The Seawolf-class attack submarine USS Connecticut. US Navy A US submarine hit an underwater object in October, for reasons that were initially a mystery. The Navy concluded Monday the USS Connecticut hit an uncharted hill beneath the surface. Chinese state media are not satisfied, and without evidence floated the idea of a nuclear spillage. Chinese state media are casting doubt on the US account of what happened to a nuclear submarine that collided with an object last month. US Navy investigators concluded Monday that the nuclear-powered attack submarine USS Connecticut hit an uncharted underwater hill while patrolling in international waters