The Destroyer Escort Program

    From the shores of the east coast we watched as our merchant ships were torpedoed by U-Boats on the surface, firing without fear of attack. Off the coast the wrecks accumulated. Shipwreck debris and dead crewmembers washed up onto our shores...and there was little we could do.
    In June 1942 the British ordered 50 destroyer escorts from American shipyards under the lend-lease act and by late 1942 the building was fully underway at 17 shipyards across the United States. By the end of 1942, 31 DEs had been delivered.  It was a simple matter to siphon off some of the British-intended DEs and put them into U.S. service, and that is exactly what we did, not only with DEs but with aircraft, vehicles, and other armament. Soon a flood of war materiel was flooding into the logistics system.  By the end of 1943, another 378 DEs had been delivered, 78 of which went to the British under the lend-lease agreement.

    In early 1944 the U.S. Navy canceled many of the orders of DEs which had been completed. Only 563 destroyer escorts were completed. Some of the remaining keels which had been laid were completed as other type ships such as High Speed Transports (APD) and Radar Picket Ships (DER).

    At the end of World War II, most of the destroyer escorts were decommissioned and placed in moth balls. With the destruction of the U-Boat threat, the DE's short life was nearing an end...but not quite.  With  technological developments in jet engines and high-speed attack aircraft, the DE had another lease on life, the radar picket ship, known as the DER conversion. In addition, the Navy needed and shallow-draft vessel for fast attack troop transports, which the DE accommodated perfectly with the APD conversion. Finally, with simple systems and reliable power plants, the DEs were ideal in the role of naval reserve training ships, with 27 remaining in service until the 1950s. During the Korean war the number of DEs in commission was increased to 52 as the Coast Guard activated mothballed ships. In 1960 only three destroyer escorts served with fleet units. Another 28 DEs trained reservists. Mass scrapping of ships remaining in reserve began five years later. The last World War II-built DEs were stricken in 1973, leaving only DERs on the Navy list. 

   Paukenschlag - Operation Drumbeat

Kptlt. Reinhard Hardegen after a successful patrol with his U-123

U-125 was the first to sail on 18 December 1941, followed by U-123 (Hardegen) on the 23rd and U-66 on the 24th, finally the last two of the Paukenschlag boats, U-130 and U-109 sailed together on the 27th. It took just over 2 weeks to reach US waters. They were under strict orders not to attack anything on the outbound cruise unless a especially attractive target was located (this meant a big warship like a cruiser, carrier or a battleship, but like Doenitz said "We never let a 10,000 tonner pass us by").
    All the boats were to be in position on Jan 13 and begin their attacks at the same time on that date. However, U-123 sank the SS Cyclops on the 11th and U-130 sank two ships over the next two days.  After that, they sunk at least one per day as  far south as the Cape Hatteras.
    The Drumbeat boats ended operations of the coast of America on Feb 6 and headed home. They sank 25 ships for a total of 156,939tons. U-123 sank 9 ships for a total of 53,173 tons.
    Operation Drumbeat was just the initial wave of U-boats, Paukenschlag was meant to be a fast and surprise attack on the eastern seaboard of the US, and it succeeded as such. Then there were several other "waves" of U-boats that went into American waters but didn't count as "Drumbeaters".
    By the time the Paukenschlag were returning to their French bases in February the next wave of boats had already hit. In the following waves came many of Germany's most experienced commanders. 

A type VII boat returning to port.

    In order to make the journey, even with the Milkcow support, some of the smaller VII boats had to sacrifice a large portion of their drinking water and put diesel fuel in the tanks instead.

Refueling from the Milkcows
During early May the Milkcow U-459 refueled 15 U-boats northwest of Bermuda and thus greatly extended the range and patrol time of the U-Boats. This also gave Admiral Doenitz the option of attacking much further south than previously possible.

Gulf of Mexico
U-507 sank the first ship in the Gulf of Mexico on May 4, 1942 when he torpedoed the 2,686 ton freighter Norlindo west-northwest of Key West. During the rest of May a ship would be lost roughly every day. The last ship to be sunk in the Gulf went down on 4 September 1942.

The Caribbean
Convoy systems were started in the Caribbean in July. This convoy system was more complex than the one established on the US seaboard but it still required the assistance of British and Canadian corvettes. 20 ships were sunk in the waters of Panama. 

Convoy system started
In middle of May 1942 the US finally started running convoys on the East coast, over 4 months too late. They proved to be effective right from the start like the British had known for more than 2 years at that time and had told the US Navy command again and again.

On 19 July 1942 Grand Admiral Doenitz withdrew the last two boats operating of Cape Hatteras, U-754 and U-458, and 8 days later he shifted the effort back into the North Atlantic where it had all began and would eventually end.

Statistics
    During the first 6 months of the German U-boat offensive out of the US east coast some 397 ships totaling over 2 million tons were sunk, costing roughly 5,000 lives. In the process only 7 U-boats (U-85, U-352, U-157, U-158, U-701, U-153 and U-576) were lost. There were only survivors from U-352 (15) and U-701, the rest went down with all hands. 302 Germans were lost on these 7 boats.