Question: HMAS "Platypus" was a submarine depot ship and base ship operated by the Royal Australian Navy (RAN), ordered prior to World War I to support the Australian submarines originally known as just AE1, HMAS "AE1, was an "E"-class submarine of which organization?
Context: HMAS "Protector" (ASR 241) was a Royal Australian Navy (RAN) trials and submarine rescue ship.  Built in 1984, the ship was initially operated by the National Safety Council of Australia as MV "Blue Nabilla.  She was purchased by the RAN in 1990 for use as a surveillance, training, and diving support vessel.  During her military career, "Protector" supported the trials of the "Collins"-class submarine s, and was involved in a search for the shipwreck of the World War II cruiser HMAS "Sydney" .  The ship was decommissioned in 1998 and, while still owned by the Commonwealth, she is provided to Defence Maritime Services to allow them to support Navy activities under contract.  Renamed Seahorse Horizon", the ship is operated by Defence Maritime Services out of HMAS "Creswell" as a training and Fleet support vessel. HMAS "Platypus" was a submarine depot ship and base ship operated by the Royal Australian Navy (RAN) between 1919 and 1946.  Ordered prior to World War I to support the Australian submarines "AE1" and "AE2", "Platypus" was not completed until after both submarines had been lost, and she was commissioned into the Royal Navy from 1917 to 1919. HMAS "AE1 (originally known as just AE1") was an "E"-class submarine of the Royal Australian Navy (RAN).  She was the first submarine to serve in the RAN, and was lost at sea with all hands near East New Britain, Papua New Guinea, on 14 September 1914, after less than seven months in service.  The wreck of the submarine has never been found, despite several searches. HMAS "Grantala was a hospital ship operated by the Royal Australian Navy (RAN) during World War I.  She was launched in 1903 by Armstrong Whitworth Company for the Adelaide Steamship Company.  The ship operated in Australian waters from 1903, and was requisitioned by the RAN on 7 August 1914.  She was returned to her owners in 1915, then was sold and renamed Figuig".  The ship was scrapped in 1934. HMAS "Ovens" (S 70) was an "Oberon"-class submarine of the Royal Australian Navy (RAN).  She was one of six "Oberon"s built for the Royal Australian Navy by the Scottish Scotts Shipbuilding and Engineering Company, and entered service in 1969.  The vessel was named for Irishman and Australian explorer John Ovens (1788-1825) and for whom the Victorian river Ovens was named.  During her career, "Ovens" was the first RAN submarine to deploy with the ANZUK force, and the first RAN submarine to fire an armed Mark 48 torpedo, sinking the target ship "Colac" .  The boat was decommissioned in 1995, and is preserved at the Western Australian Maritime Museum as a museum ship. HMAS "AE2" (originally known as "AE2") was an "E"-class submarine of the Royal Australian Navy (RAN).  One of two submarines ordered for the fledgling navy, "AE2" was built by Vickers Armstrong in England and was commissioned into the RAN in 1914.  Together with her sister submarine, HMAS "AE1" , the boat then sailed to Australia in what was, at the time, the longest voyage ever undertaken by a submarine. HMAS "Upolu" was a submarine depot ship operated by the Royal Australian Navy (RAN) during World War I.  She was built by Fleming & Ferguson, Paisley, Scotland in 1891, for the Union Steam Ship Company.  She was requistioned by the RAN on 18 August 1914 and converted into a submarine depot ship and after a short commission, she was returned to her owners on 9 December 1914.  She was sunk in a collision with the "Lienhsing" off the Shantung Promontory on 12 August 1930. HMAS "Platypus" is a former Royal Australian Navy (RAN) submarine base, located at 118 High Street, North Sydney with moorings in Neutral Bay , a suburb of Sydney in New South Wales, Australia.  It was located upon the site of the Royal Australian Navy Torpedo Maintenance Establishment (RANTME).  Following remediation and refurbishment, it is to open for public use as Sub Base Platypus in mid-2018. HMAS "Melbourne" was a Town class light cruiser operated by the Royal Australian Navy (RAN).  The ship was laid down by Cammell Laird at Birkenhead in England in 1911, launched in 1912 and commissioned in 1913.  At the start of World War I, "Melbourne" was involved in attempts to locate the German East Asia Squadron, and participated in the capture of German colonies in the Pacific, before being assigned to the North America and West Indies Stations.  In 1916, the cruiser joined the Grand Fleet in the North Sea, where she remained for the remainder of the war.  "Melbourne" spent late 1919 and early 1920 in reserve, then was flagship of the Royal Australian Navy from 1920 until 1928, except for a second period in reserve during 1924 and 1925.  HMAS "Melbourne" paid off in the United Kingdom on 23 April 1928, and was scrapped in 1929. HMAS "Orion" (S 61) was an "Oberon" class submarine of the Royal Australian Navy (RAN).  One of six submarines ordered by the RAN during the 1960s, "Orion", named after the constellation in a break from ship-naming tradition, was built in Scotland and commissioned in 1977.  "Orion" was one of two Oberon-class submarines designed for intelligence gathering and conducted regular patrols in Soviet, Indian and Chinese waters to gather information regarding enemy capabilities.
Answer: Royal Australian Navy (RAN)