Rivales (1984)

Steve Lucas is a nineteen year old who is filled with the burning resentment of being forced to live in his brother's shadow. His brother Adam, is burdened by his father's desire for glory, and must win The Coolangatta Gold Tri-Aquathon, It is the greatest endurance test of them all: a marathon involving a 20 kilometer beach run, 6 kilometer swim and a 17 kilometer surf ski from Surfers Paradise along the golden arc of beach to Coolangatta and back to the start. The Coolangatta Gold is a story of human endeavor and endurance against overwhelming odds.