The first U-boat sunk in 1943 was U-164, the end came quickly and apparently completely unexpectedly. On January 6, 1943 while returning from convoy escort duty Lieutenant (j.g.) William R. Ford, USNR in a PBY-5A of VP-83 based at Natal, Brazil, located the submarine on the surface. At the time of contact Ford was at about 5,500 feet, he immediately turned to port and powered back his engines until he was almost gliding. Making a very quite approach and keeping in the clouds worked very well for the daylight attack, according to Ford the U-boat did not appear to sight him as no evasive action was taken.

He got to within four miles of the boat before he throttled the engines back up and began final approach. He flew over the boat at about 35 feet and released four depth bombs, three of which exploded alongside the boat. The boat came up almost out of the water and appeared to break in half and submerge.

One of the crewmen of the PBY noticed three large cylindrical tanks rise to the surface along with other debris and bodies, he also observed three survivors in the water. The tanks were fired on with the .50 machine gun and one of the survivors appeared to have been killed instantly. The other two were waving with one hand and trying to keep afloat with the other.

Circling the area a liferaft was dropped, but the men in the water could not reach it. A second raft was dropped close enough that one man swam to it and then rowed it to the other man who was clinging to one of the tanks. The plane continued to circle the survivors and prepared to drop lifejackets that had water casks inside them, but contact was lost due to the rough seas. They searched for three hours for the two men, but were unable to locate them. A rescue ship was sent out with no results, it was thought that all hands were lost.

Seven days later the two survivors came ashore near Cururupu, Brazil over 400 miles west of where their boat was sunk. They were taken into custody by the local police and later turned over to the U.S. Navy. It was learned that they were the only two who survived the attack, this was only because they had been on the casing when U-164 submerged and were trapped outside after the hatch was closed. Fortunately for them they had been outside washing up just before the attack. They also denied that any bodies had been in the water and confirmed that they were the only two survivors (the third man, supposedly killed by gunfire, must have been some debris).

U-164 had only been on two war patrols sinking only three ships, five Allied seaman were lost in the ships. The German U-boat lost ten times as many men plus four, fifty-four men were lost in the boat. Lieutenant (j.g.) Ford would sink U-598 on July 23, 1943 and be awarded the Distinguished Flying Cross. Locating the U-164 in such rough seas must have been quite a feat. Was it luck to see such a small object tossing around from 5,500 feet or were they directed to the location via an Enigma decrypt, not having access to those documents I can not say for sure.