From the beginning of WWI to the US entry in 1917, it was Ireland who played the major role in saving the British supply lines from total strangulation by German submarines. Cobh, in particular, played a crucial and largely forgotten role in the battle for the Atlantic. It was from its secure harbor that British and American naval forces battled the German empire's submarines and navy. This new and comprehensive study of the role Cobh played, looks at the circumstances that surrounded the feat and at the interesting characters that commanded the navies and crewed the ships.