The USS Perch (SS-176) was a Porpoise (SS-172)-class submarine commissioned on 19 November 1936. In 1939, the Perch sailed for the Philippines and became a division flagship. In the summer of 1940, she sailed to Tsingtao and Shanghai, China. She continued operations around the Philippines, and during the final week before the United States entered World War II, the Perch escorted the 4th Marines from China to the Philippines. After carefully sailing through the minefields around Corregidor, the Perch looked for targets between Luzon and Formosa and later off Hong Kong.
On 25 December 1941, the Perch sighted a convoy. She fired four torpedoes at a 4,000-ton freighter, but they all missed. The following day, two more torpedoes were fired in a submerged attack; again the torpedoes missed their intended targets. Finally on the 27th, the Perch attacked an 8,000-ton Japanese merchantman and reportedly sank the vessel, although she immediately took evasive action and was unable to observe or confirm the kill.