The last time the Summer Olympics were held in London was 64 years ago, in 1948, after a twelve year hiatus due to World War II. My father's cousin and uncle participated in the Sailing competition in Torbay, on the south coast of England. Wikipedia has a detailed description of Sailing at the 1948 Summer Olympics, where it notes that Hilary Smart (1925 - 2000) and his father Paul Smart (1892 - 1979) won the Gold Medal in the "Star" Event.
The following screenshots are from the detailed page about this race at Wikipedia (accessed July 13, 2012)
I love that the name of their sailboat was "Hilarious." Having known my dad's cousin Hilary, that's his sense of humor shining through.