A Fresno man died when his 15-foot outboard motorboat capsized off Santa Cruz and his two companions were rescued after an accident that one official said the victim may have survived had he worn a life jacket. Leo Joseph Keller, 41, and Danny Tallabas, 39, both of Fresno, who were also aboard the boat when it overturned, were able to swim ashore and were taken by helicopter to a Santa Cruz hospital, where they were released after treatment for shock and exposure. But Leo Joseph Keller Jr., 20, son of the elder Keller, was pronounced dead. "Most of the wreckage was on the beach, and no flotation devices were found anywhere," state park lifeguard Jay Butki said. "The whole tragedy could have been averted if they'd taken the precaution of wearing personal flotation devices."