Question: What was the duration of the war that was in progress when the USS McAnn first served in the Atlantic Ocean?

Context paragraphs:
2012 Atlantic hurricane season: The 2012 Atlantic hurricane season was the final year in a consecutive string of three hyperactive seasons, although most of the storms were weak.  It is tied with 1887, 1995, 2010, and 2011 for having the third-most named storms on record.  It was also the second-costliest season, behind 2005.  The season officially began on June 1 and ended on November 30, dates that conventionally delimit the period during each year in which most tropical cyclones form in the Atlantic Ocean.  However, Alberto, the first system of the year, developed on May 19 – the earliest date of formation since Tropical Storm Ana in 2003.  A second tropical cyclone, Beryl, developed later that month.  This was the first occurrence of two pre-season named storms in the Atlantic basin since 1951.  It moved ashore in North Florida on May 29 with winds of 65 mph (100 km/h), making it the strongest pre-season storm to make landfall in the Atlantic basin.  This season marked the first time since 2009 where no tropical cyclones formed in July.  Another record was set by Hurricane Nadine later in the season; the system became the fourth-longest-lived tropical cyclone ever recorded in the Atlantic, with a total duration of 22.25 days.  The final storm to form, Tony, dissipated on October 25 – however, Hurricane Sandy, which formed before Tony, became extratropical on October 29.

USS Henry R. Mallory (ID-1280): USS "Henry R. Mallory" (ID-1280) was a transport for the United States Navy during World War I.  She was also sometimes referred to as USS "H. R. Mallory or as USS "Mallory.  Before her Navy service she was USAT "Henry R. Mallory as a United States Army transport ship.  From her 1916 launch, and after her World War I military service, she was known as SS "Henry R. Mallory for the Mallory Lines.  Pressed into service as a troopship in World War II by the War Shipping Administration, she was torpedoed by the  in the North Atlantic Ocean and sank with the loss of 272 men—over half of those on board.

List of Atlantic hurricane records: Since the reliable record keeping of tropical cyclone data within the North Atlantic Ocean began in 1851, there have been 1,505 systems of at least tropical storm intensity and 879 of at least hurricane intensity.  Though a majority of these tropical depressions have fallen within climatological averages, prevailing atmospheric conditions occasionally lead to anomalous tropical systems which at times reach extremes in statistical record-keeping including in duration and intensity.  The scope of this list is limited to tropical cyclone records solely within the Atlantic Ocean and is subdivided by their reason for notability.

USS McAnn: USS "McAnn" (DE-179) was a "Cannon"-class destroyer escort built for the United States Navy during World War II.  She served in the Atlantic Ocean and provided escort service against submarine and air attack for Navy vessels and convoys.

HMCS Charlottetown (FFH 339): HMCS "Charlottetown" is a "Halifax"-class frigate that has served in the Royal Canadian Navy since 1995.  "Charlottetown" is the tenth ship in her class which is based on the Canadian Patrol Frigate Project.  She is the third vessel to carry the designation  .  "Charlottetown", assigned to Maritime Forces Atlantic (MARLANT) and homeported at CFB Halifax, serves on missions protecting Canada's sovereignty in the Atlantic Ocean and enforcing Canadian laws in its territorial sea and Exclusive Economic Zone.  "Charlottetown" has also participated in several NATO missions, patrolling the Atlantic Ocean as part of Standing Naval Force Atlantic (STANAVFORLANT) and its successors Standing NATO Maritime Group 1 and 2 (SNMG1 / SNMG2).  "Charlottetown" has also been deployed on missions throughout the Atlantic and to the Indian Ocean, specifically the Persian Gulf and Arabian Sea on anti-terrorism operations.

USS Elokomin (AO-55): USS Elokomin (AO-55) was a "Cimarron"-class fleet oiler acquired by the U.S. Navy during World War II.  She served her country primarily in the Atlantic Ocean, Mediterranean Sea, and North Atlantic Ocean Theatre of Operations, and provided petroleum products where needed to combat ships.

World War II: World War II (often abbreviated to WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier.  It involved the vast majority of the world's countries—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis.  It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries.  In a state of total war, the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, erasing the distinction between civilian and military resources.

The Spirit of Butts' Farm: The Spirit of Butts' Farm (also known as TAM 5) was the first model aircraft to cross the Atlantic Ocean on August 11, 2003.  The aircraft was launched from Cape Spear near St. John's, Newfoundland and Labrador, and landed at Mannin Beach near Clifden, Ireland 38.9 hours later.  It was recognized by the FAI as a double world record flight for its duration of 38h 52 min 19 sec and straight-line distance of 1881.6 mi using an autopilot, and using the Argos System for telemetry to track the flight's progress; the team's use of technology also spurred the FAI to create new record categories.  The aircraft was controlled by autopilot for >99% of the flight in a manner similar to that used by the Insitu Aerosonde UAV "Laima" that crossed the Atlantic in 1998.  The flight used 99.2% of its fuel and left only 1.5 USfloz (or 44 minutes of flight time) remaining when it reached its destination.

USS Laning (DE-159): USS "Laning" (DE-159/APD-55/LPR-55) was a "Buckley"-class destroyer escort in the United States Navy during World War II where she served in the North Atlantic Ocean, protecting Allied ships from German submarines and other threats.  She also served in the Pacific Ocean with Underwater Demolition Teams.  During the Korean War she served as a training ship, and, in 1975 she was scrapped.

USS South Dakota (BB-57): USS "South Dakota" (BB-57) was a battleship in the United States Navy, in active service from 1942 until 1947.  The lead ship of her class, "South Dakota" was the third ship of the US Navy to be named in honor of the 40th state.  The four ships of the class are considered to be the most efficient battleships designed under the limitations of the Washington Naval Treaty.  During World War II, the battleship first served a tour in the Pacific theater, where it fought in two battles in 1942 that earned the ship and its crew a Navy Unit Commendation before returning to New York in December 1942 for an overhaul and battle repairs.  In May 1943, "South" "Dakota" joined British Home Fleet patrols in the North Atlantic and Arctic Oceans before sailing again to the Pacific in August 1943.  There, "South Dakota" participated in combat operations preparatory to the invasion of Japan until returning to the United States in October 1945.

Supporting paragraphs: USS McAnn World War II
Answer: 1939 to 1945