1.513 Golygfeydd
In the second of this two-part series, David Hayman explores Germany's World War One U-boat threat and the fascinating and dastardly ploys Britain used against the submarines.
Dyddiad Awyr Cyntaf : Apr 07, 2015
Dyddiad Awyr Olaf : Apr 14, 2015
Pennod : 2 Pennod
Tymor : 1 Tymor
Amser Cinio: 60:14 munudau
Stiwdio: BBC Two
Gwlad: Germany, United Kingdom
Cast: David Hayman