The Black Stallion (1979)

http://www.imdb.com/title/tt0078872

While traveling with his father, young Alec becomes fascinated by a mysterious Arabian stallion that is brought on board and stabled in the ship he is sailing on. When the ship tragically sinks both he and the horse survive only to be stranded on a deserted island. Alec befriends the horse, so when finally rescued both return to his home where they soon meet Henry Dailey, a once successful trainer. Together they begin training The Black to race against the fastest horses in the world.