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The Eastern Sea Frontier
During WWII the waters from Canada to Jacksonville, Florida were monitored by a Naval Division known as the Eastern Sea Frontier with offices in New York City. A “War Diary” was written monthly discussing all activity in this area by the Germans and the Allies. The following is an excerpt from the “War Diary” during April 1942.
...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 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 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