Except for the doughty Chichester who doesn't waste much time canoodling the ego, most lone seafarers are apt to be crashing bores -- not so Miss Walker, a 28 year-old Briton who sailed non-stop from Wales to Newport, R.I. in a 30-foot sloop. Miss Walker is blunt, convivial and thoroughly engaging. She ticks off the ""why"" of her bumptious adventure immediately: she was bored by her job; a love affair was doomed; and she wanted to impress people, particularly men, who seem to be bowled over by things only men do. First day out she ""had a little cry and wished [she] wasn't going,"" but once underway she hove to and coped -- although there was one stormy time when she didn't want to ""fight with ropes and sails"" but just waited below for ""the nasty weather to go away."" There's plenty of stringent nautical maneuvers and en route she experimented with eating habits, read, and analyzed her reactions to isolation and personal fears. She could never turn back: ""I could just hear the patronizing sympathy from the men...I am not brave enough to be a coward..."" A brisk sail with a lib-jib.