The father of a 10-year-old boy pulled from dangerous surf off the California coast says he will be "forever grateful" to the teenage lifeguard who risked his own life to save his son.
Video of the dramatic rescue at Seabright Beach in Santa Cruz has been viewed around the world after 16-year-old lifeguard Ryder Williams sprinted into pounding waves to reach Nathaniel Rai, who had been swept out by powerful surf.