Compiled by Paul W. Wittmer and Charles R. Hinman, originally from:

U.S. Submarine Losses World War II, NAVPERS 15,784, 1949 ISSUE

[Editor's note: The wreck of USS Robalo was discovered in May of 2019, necessitating a revision of some of the information contained below.]

ROBALO under Cdr. M. M. Kimmel, departed Fremantle on 22 June 1944 to conduct her third war patrol in the South China Sea in the vicinity of the Natuna Islands. After traversing Makassar and Balabac Straits, she was to arrive on station about 6 July, and stay there until dark on 2 August 1944.

On 2 July a contact report stated ROBALO had sighted a FUSO class battleship with air cover and two destroyers for escort in 3° 29'N, 119° 26'E, just east of Borneo. No other messages were received from ROBALO and when she did not return from patrol, she was reported as presumed lost.

The following information was received via the Philippine guerrillas and a U. S. Navy enlisted man who was a prisoner of war at Puerto Princesa Prison Camp, Palawan, P.I. On 2 August 1944, a note dropped from the window of the prison cell in which survivors from ROBALO were held was picked up by an American soldier who was in a work detail and given to H. D. Hough, Y2c, USN, another prisoner. On 4 August 1944, Hough contacted Mrs. Trinidad Mendosa, wife of guerrilla leader Dr. Mendosa, who furnished further information on the survivors. From these sources, he put together the following facts.

ROBALO was sunk 26 July 1944, two miles off the western coast of Palawan Island [Editor's note: With the recent discovery of the wreck, this location is known to be incorrect.] as a result of an explosion of her after battery. [Editor's note: According to the divers who found the wreck, the explosion that sank Robalo occurred much farther aft, in the vicinity of her aft torpedo room.] Four men swam ashore, an officer and three enlisted men: Samuel L. Tucker, Ens.; Floyd G. Laughlin, QM1c; Wallace K. Martin, SM3c, and Mason C. Poston, EM2c. They made their way through the jungles to a small barrio northwest of the Puerto Princesa camp. They were captured there by Japanese Military Police, and confined in the jail. They were held for guerrilla activities rather than as prisoners of war, it is said. On 15 August 1944, they were evacuated by a Japanese destroyer, and no other information is known regarding their destination or whereabouts. It is possible that they were executed by the Japanese or that the destroyer in which they were embarked was sunk. At any rate, they were never recovered, and their note stated that there were no other survivors. It is doubted that a battery explosion could be sufficiently violent to cause the sinking of the ship and it is expected that the loss of ROBALO was caused by striking an enemy mine.

Note: Robalo was lost off the east coast of Balabac Island. The coordinates shown below are approximate, and may not reflect the actual location of the recently discovered wreck.

Google Earth image of the general area in which USS Robalo is assumed to have been lost

In her first patrol, in the area west of the Philippines, ROBALO damaged a large enemy freighter. Her second patrol was in the South China Sea near Indo-China; here she sank a 7500-ton tanker.