U-Boat Monthly Report - Mar 1943

8/6/2019 U-Boat Monthly Report - Mar 1943

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lonthly. intelli pnoe report No. 3. AAFntisubmarine Camand.... r- ..

This DocumentISA HOLDING OF THEARCHIVES SECTIONLIBRARY SERVICES

FORT LEAVENWORTH, KANSASDOCUMENT NO. R 145 COPY NO. _CGSC Form 160 Army-CGSC-P3-1966-20 Mar 53-5MM .,. K1


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CONTENTS

I ANALYSIS OF SUBMARINE WARFAREA. Allied Shipping Losses. . . . . . . . .B. Attacks on Convoys. . . . . . . . . . .C. Genrman Strategy in Disosition of ubma

Protection . . . . . . . . ......t Bases . . . . . . . . . . . ....Submarine Warfare . . . . . .....

IV AT THAT

VII THE

WEATHER

X OPERATIONAL STATIS

highlycaut ion


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A 2M1 j_ / L~jE

ANALYSIS OF SUBMARINE WARFARE

CHART I

A. ALLIED SHIPPING LOSSES

During the month of February the downward trend of sinkings of Allied and neu-tral merchant vessels evident since November was abruptly reversed. In March, theenemy submarines were even more successful with the result that losses were more than60% greater than in February, reaching the high level of last October. Reports forthe early part of April are more encouraging, indicating a sharply lower rate ofsinkings.

Chart I shows the record of monthly tonnage losses as a result of submarineaction since September 1939, as well as the tonnage loss of tankers and cargo passen-ger vessels. The curves shown on the chart are based on British figures prior toSeptember 1942, and American figures thereafter. The American figures include shipsthat may have been used for transporting troops, regardless of whether the ships wereclassified as commissioned auxiliaries.

The loss of ships from enemy action of all types, including mines, air and sur-face craft, as well as submarines, is shown in the following table for the months ofMarch and February 1943. The February figures have been revised slightly from thetotals shown in this report last month as more accurate information concerning sink-ings during the month became available.

-~r~w ~


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OF SINKINGST S SUNK BY ENEMY ACTION

AreNorth Atlantic Convoy Area . . . . .Mid-Atlantic Area . . . . . ... . ....Gulf Sea Frontier . . . . . . . . ...Caribbean Sea Frontier - Eastern.Caribbean Sea Frontier - Western ...Brazilian Area. ...........Northeast Atlantic - Northern . .Northeast Atlantic - Southern .Southeast Atlantic .. . . . . . . .Mediterranean and Red Sea .......Indian Ocean Area . . . . . . . . . .Pacific - Central ... . . . . . . . .Pacific - Southwest . . . . . . . . .

TOT

Talkers . . . . . . . . ...Cargo and Passenger Vessels .Small Vessels 50-1000 tons..

TOTAL

March 1943Ships Gross Tons

. 37 231,135

. 2 11,090

. 1 2,493

. 5 27,386

. 6 32,343

. 20 95,436. 15 87,800. 9 68,640. 13 73,467. 3 19,339

3AL 114

6107

1114

7,435656,564

47,890608,546

128656,564

February 1943Ships Gross Tons

341

1

27855

2267

1649267

216,1304,312

-

7,957-

9,52835,54148,54727,91517,316

7,36311,988

386,597

125,531260,931

135386,597

Note: Tabulation includes 9 vessels overdue and presumed lost in March.

AREAS: This month marked the return of the U-boats to coastal waters with a conse-quent increase in the number of sinkings in these areas. One ship was sunk in theGulf Sea Frontier,-the first since September; five in the Caribbean, and five moreoff the bulge of Brazil. Shipping around the southeast coast of Africa also sufferedfrom increased submarine activity during March, nine merchant vessels being lost.

In addition to these successes in areas at considerable distance from theirbases, the U-boats intensified their efforts against merchant shipping along thenorthern convoy routes. Indeed, the increase in sinkings was very general, extend-ing to almost all parts of the North and South Atlantic.

