Siegfried von Forstner Korvettenkapitän Siegfried Freiherr von Forstner ( 19 September 1910 – 13 October 1943 ) was a German U - boat commander during World War II . He was also a recipient of the Knight ' s Cross of the Iron Cross ( ) . The Knight ' s Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership . He and his entire crew of were killed in action on 13 October 1943 . Background . Von Forstner was the son of an aristocratic Prussian family whose men had served for generations as Army and Navy officers . His younger brother Wolfgang Friedrich ( * 1916 ) was also a U - boat commander , and two other brothers ( Ernst Richard and Hans Dietrich ) were Army officers . Wolfgang was the only brother to survive World War II . Their great - grandfather and grandfather had been army officers , and their father was a general , Ernst Freiherr von Forstner ( 1869 – 1950 ) , who had won the Pour le Mérite with cluster as a regimental commander during World War I . Their uncle George Gunther von Forstner had commanded and during World War I , and another uncle of the Imperial Navy had died in that conflict . Career . Siegfried von Forster joined the Kriegsmarine in 1930 and served four years on the following training as an artillery technical officer . Many of his year group were already at sea in submarines when he entered U - boat school in 1940 . Von Forstner received training as a student commander aboard under his Naval School classmate Otto Kretschmer . After a 5 - month tour in , von Forstner assumed command of . Von Forstner carried out eight combat patrols in " U - 402 " sinking 14 merchantmen and one warship and damaging three other ships . Von Forstner married in Hamburg in December , 1940 , while waiting to take command of " U - 402 " . His wife Annamaria made distinctive red pom - pom s for the crew of " U - 402 " to wear on their uniform hats . The Baron and Baroness saved their home in Hamburg from burning during August , 1943 , air - raids by staying on the roof and extinguishing incendiary bomb s . No ships were sunk during the first " U - 402 " patrol from 26 October 1941 to 9 December 1941 . On the second patrol von Forstner damaged the 12000 - ton troopship off the Bay of Biscay on 16 January 1942 but the damaged troopship was able to make repairs in the Azores . Von Forstner then made two patrols off the Atlantic coast of the United States . He sank a 4800 - ton ship en route and then sank the 5300 - ton Russian tanker " Ashkabad " and the 1000 - ton converted yacht USS Cythera ( PY - 26 ) off Cape Hatteras on 2 May 1942 . On the next patrol , " U - 402 " was depth charged by patrol bombers off Cape Hatteras in mid - July and suffered a battery explosion . Von Forstner received the Knight ' s Cross of the Iron Cross for torpedoing twelve ships from convoy SC 107 and convoy SC 118 . Baron von Forstner sank two ships during a submerged daylight attack on convoy SC 129 before " U - 402 " was depth charged and damaged by the corvette " Gentian " . Baron von Forstner shot down an attacking RAF 172 Squadron Vickers Wellington bomber over the Bay of Biscay following departure for his last patrol on 4 September 1943 . " U - 402 " provided flak protection for when the latter was attacked by a B - 24 Liberator bomber during the battle of Convoy ON 202 . A U - boat believed by the Allied Anti - Submarine Assessment Committee to be " U - 402 " was sunk with all hands on 13 October 1943 by a Mark 24 FIDO Torpedo dropped by TBF Avenger aircraft from USS Card ( CVE - 11 ) . Summary of career . Ships attacked . As a U - boat commander of Siegfried von Forstner is credited with the sinking of 14 ships for a total of , further damaging three ships of and sinking one auxiliary warship of .