The USS Capelin (SS-289), a Balao-class submarine, represented the cutting edge of U.S. naval engineering during World War II. Constructed at the Portsmouth Naval Shipyard in Kittery, Maine, she was launched on March 20, 1943, and commissioned on June 4, 1943, under the command of Lieutenant Commander Elliot E. Marshall. Despite a promising start, the Capelin vanished during her second war patrol, becoming one of the enduring mysteries of World War II. Declared overdue and presumed lost on December 2, 1943, the circumstances of her disappearance remain speculative, leaving her story as a haunting reminder of the sacrifices made by submariners.