LOSS OF CONVOYED SHIPS: The percentage of ships lost that were either in convoy orwere stragglers from convoys remained high during March, 84 of the 114 merchantvessels sunk falling in this category. It is noteworthy that 34 of these losses wereconcentrated in three convoys. All of these heavily attacked convoys were east-boundand presumably loaded with highly strategic war materials. In previous months theheaviest attacks fell on west-bound convoys carrying less essential cargoes. Furtherdetail on the North Atlantic convoy operations for the month of March is included inSections I-B and II-C.2

A. SF.EI


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TYPE OF SHIPS SUN1qER L:-of the 114 vessels lost in oMarch were tankers. Thisproportion is markedly lowerthan in previous months. InFebruary, for example, 16 otankers totalling 125,531 tgross tons were sunk. VOY REA (NORT)TYPE OF ENEMY ACTION: The MID-ATLANTIC .U-boat fleet accounted for101" of these merchant vessel osinkings or a total of \EAS'T NcsF587,835 gross tons. Twelve .vessels aggregating 67,861 0 agross tons were lost due to SE.ATLANTICaction of enemy aircraft , and AZLI AREAone small vessel was sunk bya mine in the North Sea.MARINE CASUALTIES: There was 6- 0 20 0 20 40an unfortunately large number CHART I

CHART IIof marine casualties in March.Sinkings, March 1943Twenty-three ships, as well as

their cargoes, were removed from further service in the war effort by this cause.DAMAGED BUT NOT SUNK: In addition to vessels destroyed, forty-two ships were damagedby enemy action during the month but either succeeded in reaching port or were beached.

B. ATTACKS ON CONVOYS

A wealth of interesting data on convoy activities between the general region ofNewfoundland and the United Kingdom is contained in the March report of the Commanderof Task Force 24, United States Atlantic Fleet. Selected significant figures fromthis report are given below:

January February MarchNumber of Ship Crossings. . . . . . . 581 510 617Average Number of Convoys at Sea. . . . . . 5.64 4.89 5.52Average Number of M/V's per convoy.. . . . 38.5 45.5 44.0Average Number of U/B's at Sea. . .... . 44.7 47.0 56.7Average Number of U/B's per Convoy..... 8.0 9.6 10.3Average Number of Escorts per Convoy. ... 6.3 7.2 7.1Average Number of M/V's per Escort. .... 6.1 6.3 6.3Number of M/V's sunk. . . . . . ......... 2 24 35*Percentag oI /V's sunk.......... 0.35 4.71 5.68

*This report apparently wasl bas - data available early in April.It ap ahL t total~~i 42 shps re lost in this general areaduri ng atnch i ailb er in 3L~Ct~I


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Important March changes in he convoy battle in he North Atlantic appear tohave been, first, the volume of shipping increased, second, th e average number of U-boats increased relatively more than th e volume of shipping and, third, sinkingsgained more than either of these factors, with the result that both the percentageof shipping lost and th e sinkings per U-boat increased.

Ship crossings numbered 617 during the month with the average number of convoysat sea amounting to 5.52 in arch as compared with 4.89 in ebruary, while the aver-age number of ships per convoy was only slightly smaller than in the preceding month.

The loss in terms of shipping volume was heavy with 5.68% of the merchant ves-sels lost as compared with 4.71% in ebruary and 4.44% in ecember. A somewhat en-couraging factor, however, is that enemy successes per U-boat operating in he areawere smaller than in December, although slightly larger than in ebruary. The sink-ings were largely concentrated in four badly hit convoys, HX-228, SC-122, SC-121, andHX-229. Each of these four convoys was beset by a large pack of U-boats; those onSC-121 and HX-228 being estimated at ten each, while as many as 26 were thought to bein the vicinity of HX-229 and SC-122 at the time when they were being attacked simul-taneously.

