CHAPTER II 



SUBMARINE DETECTION PRIOR TO 1940 



The Kaiser's admirals, at the outbreak of World War I, 

 had in their submarines a better weapon than they realized, 

 and one which an unprepared Allied technology was not ready 

 to combat „ 



The U-boat successes of World War I are material to the 

 story of sub-surface warfare during World War II because they 

 set in train a scientific program to devise countermeasures, 

 and because -- as has proved true in other fields of military 

 unpreparedness -- the counter-measures which resulted came too 

 late to play a major role in the war which generated them, but 

 were to be the basis for the technical equipment of World 

 War II . 



Subsurf ace Warfare in World War 1, 



Though the Germans were able to keep at sea at any one 

 time during 1915 and 1916 „ an average of only some 15 U-boats, 

 their submarine s, thanks in part to the British refusal to 

 adopt the convoy system, sank an average of approximately 

 200,000 gross tons of Allied shipping per month,, 



Losses of U-boats averaged only l|- vessels per month,, 

 Thus, the life of a U-boat approximated ten months, during 

 which it might be expected to sink 130 s 000 gross tons of ship- 

 ping — a fair bargain of war from the Germans' viewpoint and 

 one which led them, in February, 1917, to commence a campaign 

 of unrestricted submarine warfare,, 



Allied shipping losses from submarines rose steadily until, 

 in April, 1917, they reached a peak of 440 ships totaling ap- 

 proximately 900,000 gross tons. This crisis, plus the insistent 

 advice of Americans Sims and Britain's Jellicoe, finally impelled 

 the adoption of the convoy system 



But convoying, while it cut shipping losses, did not defeat 

 the U-boat „ From early in 1917 until the close of the war, the 



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