uboat.net - Fighting the U-boats (2024)

Only five ships had been sunk in the Gulf Sea Frontier in the first fourmonths of 1942, but in May 1942, submarines sank 41 ships, totaling 219,867gross tons, with 55 percent tanker tonnage. By July 1942, the enemy hadsunk 62 ships in the Gulf of Mexico. As many as four enemy submarines at atime prowled the Gulf of Mexico between May and August 1942, takingadvantage of skimpy air patrols and the lack of a convoy system.

The shift of the German submarine offensive to the Gulf overwhelmed theresources of the U.S. Navy and the USAAF, which were barely adequate todefend against submarines in the Eastern Sea Frontier. The U.S. Navy hadcreated the Gulf Sea Frontier in February 1942 with minimal surface and airforces, and the USAAF had contributed only 14 observation aircraft and twoworn out B-18's. To counter increased submarine attacks, the USAAF, between8 and 10 May, sent a squadron of light bombers (A-29's) to Jacksonville, Florida, and sixmedium bombers (B-25's) to Miami, Florida and on 20-21 May sent adetachment of B-25's to Havana, Cuba, to patrol the Yucatan Channel.

Admiral Doenitz

On 26 May, the 1st Air Force created the Gulf Task Force and stationed it atMiami. This organization, which continued to operate until November 1942,cooperated with the Commander, Gulf Sea Frontier, to provide operationalcontrol of all USAAF aircraft that flew anti submarine patrols in the area.At the end of July 1942 the U.S. Navy instituted a convoy system in theGulf of Mexico, and German submarines faced the same dangers they had offthe East Coast. On 4 September 1942, the United States lost the last shipsunk by enemy action in the Gulf of Mexico, as Admiral Doenitz withdrew all submarines from the Gulf.

The devastation of German submarine attacks in the Caribbean Sea Frontiermatched that in the Gulf Sea Frontier. Having dispatched a sizeable forceto the U.S. East Coast, Admiral Doenitz fixed the opening of the Caribbeanoperation for the new moon period of February 1942. On 16 February, aGerman submarine sank two tankers off San Nicholas, Aruba, then moved intothe harbor and shelled a refinery, inflicting little damage but killingfour people. In February and March, the Germans operated six submarines inthe Caribbean Sea, each patrolling for two to three weeks before returningto France. Then, in April, a second wave of submarines arrived in the area;some, refueled and replenished northeast of Bermuda by "milch cow"submarines, stayed up to six weeks. By July, the German submarines had sunksome 141 ships and sank another 173 ships in the Caribbean Sea Frontier andits approaches by September. Between February and September, the Germansubmarines sank an average of 1.5 ships each day, destroying over onemillion gross tons in the Caribbean and adjacent waters.

U.S. military leaders had been aware of possible threats in the Caribbeanand the Gulf of Mexico at the beginning of the war. The USAAF, fearing anattack on the Panama Canal, in December 1941 transferred to the Canal Zone80 additional fighter aircraft, nine heavy bombers, and four mobile radarsets. In February 1942, the 6th Air Force assumed responsibility for theaerial defense of the Panama Canal. Major General Davenport Johnson,Commander General 6th Air Force, concentrated aerial patrols on the Pacificside in fear of a carrier borne Japanese attack. Then in April 1942, whenthe German submarine threat became evident, the 6th Air Force, cooperatingwith the U.S. Navy, instituted anti submarine patrol flights as far east asCuracao. Most flights were by tactical aircraft, such as Bell P-39Airacobra’s and Northrup A17's, which could fly only during daylight;lacking radar and trained observers, the pilots had little luck in spottingenemy submarines. On the other hand, 6th Air Force aircraft occasionallyattacked friendly ships and submarines, fortunately without damaging them.

The USAAF in February 1942 organized a provisional force, later designatedthe Antilles Air Task Force. Scattered about the Caribbean in Trinidad,Curacao, Aruba, St. Lucia, Surinam, British Guiana, Puerto Rico, St. Croix,and Antigua, it consisted of about 40 B-18 medium bombers, seven Douglas A20Havoc light bombers, and several fighter aircraft. Although remainingsubstantially the same size through the year, the task force obtainedradar equipped aircraft, vastly increasing its anti submarine capability.Prior to July the air crews reported few sightings of or attacks onsubmarines, but in July and August attacked 20. To supplement theseefforts, the 1st Air Force sent six B-18's equipped with radar to theCaribbean Sea Frontier. This unit, shuffled from one island and commanderto another from August to November 1942, accomplished little.

