how shelley tyre looked forward to it. >> tortolla, the british virgind islands., diving, postcard perfect beaches. how shelley tyre look forward to it. she and her husband david had chartered a sailboat with their friends, the thwaite's. a week of diving and sailing, whichever called their fancy. upon arrival here in tortolla, the men set out to arrange for the charter and rental of their scuba gear. the women went out for provisions for their sailboat, and went to the marina for their holiday is see. no one in that group could say that anything was amiss. it was, by all accounts, the weak gun hoeing around the caribbean that all had hoped for. salt island, peter island, the wreck of the rhtne. they set a course for cooper island at eight site known as the twin racks. keith royle has been down to the twin racks hundreds of times. >> there are two racks sitting there, with a small gap between them. between that is the fish life. >> david swain and his friend christian thwaite were both certified instructors. between them, they have 1000 dives under their belt. she