Variations in the volume of shipping and in convoy protection were not suffi-ciently great to account for the marked increase in sinkings and it appears that thefollowing factors were primarily determinative:

(1) Increase in Submarines. The number of U-boats at sea in this areaaveraged 56.7 as compared with 47.0 in February, 44.7 in January and 37.0 in ecember.In addition, each U-boat had somewhat better operating results since, on the average,the sinkings per U-boat-month was .6 ships in arch as compared with .5 in ebruary.This increase in sinkings per U-boat was due probably to other factors such as unfor-tunate routing, weather and, possibly, the use of new weapons and equipment.

(2) outing. Storms, ice-floes or other factors required routing three ofthe four badly hit convoys south of the great circle route,--an area that is outsideof normal air range and one that had proved excessively dangerous to.convoys in Febru-ary and in ecember. Only one convoy on the most northern routes suffered a very dam-aging attack.

(3) eather. Weather, particularly on the routes south of the great circle,was less severe than in February which made it easier for U-boats to sight, trail andattack convoys.

(4) ossible New Weapon. It is believed that some enemy submarines areusing a new torpedo that is probably acoustically controlled. The extent to whichsuch a torpedo is eing used is not known but conceivably it could account for someincrease in sinkings. It is also believed that U-boats are now equipped with detec-tion devices which may be giving them in certain cases an an- warning of theapproach of surface craft or aircraft.


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C. GERMAN STRATEGY IN DISPOSITION OF SUBMARINESThe enemy's main use of U-boats during March was in the North Atlantic in an ef-

fort to intercept European bound convoys. Roughly, there were about 57 U-boats oper-ating along the North Atlantic convoy routes or slightly more than on e half of theU-boats believed to have been at sea in all areas. In addition, there was a widedispersal of U-boats to the United States coastal waters, the Caribbean, the BrazilianCoast, th e West African Coast and the Cape of Good Hope-Nozambique area. To accom-plish this concentration in the North Atlantic convoy routes and this dispersal todistant areas without increasing the totalnumber of U-boats at sea, it,as necessaryfor the enemy to reduce the heavy concentration that was formerly maintained in theAzores-West African region.

The best available intelligence has indicated for some months that th e enemy hadin he neighborhood of 450 U-boats and, furthermore, that production was so outstrip-ping destruction that his total U-boat force was increasing at a rate of ten tofifteen submarines per month although some recent unsupported reports have indicatedthat air bombing has reduced U-boat production below this level. Under such condi-tions it was expected that the total number of U-boats at sea would tend to increasesteadily or, at least, rise to a peak with the start of spring. There is, owever,no evidence to indicate such a result. In fact, it is estimated that the total ofU-boats at sea has been relatively constant for several months and well below atemporary peak of nearly 130 in ovember during the effort to hamper the expedition-ary force to Africa. Moreover, it appears that a further decrease took place in theearly weeks of April. The reduction of U-boat concentrations in the Azores area inorder to harry shipping in distant areas is also strange if th e enemy is actuallycapable of sustained operation of a much larger fleet at sea.

Various explanations of this situation have been offered, such as shortages ofoil or torpedoes, lack of trained crews and the hampering effect of bombing opera-tions on the U-boat bases. There is little evidence of an oil or torpedo shortageand the training of twenty-five crews per month to man new U-boats and to replacecrews lost should not be an impossible task. The most logical explanation seems tolie in he effect of bombing of the bases and th e increasingly aggressive nature ofair and surface attacks on U-boats at sea and air attacks on those in transit in andou t of the Bay of Biscay. It is known that havoc has been wrought by bombs in theseports through the destruction of workers' homes, storage facilities, power and trans-portation facilities. It has long been known that if the layover time of U-boats inport could be lengthened as little as one week th e effect would be to reduce thetotal number of U-boats at sea by as much as twenty-five per cent assuming that theenemy did not offset this result by drawing on additional reserves. In ddition,increasingly strong air patrols over the approaches to the Bay of Biscay have beenmaintained which tend to force frequent submergence and thus lengthen the transittime in oth directions. It is quite possible that destruction in the bases has beenso great as to cause congestion and force U-boats to return to smaller and less well-equipped bases along th e Norwegian coast. Except for those operating in he IcelandArea the useof such bases will result in a longer time in transit. Thus it seemsnot unlikely that the cumulative effect of'the strong RAF ard USAAF efforts to damagethe primary U-boat bases is becoming apparent.


