USS Grayling (SS-209) was a Tambor-class submarine of the United States Navy, commissioned on 1 March 1941. Built at Portsmouth Navy Yard in Kittery, Maine, her keel was laid down on 15 December 1939, and she was launched on 4 September 1940. Grayling was a significant early-war vessel, measuring approximately 311 feet in length with a beam of about 27 feet, designed for stealth and extended underwater endurance typical of Tambor-class submarines. Her service began with Atlantic Fleet operations before transferring to the Pacific, arriving in Pearl Harbor in December 1941. Grayling played a prominent role in the early naval battles of World War II, including being chosen to hoist Admiral Chester Nimitz’s flag during the Pacific Fleet change of command on 31 December 1941. Her first war patrol commenced on 5 January 1942, cruising near the Northern Gilbert Islands, though without success. Her second patrol was more fruitful, sinking the cargo ship Ryujin Maru off Japan on 13 April 1942. Grayling participated in reconnaissance operations during the Battle of Midway and was targeted mistakenly by American B-17 bombers in June 1942, narrowly avoiding damage. She continued her patrols around Truk and the Philippines, sinking multiple Japanese vessels including the cargo ship Ushio Maru and Shanghai Maru. Notably, during her sixth patrol, she sank Shanghai Maru on 9 April 1943, and on her seventh, she damaged several ships off northwest Borneo. Her eighth and final patrol began in July 1943. During this mission, she supplied guerrillas in the Philippines and recorded her last kill, the Meizan Maru, on 27 August 1943. Grayling was lost sometime between 9 and 12 September 1943, after reporting no contact following her last known activities. Japanese sightings of a submarine in her patrol area suggest she was either sunk operationally or by an unrecorded attack. She was credited with sinking over 20,000 tons of Japanese shipping and earned six battle stars, marking her as a notable and successful wartime vessel. Her loss remains an unresolved maritime mystery.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.