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