A new, key addition to American-led naval efforts to ensure Mideast oil keeps flowing has emerged as an unusual mix of a ship combining decades' worth of wear and tear with state-of-the-art technology and a largely civilian crew.

After winning a reprieve from the scrapyard, the USS Ponce was reborn through a rush retrofit earlier this year and turned into a floating base prowling the waters of the Persian Gulf. It is now getting its biggest workout since refurbishment as the centerpiece for sweeping anti-mine naval exercises under way that serve as a very public warning to Iran. The Islamic Republic has threatened to shut the Gulf's entrance at the Strait of Hormuz, the route for a fifth of the world's oil supplies, and would likely use mines to do so.

Anti-mine divers on practice drills deployed in small boats off the Ponce's stern gate early Saturday, and MH-53 minesweeping helicopters launched from the ship kicked up sea spray as they hauled mine-detecting equipment through the water.