(Fisher. (London 1919), brief 2 van 9 en 10 september 1914, Foreseeing the submarine, p.173-188).
Unrestricted Submarine War
‘The submarine is the coming type of war for seafighting’ en ‘Again the question arises as to what a submarine can do against a merchantship when she has found her. She can not capture the merchant ship; she has no spare hands to put a prize crew on board…Under these circumstances, it is presumed that the hostile submarine will discard such law and sink any vessel heading for a British commercial port and certainly those that are armed or carrying contraband? There is nothing else the submarine can do except sink her capture and it must therefore be admitted that (provided it is done and however how inhuman and barbarous it may appear) this submarine menace is a truly terrible one for British commerce and Great Britain a like, for no means can be suggested at present of meeting it except by reprisals. All that would be known would be that a certain ship and her crew had disappeared, or some of her boats would be picked up with a few survivors to tell the tale…but again if it is done by the Germans the only thing would be to make reprisals. The essence of war is violence, and moderation in war is imbecility’.