those massive joint u.s.-south korean exercises took a live fire turn today, ships and guns aiming their sights in a mock attack on an abandoned submarine off the coast of south korea. it is a suspected sinking of a south korean ship by a north korean submarine, way back in march, that started the latest round of -- of tension and in fact triggered the exercises. earlier today, we spent some time on another u.s. ship, here's a bit of what we saw and heard. the destroyer, the uss mccampbell is this front line of defense between north korea and the rest of the ships in the huge naval exercise. the main job is air defense. it can spot any hostile fighter plane or other aircraft coming from north korea and deal with it. a secondary role, spotting any hostile ships or submarines and can also handle those. so far, in the last few days of