According to reports, a U.S. Navy fast attack submarine engaged an Iranian Moudge-class Frigate, the IRIS Dena, using a Mk 48 heavy torpedo, which is known to be among the most devastating anti-ship weapons in the U.S. arsenal. Infrared footage of the engagement, recorded from the submarine’s periscope, shows a massive explosion ripping through the aft section of the nearly 312-foot-long warship off the coast of Sri Lanka.