- n (esp in World War II) Germansubmarine （尤指第二次世界大戰中的）德國潛艇
- Enigma adapted from british author robert harris's best-selling novel tells the tale of bletchley park britain's top-secret code-breaking unit set up to smash the famous enigma cypher used by the german u-boats.
- Asdic reports lost contact with u-boat.request another sweep.
- The small ship came around the headland and steamed toward the u-boat.
- Bloody u-boat! Must have sunken.
- The u-boat could keep the sea for three months.
- In order to get skilled u-boat men back into the war.
- He's got more authority here than he ever had on a u-boat.
- A british destroyer reported depth charging and sinking a german u-boat.
- There's a u-boat coming to pick them up.