In 1988 AShMs were fired by both American and Iranian forces in Operation Praying Mantis in the Persian Gulf. During this naval battle, several Iranian warships were hit by American AShMs (and by the US Navy's Standard missiles—surface-to-air missiles which were doing double-duty in the anti-ship role). The US Navy hit the Iranian Navy frigate Sahand with three Harpoon missiles, four AGM-123 Skipper rocket-propelled bombs, a Walleye TV-guided bomb, and several "iron bombs". Despite the large number of munitions and successful hits, "Sahand" did not sink until fire reached her ammunition magazine, causing it to detonate, sinking the vessel. In the same engagement, American warships fired three Standard missiles at an Iranian Navy corvette. This corvette had such a low profile above the water that a Harpoon missile that arrived several minutes later could not lock onto it with its targeting radars.