USS Caiman (SS-323), a Balao-class submarine, was a ship of the United States Navy that was later transferred to the Turkish Naval Forces in 1972 under the Security Assistance Program, where she was recommissioned as the third TCG Dumlupınar.

Originally Blanquillo, the vessel was renamed on 24 September 1942 after the caiman, a fresh water alligator inhabiting the Amazon River, and launched on 30 March 1944 by Electric Boat Co., Groton, Connecticut; sponsored by Mrs. R. C. Bonjour; commissioned 17 July 1944.

Pausing at Saipan to put ashore her severely ill commanding officer and embark his relief, the submarine pushed on to the South China Sea, where she combined offensive patrol with lifeguard duty as a part of air-sea rescue operations to save aviators downed in air strikes on enemy-held territory.

Aggressive American submarine and naval air attack had already greatly reduced the Japanese merchant fleet; hence Caiman made no contacts on this patrol, from which she returned to Fremantle, Australia, on 22 January 1945 to refit.

Luckily, her crew was able to ground the submarine on a nearby bank, thus preventing the tragedy that befell the previous TCG Dumlupinar in 1953, the wreck site of which lay just 28 nautical miles (52 km; 32 mi) away.