U-156: Its Mine Sank the USS San Diego and It Shelled a Massachusetts Town

A mine they U-156 set is credited with sinking the armored cruiser USS San Diego, the largest warship the United States lost during World War I.

On July 21, 1918, the U-156 surfaced and fired shots at the town of Orleans, Massachusetts, and several nearby merchant vessels.  She sank a tugboat, the Perth Amboy, and four barges.  HS-1L flying boats and R-9 seaplanes were dispatched from Chatham Naval Air Station and dive bomber the U-156, but the bombs failed to explode.

The attack on Orleans was the only Central Powers attack on the U.S. mainland during the war. and it was the first time a foreign power's artillery had shelled the continental U.S. since the Siege of Fort Texas in 1846.  It was also the first time American pilots had engaged an enemy vessel in the West Atlantic.

A Lot of Firsts.  --Cooter

U-156-- Part 1: Originally Built to Carry Cargo Between the U.S. and Germany

From Wikipedia.

Was commissioned 22 August 19 1917.  Responsible for sinking 44 Allied ships (including one warship) and damaging three others.  It also was the German participant in the attack on Orleans, Massachusetts.

Was built in Bremen, Germany, one of the seven submarines built in the Deutschland-class designed to carry cargo between the United States and Germany.  Five of them, including the U-156 were converted into long-range cruiser U-boats with 5.9-inch deck guns.

On 15 June 1918, the U-156  slipped through the North Sea and into the Atlantic Ocean, heading for Long Island and then to New York harbor with orders to lay mines.  Records show that she lay a field of mines off the south shore of Long island just east of the Fire Island Lightship.

On 8 July it scuttled the Norwegian-owned Manx King

A mine laid by the U-156 is credited with sinking the armored cruiser USS San Diego on July 19, 1918, about ten miles southeast of Fire Island, New York.

--DaCoot

USS San Diego-- Part 4: Court of Inquiry Determines It Was a Mine

In August, the Navy Court if Inquiry appointed to investigate the loss of the cruiser concluded that the San Diego had been sunk by a mine..  Part of this was based on the fact that six contact mines had been found in the vicinity of where it sank.

The German submarine U-156 had earlier laid a number of mines along the south shore of Long Island and the sinking of the San Diego was attributed to her.

In 1999, a theory was advanced that a German spy by the name of Kurt Jahnke had planted explosives aboard the San Diego and caused its sinking.  This claim has been contested by the Naval Historical Center.

--Cooter

World War I Chronology-- July 1918: USS San Diego Hits Mine and Sinks

JULY 19

The armored cruiser USS San Diego hits a mine and sinks off Fire Island, New York, with the loss of six lives.

The USS San Diego was originally the USS California (ACR-6) and later renamed USS San Diego to free up the name California for a new battleship.  Commissioned 1 August 1904.  503 feet 11 inches length, beam 69 feet 6 inches.  Main armament four 8-inch rifles, fourteen 6-inch rifles.

Was renamed USS San Diego on 1 September 1914 in order to free up the name for the battleship USS California (BB-44) which was later at Pearl Harbor when it was attacked in 1941.

Served in the Pacific fleet until a boiler explosion in January 1915 put her at Mare Island.  Ensign Robert Cary and Fireman Second Class Telesforo Trinidad received Medals of Honor for the event.  Afterwardsshe was a popular attraction at the Panama-California Exposition in San Diego, Ca. 1 January 1915 to Jan. 1, 1917.

She was put into reserve status shortly thereafter until the beginning of World War I.

--Cooter