The U.S. Navy extended the convoy system to the Caribbean Sea Frontier,with the first convoy sailing on 10 July 1942, between Guantanamo, Cuba,and the Canal Zone. In reaction, Admiral Doenitz redeployed his submarinesto the Trinidad area where targets were lucrative and relativelyunprotected. In August, the submarines sank only one ship in the rest ofthe Caribbean while destroying ten near Trinidad. Because of the extensiveCaribbean air patrols, the submarines attacked independently, continuingtheir success into September, sinking an additional 29 ships totaling143,000 tons.

The USAAF stationed detachments of B-18's at Trinidad, Curacao, DutchGuiana, and British Guiana in June 1942; but these aircraft, lacking radar,could not stem the German efforts in the area during July and August. On 17August, to aid the Caribbean Sea Frontier, the USAAF sent a detachment ofB-18's equipped with microwave radar to Key West, Florida. The detachment,which always patrolled the Trinidad area, moved to other bases in theCaribbean and was based at Trinidad between 22 September and 16 October 1942.

OPERATIONS OF THE US ARMY AIR FORCES anti submarine COMMAND

OCTOBER 1942 - AUGUST 1943

By October 1942, the USAAF had been engaged in anti submarine war for almosta year. During that time it had laid the basis for an effectiveorganization and made plans for a larger anti submarine force. To takeadvantage of these plans, the USAAF on 15 October 1942, activated the USArmy Air Forces anti submarine Command (AAFAC) to replace I Bomber Command,which held most of the USAAF's anti submarine resources. I Bomber Commandfurnished the personnel, aircraft, and equipment for the new organization,which remained under U.S. Navy operational control. The AAFAC provided agreater unity of command of anti submarine forces in the War Department,resulting in increased flexibility and more effective operations. The IBomber Command had been handicapped in its efforts because its primarymission remained longrange bombardment. The anti submarine task wassecondary and presumably temporary. "Now," in the words of the officialhistory of the USAAF in World War II, "as an officially constitutedanti submarine unit, the AAFAC was able to attack its problems withundivided energy, free at least from any immediate uncertainty as to itsmission." The reorganization extended to subordinate elements as well. By20 November 1942, the AAFAC had organized the squadrons it had inheritedfrom I Bomber Command into the 25th and 26th anti submarine Wings withheadquarters at New York and Miami respectively.

In January 1943, the command had only 19 squadrons and only 20 B-24's, theaircraft type most useful for long range anti submarine patrolling. Thecommand grew rapidly until, by September 1943, there were 25 anti submarinesquadrons, most of which flew B-24's modified for anti submarine war. At theend of 1942, most of these squadrons operated in the Gulf, Caribbean, andEastern Sea Frontiers on endless patrols with few sightings and fewerattacks. The U.S. Navy continued to require the AAFAC to commit sizeableforces in these areas to counter what was a diminishing German threat thefive to ten submarines that Admiral Doenitz kept along the U.S. coast andin the Caribbean Sea. From September 1942 until mid1944 these fewsubmarines maintained pressure on the American anti submarine forces. Tocounter the submarine threat in the Caribbean, the Army Air Forcesanti submarine Command continued to fly patrols and escort coverage fromCuba. These operations, which had begun as early as June 1942, generallykept the German submariners from making successful attacks in the CaribbeanSea Frontier, although two ships were sunk there as late as July 1943.

The Germans found the hunting more profitable in the area of Trinidad untilmidyear 1943. The AAFAC consequently based B-18's at Edinburgh Field,Trinidad, from early January until August 1943. In November and December1942, German submarines sank 18 ships. Increased aerial patrols paid offwith no losses of friendly ships near Trinidad from January to July 1943.During this time, the USAAF B-18's engaged mostly in convoy escort andcoverage missions. In July-August, German submarines sank four merchantvessels. The USAAF anti submarine squadrons, flying both B-24's and B-18's,made six attacks and participated in two killer hunts to foil the enemyoffensive in Trinidad waters.

In addition to the Trinidad area, the German submarines operatedextensively in the South Atlantic Ocean in 1943, where merchant vesselssailed independently because there was no convoy system. The AAFAC sent adetachment of B-24 aircraft in May from Trinidad to Natal, Brazil, to patrolthe South Atlantic sea lanes at ranges beyond the reach of the Brazilian AirForce. The next month, the detachment moved to Ascension Island, added twomore aircraft, and flew patrols over the South Atlantic Ocean until August1943.

