The steam yacht Ena is a steam yacht that was built in 1900 for Thomas Dibbs, the commodore of the Royal Sydney Yacht Squadron. It was used as his private vessel for entertaining guests on Sydney Harbour and Pittwater until the beginning of World War I. In 1917 the yacht was purchased by the Royal Australian Navy (RAN) and used as the auxiliary patrol vessel HMAS Sleuth in the waters around the Torres Strait and Thursday Island, before later being used as a training ship tender based in Sydney.