Now in its final resting place at the bottom of the Potomac River in Maryland, the U-Boat U-1105 is unique among German World War II submarines. Technologically innovative, it was the only U-Boat to conduct a wartime patrol while equipped with the snorkel, GHG Balkon passive sonar and a rubberized coating known as Alberich designed to reduce its acoustic signature and hide from Allied sonar. After the end of World War II, it was the subject of intense testing and evaluation by the Allies, before finally being sunk to the bottom of the Potomac River. This highly illustrated book uses many new and previously unpublished images to tell the full story of this remarkable U-Boat, evaluating the effectiveness of its late war technologies, document its extensive postwar testing and detail all the features still present on the wreck site today.