this earlier article.
Following the Roberts mining, President Reagan wanted to launch a more punishing retaliation. Attacks on actual Iranian soil were deemed too escalatory. Instead, for Operation Praying Mantis two Iranian oil platforms—used to surveil commercial shipping with their radars and stage motorboat attacks—were marked for termination. And the Sabalan.
The 1,500-ton Saam-class frigate was one of three built by Vosper in the UK for Iran during the 1970s, and was armed with a rapid-firing 4.5” gun and Italian-built Sea Killer cruise missiles on a stern-mounted launcher (picture here). Using an Iranian modification of the outdated Sea Killer called the Sea Dawn, the frigates had struck six Iraqi merchant ships in a five-month period in 1986-1987.