U-boats in the Atlantic during this critical phase of the 

 war were safer than at any other tirae Of the average of 57 

 submarines at sea, four and a half were sunk per month so that 

 the U-boat's average life attained a high of 13 months, during 

 which it could be expected to sink 19 ships totaling 100,000 

 gross tens. 



The U-boats achieved these successes by concentrating 

 their raids in the United States Strategical Area, where, at 

 that stage of the war, the defenses were weak and shipping 

 unescortedo In the area, the Germans maintained 37 out of 

 the average -of 57 U-boats at sea, and these 37 submarines 

 sank an average of 75 ships of 375,000 gross tons per month 

 at a loss to themselves of only 2 1/3 U-boats per month. By 

 September 194 2, the Germans were able to maintain as high as 

 93 U-boats at sea in the Atlantic at any one time. In addi- 

 tion, they were able to maintain an average of 20 U-boats in 

 the Mediterranean and another 20 were available for operation 

 in the Barents Sea. Japan had approximately 75 submarines 

 available and operating in the Pacific and Indian Oceans. 



So serious were the losses in the U. So Strategical 

 Area, that in March the United States was forced to convoy 

 shipping along the East Coast „ This coastal convoy system 

 required the marshalling of all our available forces. The 

 Navy assigned to the job every available plane and blimp, 

 and was lent assistance by first one and then a second Army 

 air unit. In order to conserve anti-submarine forces, all 

 forces of this type, of the United States, Britain and Canada, 

 were consolidated into a single transatlantic convoy escort 

 system. 



During hay, the situation in the Gulf Sea Frontier became 

 particularly serious. The average number of U-boats in that 

 area was estimated at only 4, but during the month they sank 

 41 vessels of 220,000 tons - probably an nil time high for 

 sinkings by U-boats in any area during any period of the war. 

 At the rate of sinkings prevailing in the Gulf during Kay, 

 the life expectancy of a merchant vessel at sea in that area 

 was only 2 months. 



The increased number of U-boats available to the Germans 

 was beginning tc tell. By August, 1942, while still contin- 

 uing their attacks in the U. S. Strategical Area, the Germans 

 were able to resume raids in the North Atlantic. 



- 71 