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It would be a mistake,0 however, to assume from thisthat the enemy's striking

* ... power is in the process of0 00

0 0 o0 . immediate an d complete des-00 oo$ truction, since it is possi-Oo 0 o000o - ble that a substantial force

000 o of U-boats is being held in0 0 0 0 0 reserve for use later in the

year if important Alliedlandings are attempted in

0zo~Europe.0 0\ 0

The following are the0 more important capabilities0- 0 0 0 0 of the enemy in the North and

S o South Atlant ic, stated in th e- order of their probability:

(1) Continuing heavyS concentrations of U-boat packsSfor the purpose of interdict-Iooo a0d ras ' o I + ing Allied shipping along theconvoy routes between Newfound-

CHART II I land and United Kingdom.Est imated distribution o f enemy (2) Attacking shippingU-boates toari th e en d of March along convoy routes between th eUbots towardhe end of March United States and Gibraltar or

West Africa.(3) Operating minor groups of U-boats in various coastal and island areas of the

Atlantic Ocean for the purpose of containing disproportionately large Allied anti-sub-marine forces in areas remote from th e enemy's main effort.

(4) Holding a portion of his forces in reserve to be utilized as a strikingforce if the Allies attempt a European invasion.

(5) Operating U-boats for the purpose of laying mines in or near Allied harborinstallations and of landing enemy agents and saboteurs along Allied shores or main-taining communications with them.

While it is probable that he will exercise all of these capabilities in part,emphasis doubtless will continue to be placed upon the intercepting of convoys toEurope and Africa. This is the enemy's most vital strategic objective. To it he hasbeen devoting over half of his U-boat forces at sea. A reasonably proportionatecounter-effort of th e Allies in these areas appears essential, not only because it isequally vital to the Allied cause that shipping through these areas should reach itsdestination, but also because the density of the U-boats in proximity to such shippingprovides the most fruitful "hunting" for offensive activities.

The protection of the more concentrated Allied shipping in other areas is of con-tinued importance, especially in the light of greater sinkings per U-boat in some ofthese scattered coastal zones. This, however, must be accomplished without lesseningvigorous offensives against U-boats by sustained air hunts in areas of concentrationat sea, by constantly attacking submarines in the Bay of Biscay bottleneck and bydemolishing the enemy's bases and construction yards.

The U-boat continues to be a major threat to all Allied military operations, but itappears that the continued growth of Allied air power is being reflected in the U-boatoperatic-is just as it is on land in Tunisia and in the war output of Europe itself.6


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IIANALYSIS OF ANTI-SUBMARINE WARFARE

A. ANTI-SUBMARINE OPERATIONS BY AIRCRAFT

Eastern Sea Frontier and Gulf Sea FrontierThe average daily density of submarines estimated in these areas in March was

1.8. Less than two submarines per da y in over a million square miles of water ishardly a formidable concentration, but it is a significant increase over the Februaryaverage of 0.3.

The number of hours f lown by Army and Navy aircraft in these frontier showed acorresponding increase of more than 8,000 hours. A contributing factor to this trendis the gradual acquisition by AAFAC units of B-24 aircraft with their long endurance.As of March 31 three entire squadrons and a few detacbments had completed their tran-sition at the Operational Training Unit, and were equipped with B-24's. At the presenttime, it is estimated that two additional squadrons per month will be processed at,Langley. It may be expected then that not only a further increase in hours flown willresult but the area that can be covered by land based aircraft will be greatly extended.

A summary of hours flown by Army and Navy aircraft is presented in the followingtable. Detailed operational statistics for AAFAC Wings and Squadrons may be found insection X.

