 However, "X2"s side cargoes have flooded, which causes them to spontaneously explode, destroying "X2" and killing her crew.The screenplay was based on the book "Above Us the Waves" by C. E. T. Warren and James Benson, which had been published in 1953.Director Ralph Thomas says the film was made because producer William MacQuitty "was very involved with the Navy and he loved submarines."