Rare WWII Incident

On this day in 1945, a very rare underwater collision occurred between two American submarines.

USS Hoe (SS-258), while patrolling off Indochina at a depth of 60 feet, struck USS Flounder (SS-251). Flounder was at a depth of 65 feet. After the collision, Hoe broached the surface, while Flounder was forced deeper.

Here is the story, as told in the patrol reports of both submarines:

USS Hoe (SS-258):

“While at 60 foot, speed 1.8 kts, course north, Lat. 13-30.9 N, Long. 109-29.1 E. struck what I thought to be a rock. Ship took a four degree up angle and broached. Went to battle stations and blew all main ballast tanks. …On the way to the conning tower one look in the forward torpedo room showed that we had not holed the pressure hull. (The shock felt to me as though we had grounded forward on the starboard side.)”

A short time later, after sighting a ship and an airplane, Hoe submerged and returned to her patrol.

Flounder's side of the story:

“All clear on sound, all clear by periscope, depth 65 feet. Suddenly the whole ship gave a peculiar shudder. Started deep. 30 seconds later ship gave another shake and water started entering boat through the APR cable. Shear valve was closed and stopped leak. Sound soon reported a tremendous rush of air and high speed screws, starting and stopping on our starboard bow. By this time we had figured out that someone has run into us. Screws began to get fainter so at 1711, came to periscope depth and took a look. Calm seas, blue skies, nothing in sight. We were then convinced we had run into a Jap sub and we hoped that he had sunk.”

The mystery was only solved later, when the patrol reports of the two submarines were compared.

Thanks to the Submarine Force Museum, Groton, CT for publishing the original article on which this blog post is based. Official U.S. Navy images.