Germany changed the tactic during WWI via unrestricted submarine warfare ... that the world's navies feared German U-boats. In 1914, Germany began producing Type U 19 submarines (pictured ...

The U-boats' 15-knot surface speed was almost twice that of an average convoy and equal to that of most anti-submarine escorts. A German band welcomes a Type VIIC U-boat, the mainstay of the ...

The following images, provided by Tyne & Wear Archives, show the heart of a World War I German submarine that sank in 1918 after it was rammed by a torpedo boat destroyer. During WWII, Germany ...