The third war patrol of the USS Piper (SS-409), under the captaincy of Lieutenant Commander Edward L. Beach, was conducted in the Sea of Japan during the period covering July 19, 1945 to September 9, 1945. Twenty-one days were spent in the assigned area, with only one day in the area prior to the cessation of hostilities. On August 11, 1945, the Piper was in the Yellow Sea where she destroyed two five-ton fishing boats with gunfire. One was seen to sink and the other was left in a sinking condition. On August 14, 1945, a deserted one hundred-ton combination fishing boat and landing craft was seen. Two thermite grenades were tossed aboard it and the Piper proceeded on her patrol. The Piper was equipped with the latest mine detection sonar. She entered and exited the Sea of Japan via the Tsushima Strait.
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