Although important, the AAFAC's operations from October 1942 in the EasternSea Frontier, the Gulf Sea Frontier, and the Caribbean Sea Frontierconstituted only a small part of the war against the German submarines. Infact, by midsummer 1942, the U.S. Navy's and the USAAF's anti submarinewarfare efforts had forced Admiral Doenitz to withdraw most of his forcesfrom these areas. The German submarines moved back to the North Atlantic toexploit weaknesses in Allied anti submarine efforts there. Consequently, theAAFAC turned to the reinforcement of the meager anti submarine air forces inNewfoundland.

OPERATIONS FROM NEWFOUNDLAND

OCTOBER 1941 - JULY 1943

In October 1941, far to the north, an USAAF detachment of four to sixB-17's had begun anti submarine patrols over the northwest Atlantic Oceanfrom Gander Lake, Newfoundland. The B-17's were armed with machine guns andbombs but carried no radar or depth charges. In July 1942, the 421stBombardment Squadron (Heavy), also flying B-17's and with a primary missionof long range bombardment training, replaced the detachment. The squadroncooperated with Royal Canadian Air Force and U.S. Navy organizations inNewfoundland to carry on its secondary mission of anti submarine war. Then,in the fall of 1942, the Army Air Forces anti submarine Command madeanti submarine patrol the squadron's primary mission, re designating it the20th anti submarine Squadron (Heavy).

The 421st had replaced the B-17 detachment in Newfoundland even as theGermans increased submarine activity in the 500mile (805 km) gap between 25and 45 degrees West longitude that the Allies could not cover withland based aircraft. This gap in air coverage allowed the German submarinewolf packs to attack convoys without being spotted or attacked from theair. Admiral Doenitz organized the submarines in two screens running in anorthwesterly direction at either end to catch the convoys as they sailedinto the gap. The sea lanes northeast of Newfoundland, marking the easternedge of Allied air coverage, were especially dangerous.

The Allied convoys sailed under several other disadvantages from September1942 until March 1943. Fuel shortages kept them close to the shortest trackto and from Great Britain. Winter weather favored the submarines whichoften approached the convoys without being detected until too late. Formost of 1942 the British could not decipher Enigma transmitted code, butthe Germans could read the Allied convoy code. The Germans located andintercepted Allied convoys more frequently and successfully during thisperiod than at any other time in the war.

Germany redeployed its submarines to the mid Atlantic in June and July 1942,and the offensive became effective in July and August. By then, the enemyhad 86 submarines in the North Atlantic, and approximately this numberremained operational there until June 1943. In August and September 1942,the submarines located 21 of 65 convoys that sailed, attacked seven, and sank 43 Allied ships.

During the Allied Conference in January 1943 at Casablanca, French Morocco,Great Britain and the United States agreed to deploy B-24 aircraft to patrolthe mid Atlantic gap. Modified B-24's, with a radius up to 1,000 miles(1,609 km), could fly day or night in all but the worst weather to detectand attack submarines. The British immediately began operating Liberators,the Royal Air Force designation of the B-24, from bases in Ireland andIceland to cover the eastern part of the gap, but the U.S. Navy did notsend any aircraft to cover the western stretches of the mid Atlantic. DuringFebruary 1943 21 ships totaling almost 200,000 tons were lost, mostly inthe western gap. The next month in the Atlantic, the Allies lost 38 shipsof 750,000 tons and an escort in four convoys.

On 18 March a B-24 detachment of the 25th anti submarine Wing established aheadquarters at St. John's, Newfoundland, and began anti submarine patrolson 3 April 1943. By the end of the month the Army Air Forces anti submarineCommand had three B-24 squadrons operating from St. John's and Gander Lake,Newfoundland. The squadrons engaged in convoy coverage and in broadoffensive sweeps ahead of the convoys. In April and May they made 12sightings of German submarines, which resulted in three attacks, but theB-24's did not sink a submarine.

During April 1943, Allied long range B-24 aircraft and escort carriers closedthe mid Atlantic gap in air coverage, effectively neutralizing the Germansubmarine offensive. That month the Germans sank only three Allied merchantvessels while losing four submarines. In May Germany lost 31 submarines inthe North Atlantic, and on 26 May, Admiral Doenitz withdrew his boats fromthe North Atlantic, essentially conceding victory to the Allies in theBattle of the Atlantic. Almost 1,700 Allied ships crossed the ocean in Juneand July 1943 without a loss.

The Battle against the U-boatin the American Theater
Part I
Part II
Part III

Allied air forces