HMAS Waterhen (D22) was a W-class destroyer of the Royal Australian Navy and one of the ships of the Scrap Iron Flotilla. Stephen H. T. Arliss was her captain from 19 October 1929 until he was relieved on 29 July 1931.
Swain was in command at the end of her service. She was then on the Tobruk run. The evening before she sank, dive bombers holed her off Sollum and left her disabled. She sank under tow on 30 June 1941. HMS Defender took the crew off, and no one was killed.
Waterhen was the first RAN ship lost to enemy action in the war. No single aircraft is credited with the sinking. The loss was in the Mediterranean, off Sollum, and it was not a Pacific action.
