EASTERN SEA FRONTIER
WAR DIARY
APRIL 1942
  
     
 
CHAPTER I
  
 
 
 
THE SUBMARINE SITUATION
  
     
 
        In the submarine warfare, April was almost an exact repetition of the preceding month. Twenty-four vessels, a total of 138,121 tons, were sunk in the last thirty days. Thus, once again, the Eastern Sea Frontier was the most dangerous area for merchant shipping in the entire world. Of the seventy-three ships sunk by enemy submarine action in April, 33% went down in the Frontier. Seventeen, or 23% of the world total, were lost in the Mid-Atlantic area, the second largest theatre of U-boat activity. The remaining thirty-two sinkings were scattered fairly evenly over the face of the oceans.
  
     
          The pattern and rhythm of attack was likewise much the same as in the preceding month. Thirteen sinkings, concentrated in the first ten days, were followed by two weeks of reduced activity on the part of the Germans. But by the end of the month the tempo of loss was rising again. It seems reasonable to infer from this that during the middle of April the replacement process noticed in the March diary was again taking place during the period in which the comparative lull occurred.  
     
          No great change in the methods of attack took place. Submarines still preferred to operate ordinarily at night and they frequently supplemented torpedoes with gunfire. The favorite field of activity remained Hatteras, though toward the end of the month it was apparent that a slow shift to the south was taking place. This too conformed to the trend  
 
 
 
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observed in previous months. From the very beginning of the submarine war off Montauk in January, a gradual movement down the coast has been discernable. The exact number of U-boats operating at any one time has proved very difficult to calculate, but a reasonable estimate would seem to be between five and eight within the Frontier.
  
     
 
        From the beginning of the war there has been a belief that enemy agents or sympathizers have been assisting U-boats in their campaigns. Such assistance could have many forms--fueling the submarines from isolated places along the coast, radioing information about ship departures, meeting them at sea in small boats filled with oil and provisions. There have also been rumors about neutral vessels or German supply ships that lie off the coast to tend the submarines. Thus far it has been difficult if not impossible to obtain conformation for these reasonable beliefs.
  
 

 

  
 
        But this month strong circumstantial evidence was provided through an analysis of submarines movements. In the third week of January, five U-boats passed Bermuda headed in the direction of the Florida Straits. During the next two weeks there were a number of reports received of sightings of enemy submarines off the Florida Coast and the Gulf of Mexico, but there were no attacks made in these areas until February 16th when several were made by a number of the enemy near Aruba. In the following two days the submarines were active around Martinique and Trinidad.
  
     
          It is a fair conclusion that these attacks were carried out by the submarines known to have passed Bermuda, since no U-boats were  
 
 
 
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located on courses leading to the Caribbean during the first part of February. If this conclusion is correct it suggests that these submarines were fueled and their crews rested somewhere in the Western Caribbean.
  
     
 
        This pattern has recently been repeated. In the last week of March, six U-boats entered the Caribbean from the northeast but during the first weeks of April no attacks were reported from the Caribbean area. Ten days after their arrival was known, three of the submarines appeared off the Florida and Georgia Coast. It seems again a fair conclusion that these enemy units came from the Caribbean after a period of rest and reprovisioning.
 
 

 

  
 
        Pont is given to this belief by known capabilities of the common, 740-ton, German undersea boat. The voyage from the Bay of Biscay to Hatteras takes about seventeen days. This means that a submarine can remain in these waters only about nine days before returning. If it elects the round about route through the Caribbean and up to Florida or Georgia, the operational days are reduced from nine to five. Five active days out of a cruise of forty-three days would appear uneconomic if some means of extending the active days were at hand. Such increase in operating time could obviously be obtained if crews could be rested and ships refueled on this side of the water.
  
     
 

        After studying this information, Commander Eastern Sea Frontier reached the conclusion that submarines were quite possibly making rendezvous with tankers flying neutral flags and operating out of Colombia, Venezuela, or Mexico. It was equally possible that they were using some

  
 
 
 
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small island, such as Corn Island off Nicaragua, as a base. For this reason he recommended on April 24th that a thorough search be made of all small tankers and freighters in the area and of the small islands off Nicaragua and Honduras.
  
     
 
        During the past month the most disturbing single factor about the submarine warfare has been the fact that it has been maintained with such success. This success can be traced to several factors but the most important is the fact that it is impossible to combat the menace with forces of inadequate strength. The outlook for May is still almost as disturbing as it was at the beginning of April, though pessimism should be tempered somewhat by the recognition that ships and planes are gradually accumulating along this coast and a protective system of considerable strength has been devised for the merchant vessels in our coastal waters.
  
 

 

  
 
 
     
 

 

  
 
 
 
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