Steven Callahan survived for 76 days adrift in an inflatable life raft. This 2002 photo shows Callahan with an improved life raft he designed after his ordeal. While enduring shark attacks, rain and helpless drifting, Callahan dreamed of a better survival vessel. Once he returned to land, he spent almost two decades designing this one, featuring a rigid exterior, a removable canopy and a sail. (Associated Press)
