Though he entered combat late in May 1942, Carl Emmermann sank twenty-six Allied ships in only four combat patrols while commanding U-172, becoming the thirteenth most successful U-boat commander of the war. U-172, a Type IXC U-boat, saw non-stop action throughout the Atlantic, during its four patrols under Emmermann. U-172's third patrol to Cape Town would be its longest with 131 days at sea, where it added eight vessels to its list of successes in this sector; the first sinkings in this area for the U-boat service. On its sixth patrol under a different commander, U-172 would later be sunk in December 1943. Awarded the Knight's Cross with Oak Leaves in 1944, Emmermann was ordered at St. Nazaire, France, to command the Kriegsmarine's 6th U-boat Flotilla. Later in Germany, he became the new sub-specialist for the Type XXIII U-boat, and in the last months of the war, commanded a marine battalion in defense of Hamburg. This biography details all WWII patrols by U-172 and features over 230 images and maps.