PATROL ESCORT SPECIAL TRAINING TOTAL HOURS

AAFAC......... 4592 742 684 6417 1279Army CAPCP* . . 9382 2275 - 115 11772

TOTAL 14334 3017 684 6532 24567

Navy Planes*. . . 9396 4302 1065 - 14763Navy Blimps . . . 3016 1617 239 5072

TOTAL 12412 6119 1304 - 19835TOTAL ARMY ANDNAVY.. ...... 26746 9136 1988 6532 44402

*Civilian Air Patrol planes are light, single-engine civilian types, andtheir patrol area is limited to a narrow zone along the coast where thedepth of the water restricts submarine activity. The majority of theplanes used by the U.S. Navy in the Eastern Sea Frontier are single-motored observation types which have a limited radius of action comparedwith the Navy PBY type and the medium and heavy bombers used by theAntisubmarine Command.

Squadrons on Foreign Service1st and 2nd Antisubmarine Squadrons: During March the 1st and 2nd Antisubmarine

Squadrons, operating as the 2037th Provisional Wing, changed station from United King-dom to Northwest Africa. The first plane arrived at Port Lyautey on March 9, 1943and operations in cooperation with the Navy were begun on March 19th. Three dayslater the first German U-boat sunk in this theater by an AAFAC aircraft was creditedto Lt. W.L. Sanford and his crew, of the 2nd Aron. Details of the attack are pre-sented under a subsequent heading.


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The 1s t and 2nd Antisubmarine Squadrons have done valuable work in England andhave pioneered in solving th e problems incidental to foreign detached service. Arecord of their operations, attacks and sightings according to records available atthese Headquarters 1s as follows:

Missions U-boatsNumber Hours Sighted Attacked

November, 1942 9 74 0 0December 30 257 2 2January, 1943 56 .483 0 0February 94 928 10 6March - From England 10 113 2 1March. - From Africa 43 372 1 1Seven times aircraft of the Squadrons encountered enemy aircraft and three enemy

planes were damaged or destroyed as a result. One of our aircraft is believed tohave been lost as the result of attack by enemy aircraft.

Of especial interest was an effort in ebruary made in cooperation with the CoastalCommand during a period when it was believed an unusually large number of U-boats werepassing through the approaches to the Bay of Biscay. This consisted of intensepatrolling in an outer area, largely west of 150 W., by the 1st and 2nd Squadrons andin an inner area by British aircraft. Based on estimates of the U-boats in the areaand on the assumption that they would remain fully surfaced all day, it was believedin dvance that 12 sightings should be made. Actually 13 sightings resulting in 7attacks were made in this area, - most of them by AAFAC squadrons. In the inner areathe British aircraft made 9 sightings and 3 attacks.

According to reports received the experience gained by these squadrons in ng-land was of great value and they are high in their praise of the Coastal Command whichthe Commanding Officer describes as th e "best organized and trained anti-submarine or-ganization in existence." The Coastal Command Review for February 1943 states thatthe impending withdrawal of "the two Anti-Submarine Liberator Squadrons (U.S.A.A.F.)is noted with real regret." In fact, these tw o Squadrons made 30% of th e sightingsand 19% of the attacks recorded by anti-submarine flights from the United Kingdom andIceland during February.

Port Lyautey situated between Casablanca and Spanish Morocco, isa United Statesbase, from which PBY's have been flying antisubmarine missions for several months.Facilities for replacement, parts and repair of B-24 type aircraft were non-existantso that one of the tactical B-24's had to be earmarked as a spare parts plane. Inorder to conserve aircraft, the number and duration of missions had to be temporarilydecreased. From the 19th to the 31st of March, 43 missions were flown totalling 372hours.

9th Antisubmarine Squadron: The 9th Antisubmarine Squadron based at Trinidadflew 910 hours on patrol during March, resulting in 3 sightings and two attacks. Al-though.the 9th Antisubmarine Squadron flew less than ten percent of th e total hoursflown in the Trinidad area during March, it as fortunate enough to record three ofthe four sightings made in the area during the month. The attacks were described inth e February issue of this publication under the title, "Killer Hunt in he Caribbean."


