Johann Maria (Hannie) Termeulen-Boomstra ( Wiesbaden , February 18th 1929 - Amsterdam , March 1 2001 ) was a swimmer. She achieved her greatest successes swim just after theSecond World War and at the beginning of the fifties of the 20th century . Highlights of her career were the two silver medals at the Olympic Games of 1952 in Helsinki on the 100 and the 4x100-meter freestyle .