More than 50 people dressed in Edwardian hats wearing silver medal replicas around their necks celebrated Geoffrey Carr's medal in the men's four rowing crew on Saturday.
They cruised in a Victorian steam cruiser called the S.L. Streatley, which itself is 100-years-old, stopping at Windsor Bridge for a champagne toast to their sporting relative.
On board were family members including his only surviving child Jane Jox, 90, along with grandchildren and great, great, great grandchildren.
Windsor-born grandson Geoffrey Carr, 53, said: "We are all so proud of what he achieved as an Olympian 100 years ago today.
"There are members of our family here that we have not seen all together before and we were on the river at the time they won the men's four."
Geoffrey senior was selected aged 26 in the men's four to represent Great Britain at the 1912 Games and was the boat's coxswain, steering them to a podium spot.
Mr Carr junior, who now lives in Gloucestershire, has inherited his grandfather's silver medal, and said they did the boat ride after failing to get tickets to the 2012 Games.
The former Windsor Boys' School pupil was 10 when his grandfather died aged 82 in 1968, but has fond memories of him.
He said: "He was very quiet, unassuming and modest and never spoke about his achievement and my grandfather would think this was an awful lot of fuss to be made."
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