USS San Diego (CA-6)

World War I armored cruiser sunk by German mine in 1918. Six lost.
by Matthew Anderson

Year Built


Year Sank



110 ft (33.5 m)

Difficulty Level


USS San Diego (CA-6)

Wreck Location

USS San Diego lies off Cherry Grove on Fire Island, New York in 110 feet of water. The surrounding location is home to a large number of shipwrecks including the SS Oregon, a Cunard Liner lost in a collision in 1886. Also nearby is the crash site of TWA Flight 800. San Diego is a popular diving site well documented and heavily visited. The surrouding waters are abundant in large marine life. Crevases in the wreck offer protection to anenomies, lobsters and fish.

~ GPS Shipwreck Location ~
Latitude:   40° 33' 0.36" N      Longitude:   -73° 0' 28.3896" W


Over the years, USS San Diego has obtained considerable damage. As she sank, San Diego capsized and rolled completely upside down. Everything from her boat deck up is now either crushed or buried in massive amounts of silt. The ship lies "turtle" or upside down on the sea floor. Furthermore, Naval vessels and aircraft attacked the wreck with bombs shortly after the sinking, mistaking her for U-156. San Diego's hull has also begun caving in and large sections of the hull no longer retain the classic "U" shape most ships are known for. This may have occurred due to corrosion coupled with the damage sustained by mistaken identity during the war. The wreck is also an abundant home for lobsters. Although San Diego lies in shallow water where sunlight still penetrates the ocean waters, she is a wreck to be cautious around, as multiple divers have lost their lives in preceding times. Therefore, it's best to have experience first.


USS San Diego (CA-6)

USS California (ACR-6) was a Pennsylvania-class armored cruiser built in 1907 at the Union Iron Works in San Francisco, California. She originally served in the Pacific and was on duty during civil unrest in Nicaragua and the Mexican Civil War. On September 1, 1914, she was renamed USS San Diego so as to free her name for a new battleship. She served as flagship of the Pacific until 1917, when she was placed in reserve. Upon the American entry into World War I, San Diego was reactivated and moved to the Atlantic to escort Allied convoys to Europe, providing protection against German submarines. On July 19, 1918 however, while enroute to join her designated convoy, San Diego likely hit a mine off Long Island, New York, laid earlier by German submarine U-156. She sank in 28 minutes killing six servicemen. She was one of the few major navy vessels the United States lost during the first World War.


2 Comments & Ratings

anonymous by Linda Poinboeuf Denyer on 3/5/2018
Map was rated 5 stars by reviewer.

My father, Julius Joseph Poinboeuf, was on board the ship when she was hit. He was injured, but recovered. He later served in WWII as well.

anonymous by Anonymous on 7/16/2021

According to Wikipedia, the German submarine U-156 was launched in May 21, 1941. I don’t think it laid the mine that sunk the San Diego.

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