2/3的U艇被盟軍擊沉

U-96 was a Type VIIC U-boat of the German Kriegsmarine during World War II. Her keel was laid down September 16, 1939 by Germaniawerft, of Kiel. She was commissioned September 14, 1940 with Kapitänleutnant Heinrich Lehmann-Willenbrock in command. Lehmann-Willenbrock was relieved in March 1942 by Oberleutnant zur See Hans-Jürgen Hellriegel. He was relieved in turn in March 1943 by Oblt. Wilhelm Peters. In February 1944 Oblt. Horst Willner took command, turning the boat over to Oblt. Robert Rix in June of that year. Rix commanded the boat until February 1945.

As part of the 7th Flotilla, stationed in Saint Nazaire, France, U-96 conducted 11 patrols, sinking 28 ships totalling 190,094 tons and damaging four others totalling 33,043 tons. On March 30, 1945, U-96 was sunk by US bombs while in the submarine pens in Wilhelmshaven. In her entire career, U-96 suffered no casualties to her crew. The boat was also known for its emblem, a green laughing sawfish. The laughing sawfish became the symbol of the 9th Flotilla after Lehmann-Willenbrock took command in March 1942.

During 1941, a war correspondent named Lothar-Günther Buchheim joined U-96 for a single patrol. His orders were to photograph and describe the U-boat in action for propaganda purposes. From his experiences, he wrote a short story, "Die Eichenlaubfahrt" ("The Oak-Leaves Patrol") and a 1975 novel which was to become an international best-seller, Das Boot, followed in 1976 by U-Boot-krieg ("U-Boat War"), a nonfiction chronicle of the voyage. In 1981 Wolfgang Petersen brought the novel to the big screen with the most expensive German film to that date, Das Boot, critically acclaimed by many as one of the best submarine films of all time。

以上來自wiki
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鄧尼茨從一開始就知道與英美海軍正面作戰完全沒有勝算，因此，他只能柿子撿軟的捏，制定了非常明確的戰術，拿商船隊開刀！並且，在攻擊時，也是首選打擊貨船油船，不主動進攻護航的軍艦，儘可能以全部力量摧毀盟軍的補給力量。這點在影片中得以完全貫徹。
但是，縱然潛艇官兵英勇善戰，也阻擋不了戰爭物資源源不斷地輸送到歐陸戰場。按鄧尼茨的說法，德國潛艇擊沉盟軍商船的速度（總共2,880艘，平均噸位約5,000噸），遠趕不上盟國造船的速度（美國光7,000噸的「自由」級貨船，就造了2,700艘！各種原因沉沒的只有300來艘），嗚呼哀哉！而德國潛艇，一共建造了逾1,000艘（影片中的U-VII型是主力，造了700來艘），被擊沉了630多艘。
二戰期間，美國製造了18,000餘架B-24轟炸機，其中很大一部份用於大西洋反潛作戰。面對如此強大的對手，U艇實在勉為其難。但影片對美軍的空中反潛行動著墨很少，不知是何原因。