HMS Racehorse was an 18-gun ship-rigged (i.e. three-masted) sloop of the Royal Navy. Originally the French ship Marquis de Vaudreuil, she was captured by the Royal Navy in 1757 and refitted as a survey vessel for the 1773 Phipps expedition towards the North Pole. Renamed HMS Thunder in 1775, she was captured back by the French in 1778.