Isaac Thomas Thornycroft
| Olympic medal record | ||
|---|---|---|
| Men's Water motorsports | ||
| Gold | 1908 London | Class B |
| Gold | 1908 London | Class C |
Isaac Thomas "Tom" Thornycroft (22 November 1881 – 6 June 1955) was an English motorboat racer who competed in the 1908 Summer Olympics representing Great Britain.
He won two gold medals in the only motor boat competitions included in the Olympics as helmsman of the Gyrinus II, which was designed by his father Sir John Isaac Thornycroft.
He became a yacht designer and helmsman of J Class racing yachts.