Sometimes you’re intrigued by an ambitious goal — a marathon, for instance, or triathlon — but are hesitant to commit. If only you could see it in action first … . Well, if you’ve been intrigued by the idea of an ultra — a footrace longer than a marathon — then head to Bald Island this weekend and check out the Third Annual Badwater Cape Fear, where runners will be doing either a 50K or 51.4-mile run, most of it along the lonely coastline between Cape Fear and Fort Fisher.