HMS J1 was a J-class submarine operated by the Royal Navy and the Royal Australian Navy.
HMAS J1 in 1919
J1 being refitted at Cockatoo Island Dockyard in 1919
The J-class submarines were seven submarines developed by the Royal Navy prior to the First World War in response to claims that Germany was developing submarines that were fast enough to operate alongside surface fleets. Six were completed during mid-1916, while a seventh entered service at the end of 1917.
Six J-class subs next to their supply ship HMAS Platypus in 1919
Wreck of HMAS J7 at Sandringham Yacht Club marina