In August 1979, the 600-mile Fastnet race, which began in fine weather off the Irish coast, became for the men and women sailing it a terrifying ordeal. A Force 10, sixty-knot storm swept across the Atlantic with a speed that confounded weathermen, into the fleet of 303 boats. Now Rousmaniere, who was there, tells of the greatest disaster in the history of yachting. Photographs.