their tactics placed first emphasis on self-preservation rather 

 than on aggressive action against Allied shipping., U-boat com- 

 manders took to hunting for soft spots „ 



July saw the invasion of Sicily carried out with no losses 

 from U-boats, During August 1943, 25 U-boats were sunk, 5 being 

 sunk by planes from one American escort carrier the US3 CARDo 

 It was estimated that the energetic countermeasures of the 

 Allies were driving the U-boats to their home ports an average 

 of 2 weeks earlier then normal „ 



The 3-ermans came up with two new weapons „ In the Bay of 

 Biscay the Allies had pushed their escort groups as far as 

 possible. This resulted in a violent German reaction through 

 the use of a new jet-propelled radio-controlled glider bomb 

 which sank one British warship and damaged two others. The 

 Germans emerged with a second new weapon in the acoustic 

 homing torpedo, the T-4 and later the T-5, which would track 

 the noise of a ship against which it was fired. How Division 

 6 of IIDRC helped defeat the homing torpedo is described else- 

 where in thi s volume „ 



Allied countermeasures mere than made up for these German 

 innovations , 



February 1944 was notable for the 27-day patrol of the 

 Second Escort Group in which every one of six submarines con- 

 tacted was hunted to destruction. The new sonar apparatus 

 which had been developed was being used with telling effects. 

 The apparatus provided not only the range and direction of an 

 enemy U-boat, but also its depth, and enabled attacking 

 vessels to maintain contact at very close range. The new ap- 

 paratus made it possible for depth charges to be set for 

 detonation much more accurately than hitherto. 



In March 1944 in the Pacific, American antisubmarine 

 vessels scored multiple successes. Perhaps outstanding in 

 achievement was the USS ENGLAND which sank 5 Japanese sub- 

 marines and took a major part in the sinking of a sixth. 



The increased safety of Allied convoys derived in no 

 small part from the painstaking analysis of convoy and anti- 

 submarine operations,, In this analysis, the scientists of 

 IIDRC both in Division 6 and in the Operations Research Group 

 played an important part, A study of attacks on shipping by 

 U-boats and their results indicated that the safety cf inde- 

 pendent ships depended very much on the speed of the ship. 



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