USS O-9 (SS-70) Underway
Photograph courtesy of Klein Sonar Co.
USS O-9 (SS-70) Underway
Photograph courtesy of Klein Sonar Co.
Date of Loss: 20 June 1941
Returned to Service: No
The keel for U.S.S. O-9 (SS-70) was laid at the Fore River Shipbuilding Co., in Quincy, MA on 15 February 1917. She was christened on 27 January, 1918 and commissioned just 6 months later, on 27 July, 1918. After performing coastal patrols for several months, she departed for a Great Britain, in order to conduct her first WWI war patrol. However the end of the war came before O-9 reached Europe. She performed training duties and travelled as far as the Panama Canal before being decommissioned on 25 June, 1931.
With World War II looming on the horizon, the U.S. Navy began a massive construction program. The 12 submarines of the Tambor-class were already nearing completion, and 73 Gato-class boats had been already been ordered, when O-9 was re-commissioned on 14 April, 1941. O-9 and her sisters were returned to service in order to provide training platforms for a submarine force that was certain to grow by leaps and bounds.
In all, nine O-class boats were recommissioned to serve as training submarines (O-1 through O-10, except for O-5, which had been sunk after a collision in 1923.) O-9, in particular, required extensive work, and still suffered mechanical problems even after being returned to service. On the morning of 20 June, 1941, O-9 and two of her sisters, O-6 (SS-67) and O-10 (SS-71) left as a group from the submarine base in New London, CT for the submarine test depth diving area east of the Isle of Shoals. Upon reaching their designated training area, O-6 made the first dive, followed by O-10. Finally, at 8:37, O-9 began her dive and slid beneath the surface of the Atlantic. By 10:32 O-9 had still not re-appeared, and the navy began to fear the worst.
That evening, their fears were confirmed when pieces of debris with the markings of the O-9 were recovered. With a water depth of 450 feet, the O-9 was thought to be crushed, since her hull was only designed to withstand depths of around 200 feet. Rescue operations were discontinued on 22 June, 1941, just two days later. The O-9 was never located.
Thirty three officers and crew were lost. No survivors.
This image is a 500 kHz sonar scan, which clearly shows the submarine (shadows are light, hard targets are dark). The bow is to the right with the stern to the left. It appears that the hull is crushed from just abaft the conning all the way to the stern. However, the forward hull appears intact:
This image is the same image, however it has been inverted (to make it easier to see) and slightly colored in order to enhance the detail.:
There are no plans to salvage the O-9. Her exact location is a closely guarded secret, and the area has been designated an official Naval burial ground.
Based on the information available on the O-9's poor material condition, as well as the condition of the wreckage, it is this author's opinion that the O-9 probably suffered an accident very different from most others researched here. The O-9 probably began to flood somewhere forward of the engine room. The hatch between the engine room and the rest of the submarine was secured immediately upon discovery of the flooding. However, this flooding resulted in the O-9 being pulled below her crush depth, and the watertight engine room section was crushed. The forward section filled with water and thus fell to the ocean floor intact, still attached to the flattened engine room section.
(Klein Sonar Website; U.S. Navy DANFS 5: 122)
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U.S. Peacetime Submarine Losses
The excellent work of Klein Sonar Co., and the many other people involved in the discovery of the O-9 are to be commended. The author would especially like to thank the kind people at Klein Sonar, who graciously allowed the use of their images.
This page last updated 31 January, 1998.
