Photos from Iran’s Great Prophet 5 war games are popping up on the interwebs; Uskowi on Iran has a good collection. These show Iranian small boat swarms attacking a hapless target vessel with 107mm rockets and machine gun fire.
The Islamic Republic uses its growing fleet of small boats and fast attack craft in pursuit of a doctrine of “access denial,” according to a 2009 Office of Naval Intelligence report I've posted below the jump; part of the “anti-access” challenge that figured so prominently in the 2010 QDR.
As ONI points out, small boat tactics are not particularly new and should be familiar to anybody who has read accounts of U.S. PT boats or German E-Boat tactics during World War II. Iranian small boats will operate near shores using geography to mask their presence, use hit and run attacks, will operate in groups and attack ships with limited mobility in congested sea lanes, straits or entering or leaving port.