Question: What position did the man who drowned at a Australian beach named after a naval ship hold?

Context paragraphs:
Saginaw Valley Naval Ship Museum: The Saginaw Valley Naval Ship Museum is dedicated to documenting the history of the United States Navy.  The museum will be permanently housed in the USS "Edson", a retired United States Navy destroyer that has recently been converted to a museum.  The museum is located in Bay City, Michigan, United States.  The man responsible for this destroyer being opened for a museum is Mike Kegley, the president of the Saginaw Valley Naval Ship Museum, who has worked on the project for the last fifteen years.  This destroyer will be the main event for the museum as it has plans to expand into other exhibits in the years to come.  The vice president Richard Janke, the Secretary Mary Kegley, and the treasurer Mark Janke also run the museum.

USNS Marine Adder (T-AP-193): USNS "Marine Adder" (T-AP–193) was a troop ship for the United States Navy in the 1950s.  She was built in 1945 for the United States Maritime Commission as SS "Marine Adder, a Type C4-S-A3 troop ship, by the Kaiser Company during World War II.  In 1950, the ship was transferred to the Military Sea Transport Service of the U.S. Navy as a United States Naval Ship staffed by a civilian crew.  After ending her naval service in 1957, she entered the National Defense Reserve Fleet, but was sold for commercial use in 1967.  Renamed SS "Transcolorado, she was chartered by the Military Sealift Command as a civilian cargo ship designated T-AK-2005.

Pong Su incident: The "Pong Su" incident began on 16 April 2003 when heroin was smuggled from the "Pong Su", a North Korean cargo ship, onto an Australian beach.  Australian military special forces subsequently boarded the "Pong Su" in Australian territorial waters four days later.  The ship was suspected of being involved in smuggling almost 125 kg of heroin into Australia with an estimated street value of A$160 million.

Harold Holt: Harold Edward Holt, {'1': ", '2': ", '3': ", '4': "} ( ; 5 August 190817 December 1967), was an Australian politician and the 17th Prime Minister of Australia from 1966 to 1967.  He was born in Stanmore, New South Wales and won a scholarship to study law at the University of Melbourne.  Holt went into business as a solicitor, during which time he joined the United Australia Party (UAP).  In 1935, aged just 27, he was elected to parliament for Fawkner.  He held this seat until 1949, when he transferred to Higgins.  Holt spent 32 years in Parliament, including many years as a senior Cabinet Minister, but was Prime Minister for only 22 months before he disappeared in December 1967 while swimming at Cheviot Beach near Portsea, Victoria and was presumed drowned.

M80 Stiletto: The M80 Stiletto is an American prototype naval ship of a new generation type of ship utilizing advanced stealth technologies, it is manufactured and developed by American naval architecture and maritime engineering company and defense contractor the M Ship Company as an operational experimental ship testbed / class for The Pentagon’s Office of Force Transformation.  It is notable for its advanced Pentamaran hull design and sophisticated carbon fiber and advanced material composite construction, as well as its groundbreaking networked architecture.

Finnish minelayer Pohjanmaa: Pohjanmaa is a former minelayer of the Finnish Navy.  The sole member of her class, she was the flagship of the Finnish Navy as well as the largest naval ship in service in Finland until 2013.  The ship has an Finnish-Swedish ice class 1A so she can operate all year round.  During a crisis, the main task for "Pohjanmaa" would have been mine laying and acting as a command ship.  She also acted as a school ship for the Naval Academy cadets.  Part of their training includes an annual cruise abroad.

USNS Private Leonard C. Brostrom (T-AK-255): USNS "Private Leonard C. Brostrom" (T-AK–255) was a cargo ship for the United States Navy that was converted into a heavy lift cargo ship in the early 1950s.  She was built in 1943 for the United States Maritime Commission as SS "Marine Eagle, a Type C4-S-B1 tank carrier, by Sun Shipbuilding during World War II.  In 1948, she was transferred to the United States Army as USAT "Private Leonard C. Brostrom after Leonard C. Brostrom, a recipient of the Medal of Honor.  In 1950, the ship was transferred to the Military Sea Transport Service of the U.S. Navy as a United States Naval Ship staffed by a civilian crew.  After ending her naval service, she entered the National Defense Reserve Fleet in October 1980 and was sold for scrapping in June 1982.

Lighthouse and naval vessel urban legend: The lighthouse and naval vessel urban legend describes an encounter between a large naval ship and what at first appears to be another vessel, with which the ship is on a collision course.  The naval vessel, usually identified as of the United States Navy and generally described as a battleship or aircraft carrier, requests that the other ship change course.  The other party (generally identified as Canadian or often Irish and occasionally Spanish) responds that the naval vessel should change course, whereupon the captain of the naval vessel reiterates the demand, identifying himself and the ship he commands and sometimes making threats.  This elicits a response worded as "I'm a lighthouse.  Your call" (or similarly), a punchline which has become shorthand for the entire anecdote.

Achilles Point: Achilles Point (Te Pane o Horoiwi - "The head of Horoiwi") is a rocky point on the headland at the eastern end of the small sandy beach named Ladies Bay, Auckland, New Zealand.  The name 'Te Pane o Horoiwi' can also sometimes refer to the whole headland between St Heliers and Tamaki River estuary.  Achilles Point is named after a ship called HMNZS Achilles (70) which defeated the German pocket battleship Admiral Graf Spee in 1939.  The headland, from the point round to the Tamaki heads, was previously known as Te Pane o Horoiwi, named after Horoiwi who arrived in New Zealand on the Tainui canoe (waka).

Cheviot Beach: Cheviot Beach is a beach near Point Nepean in Victoria, Australia.  It was named after the SS "Cheviot", which broke up and sank nearby with the loss of 35 lives on 20 October 1887.

Supporting paragraphs: Harold Holt Cheviot Beach
Answer: Prime Minister