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Although equipped with B-18 airplanes only, which lack sufficient range to cover thearea adequately, the 9th Antisubmarine Squadron flew a total of 3,783 hours ou t ofTrinidad since November 1942, resulting in 7 sightings and 2 attacks.

Before th e end of March this squadron returned to the United States and th e 7thAntisubmarine Squadron was moved to Trinidad to replace it, eginning operationslate in the month.

19th Antisubmarine Squadron: The 19th Antisubmarine Squadron moved to Newfound-land during March to augment air coverage in that area and began operations fromGander. An exhaustive survey of the base facilities and flying conditions in Green-land was made by th e AAFAC Staff and it was decided to reinforce anti-submarine unitsin ewfoundland that would utilize Greenland as an advance operating base. A newprovisional headquarters, temporarily under the 25th Wing, has been established inSt . Johns, Newfoundland. This development is one of the most important in th e historyof the Antisubmarine Command and it involved a large amount of planning and action.Substantial progress on it has been made in April. As a result, trans-Atlantic con-voys should have greatly increased protection in the entire area stretching betweenNewfoundland and Iceland in the very near future.

20th Antisubmarine Squadron: The 421st Bombardment Squadron, located in ew-foundland, was redesignated as the 20th Antisubmarine Squadron and assigned to AAFACon February 8, 1943. Although the Squadron has only a limited number of aircraft inservice, it flew 370:30 hours during March and made seven sightings resulting in woattacks. Two airplanes on March 16th made six sightings of submarines, -- of whichtwo sightings are believed to have been of th e same U-boat. Each airplane made anattack but in both instances the bomb bay doors failed to function properly with theconsequence that only one depth bomb could be released in each attack. A slight oilslick was observed after one attack but there was no other evidence of damage.

B. ATTACKS ON ENEMY SUBMARINESDuring March, air and surface craft delivered a total of at least 113 attacks on

enemy submarines for an average of approximately one attack per U-boat at sea. Thisis substantially more than the forty-five attacks reported in ebruary and thirty twoin January. However, a direct comparison is ot possible on the basis of thesefigures as a number of attacks in the eastern half of the Atlantic are included thismonth, whereas, in previous months, little information of action in this area wasavailable for inclusion. This unusually high figure attests both to the growing ef-ficiency of Allied anti-submarine operations and to improved inter-Allied coordinationand communications. It also reflects the fact that in a month of high sinkings ofmerchant vessels, U-boats were forced to be more reckless and to increase their expo-sure to attack.

More than half the attacks were delivered by Coastal Command of the RAF, sixteenof them the result of an unusual air blitz over the Bay of Biscay. It has been notedthat U-boat traffic in th e Bay tends to fluctuate;- at times there are many in transit,at other times but few. An operation was planned whereby increased and continuouscoverage would be maintained during a period when a concentration of submarines was


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expected to be passing through thesewaters. This plan had been carriedout with considerable success duringa period in early February. Again inMarch, in the course of one week,1,340 hours were flown resulting in27 sightings and sixteen attacks.

No final evaluation of theseattacks has been received but a num-ber of them appear very promising. In

" . seven instances, the U-boat was sur-faced or partly surfaced when the

a depth bombs were dropped. No survi-vors are reported but the appearanceof significant quantities of oil and

AICRAFTTTACKSN U BOATS bubbles is mentioned. More than twoFEBRUARY-MARCH,943 EYattacks per day in so restricted an

area attests to the success of theoperation and justifies repetitionCHART IV under similar conditions.

In the North Atlantic Convoy area, surface escorts made a number of excellentattacks. Preliminary reports indicate 22 attacks resulting in t least four kills.U-444 was rammed and sunk on March 11 by joint action of Harvester and Aconite andfour prisoners were taken. Later the same day, Aconite attacked and sank U-432,yielding twenty on e prisoners. Harvester was subsequently torpedoed and sunk as shestopped to repair damage incurred in he ramming.

