The United States has failed to win a medal on the 3-meter springboard for just the third time since it became an Olympic sport in 1908. American Mark Ruiz was expected to carry on the legacy left by Greg Louganis. But instead China's Xiong Ni joined Louganis as the only men's diver to defend his title in the event, winning gold yesterday. One man who was watching the action with heightened interest is Minnesota's only Olympic medalist in the sport. Craig Lincoln won a bronze medal on the three meter spring board at the 1972 Olympics in Munich, Germany.