U.S. moving dozens of underwater crafts to Persian Gulf WASHINGTON - The Navy is rushing dozens of unmanned underwater craft to the Persian Gulf to help detect and destroy mines in a major military buildup aimed at preventing Iran from closing the strategic Strait of Hormuz in the event of a crisis, U.S. officials said. The tiny SeaFox submersibles each carry an underwater television camera, homing sonar and an explosive charge. The Navy bought them in May after an urgent request by Marine Gen. James Mattis, the top U.S. commander in the Middle East. Each submersible is about 4 feet long and weighs less than 100 pounds. The craft are intended to boost U.S. military capabilities as negotiations with Iran over its nuclear program appear to have stalled. Three rounds of talks since April between Iran and the five countries in the United Nations Security Council plus Germany have made little progress. Some U.S. officials are wary that Iran may respond to tightening sanctions on its banking and energy sectors, including a European Union oil embargo, by launching or sponsoring attacks on oil tankers or platforms in the Persian Gulf. Some officials in Tehran have threatened to close the narrow waterway, a choke point for a fifth of the oil traded worldwide. The first of the SeaFox submersibles arrived in the Gulf in recent weeks, officials said, along with four MH-53 Sea Dragon helicopters and four minesweeping ships, part of a larger buildup of U.S. naval, air and ground forces in the region aimed at Iran. The U.S. already has sent two aircraft carriers and a squadron of F-22 fighters to the Persian Gulf, and is keeping two U.S. army brigades in Kuwait. Though much of the buildup has been publicly acknowledged by the Pentagon, the deployment of the submersibles has not been publicly disclosed, apparently to avoid alerting Iran. The SeaFox is small enough to be deployed from helicopters and even small rubber boats, but it also can be dropped off the back of a minesweeper. It is controlled by a fiber optic cable and sends live video back to a camera operator. It can be used against floating or drifting mines, which Iran has used in the past. It operates up to 300 meters deep, and moves at speeds of up to six knots. But the $100,000 weapon is on a what amounts to a suicide mission. The "built-in, large caliber shaped charge" it carries destroys the mine but also the vehicle itself.