In Arthur Conan Doyle’s The Sign of the Four, the steam launch used in the Thames chase is called Aurora.
Holmes, Dr Watson, Inspector Athelney Jones, and their companions pursue Jonathan Small and his accomplice along the River Thames after the murder of Bartholomew Sholto. The chase takes place at night, and the faster launch Aurora becomes central to the pursuit.
The boat is connected with the criminal group’s attempt to escape after taking the Agra treasure. Doyle uses the river sequence to add speed and physical action to a mystery otherwise driven by testimony, deduction, and the history of the stolen fortune.
Aurora is sometimes confused with the treasure ship mentioned in the story’s backstory. The launch is the craft involved in the London pursuit, while the Agra treasure comes from events associated with the Indian Mutiny. The novella was published in 1890 as Holmes’s second major case.