On 23 June 1942, PCU POGY (SS-266) splashed sideways into the waters of the Manitowoc River; she was commissioned six months later and dispatched to Pearl Harbor. As she set off on her fourth war patrol on 25 November 1943, the crew must have been feeling pretty good: over the course of their first three patrols, they had sunk two freighters, a gunboat, a sampan, an aircraft ferry, and a submarine tender; she also damaged several other ships but could not confirm that she had sent them to the bottom. But an encounter on 13 December was a vivid reminder that her opponents should not be underestimated.

At 0530 in the morning, POGY sighted two freighters and an escort clearing the harbor of Palau, a tiny island nation five hundred miles east of the Philippines. At 0700, she fired three torpedoes at the Panama Maru, a troop transport. “Saw first one hit under the bridge and ship sag in the middle,” POGY’s commanding officer wrote in the patrol report. “Heard second hit seven seconds later as we were going deep. Heard target breaking up and sinking for next hour.” At 0747, the escort “dropped [the] first two of 27 depth charges,” but the sub remained unharmed. When she came to the surface at 0914, there were no ships in view, but 33 minutes later smoke was sighted. The commanding officer ordered a course change, “hoping to get a shot at the second ship if he started out again, or at least trail him and be in favorable position for a night attack.”

But nothing happened for the remainder of the morning. Then, at 1330, POGY’s crew heard “two distant depth charges. Shortly afterward, two PC type patrols came in view, both pinging, running at slow speed, and crisscrossing the area. …Kept stern to whichever patrol seemed closest.” Four hours later, a “patrol came up from astern, much closer than any had been previously. He was very cagy—he apparently (hind sight) picked us up at about 6,000 yards but kept easing in at slow speed to about 3,000, giving us big angles on the bow in each direction while so doing.” POGY’s crew had been tricked, although that fact did not become evident until 1806 when the patrol boat “headed right for us and poured on the coal. Started deep and rigged for depth charge attack, but too late. He let go with a pattern of three [depth charges] that caught us as we passed 150 feet. One was very close on the starboard side, about amidships. …The next half hour was a very bad one. He dropped no more charges, and we were at 290 feet under a density layer, but he was pinging on us and we could hear the echoes bouncing back even if he couldn’t.” POGY made her way up to periscope depth at about 1830. “Picked up patrol on radar 6000 yards astern. Cleared area to eastward on 4 engines. Lost radar contact at 8600 yards.” Given the damage she had sustained, POGY’s commanding officer elected to return to port for repairs.

In his post-patrol evaluation of the encounter, the C.O. wrote, “I believe that after our attack…, a number of patrol craft conducted a systematic search of the entire area, probably using some form of retiring search curve, that resulted in our being located again. The patrol which depth charged us late in the afternoon missed a golden opportunity when he stuck to continuous echo ranging after his attack. The noise we made blowing out 12,000 pounds, to enable us to come to the surface, must have been audible for miles.”

POGY would go on to complete a total of ten war patrols, sinking 16 ships (total tonnage—62,633) and receiving eight battle stars. It is doubtful, however, that the crewmen who survived the 13 December attack ever took their success for granted. Had the density change not existed or the patrol boat remained on station—or been more precise in her depth charging—the story would have ended very differently.