Robert Marx, 30, first ran away from home at 9. At 13 he left for good, took up dive-by-night salvage in Connecticut, and went to California to skin dive, where treasure diving became his first love. After the world fame that came with his off shore discovery of the Monitor in South Carolina he went to Madrid where he joined up with Carlos Etayo who was building an exact replica of Columbus' diminutive ship Nina, planning to sail it to America. She was so plagued and so unseaworthy that she made the longest Atlantic crossing in navigation history -- 77 days. Columbus did it handily in 36. However, while jinxes settled like barnacles on the Nina II, none have attached themselves here in this admirably vigorous account of what a man can do with his life.