The Coast Guard rescued a man in a life raft after his sailboat sank approximately seven miles south of Diamond Head, Tuesday. Watchstanders at the Coast Guard Sector Honolulu command center overheard a brief mayday call over VHF channel 16 at 7:43 p.m., with no additional information. Sector Honolulu received a call from a woman at 9:05 p.m., stating her friend had gone out sailing Tuesday evening in his 41-foot sailing vessel, Esperanza, and had not returned. Sector Honolulu diverted a 45-foot Response Boat-Medium boat crew at 9:16 p.m., from Coast Guard Station Honolulu to begin a search. At 9:44 p.m., the RB-M crew noticed a blinking…