Aircraft patrolling in he North Atlantic delivered 35 attacks of which somerecord has reached this Command. No evaluation of these actions has been received.However, two U-boats attacked on the surface southeast of Iceland were last observedin lmost vertical positions and machine gun fire was directed against th e keel ofon e of them. After both attacks, large quantities of oil were seen and in one in-stance considerable debris appeared. In ten other reported instances, attacks weremade on surfaced U-boats, of which at least three were probably sunk.

In the Mediterranean, two attacks by RAF planes were assessed as lethal. Oneattack In the vicinity of the Canaries by a B-24 of the 2nd Antisubmarine Squadronresulted in he sinking of the U-boat and is reported in detail in Section VI-A. Inthe waters northeast of Trinidad, a PBY executed a successful attack which was des-cribed last month.

Although assessments are preliminary and incomplete, it is stimated that atotal of 15 to 20 attacks will be evaluated as resulting in U-boat sinkings or prob-able sinkings during March. Three fourths of these were accomplished by aircraft.Thus, March appears to have been one of the most successful months on record, ex-ceeded only by November when a large number of attacks were made on the concentra-tions attempting to prevent the landing of the expeditionary force in frica.

The accompanying chart shows th e positions of all aircraft attacks on submarinesduring February and March on which information has been received at these Headquarters.Attacks in hich presence of a submarine is doubtful are not shown and it is probable


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that the actual number of aircraft attacks on submarines exceeds the number shown. Itis evident that U-boats have reason.for increasing fear of aircraft, and the number ofattacks by land-based aircraft carried out far from land is particularly worthy ofnote. More and more attacks far from land are, certain as additional VLR aircraftbecome available.C. INCREASED CONVOY PROTECTION

Land Based Air Coverage. Substantial increases are being made in the number ofVLR aircraft available for escort and protective sweep operations around convoys. De-velopments in this respect are important and promise nearly to eliminate the mid-oceangap in coverage on the more northerly routes. Newfoundland and Greenland are becomingimportant bases from which long range aircraft can reach far at sea and increasedforces are contemplated for the Caribbean, Brazilian and African areas.

Heavier Escorts. The Commander of Task Force 24 reports that the number of es-corting vessels at sea with th e North Atlantic convoys, having shown no change duringseveral months prior to March, has now begun to increase and the average for March was11% over that for February.

In he matter of escorting vessels the Allied Nations are fortunate in that threeBritish support groups have now been assigned to duty in the North Atlantic. One ofthese is already in peration and gave valuable assistance during March. She joinedSC-123 at a critical time and may well have assisted in averting attacks. When thethreat to SC-123 passed, this group shifted to HX-230 which was being threatened. Inneither case did attacks on these convoys develop, the one ship sunk ou t of HX-230being a straggler when torpedoed. It is xpected that as the DE (Destroyer-Escort)program gains momentum, escort strength will be progressively increased.

Aircraft Carriers. March marked the beginning of planned aerial escort of con-voys in he North Atlantic by carrier based aircraft.

One carrier was at sea for eight days. Because of weather, flying was possibleon only five of these days with occasional showers and snow on four of the five. Thesea ran moderate to heavy swells on three of the five days and was relatively calmwith a few white caps on the other two. Eighteen flights were made for a total of 38.9hours, an average of 2.16 hours per flight. All flights were by TBF planes having ASVradars. Two attacks were made, one on a certain U-boat and the other on a possibleone, more probably a fish. Another possible sighting of a periscope was also made.

A preliminary report from another carrier operation indicates 23.3 hours of fly-ing with no contacts by aircraft. However, shortly after planes had searched theregion of the convoy and landed on the carrier, a D/F contact was obtained and a U-boatsighted and attacked 20 miles astern the convoy by a surface escort vessel. This lastincident suggests the use of a radar detecting device by the U-boats, or that an es -pecially alert lookout for planes is ow maintained even when out of range of landbased planes, - a natural immediate consequence of the enemy's discovery that we areusing carrier-based coverage, but one that should give small comfort to U-boat crews.

Helicopters. Section VII deals with th e possible future use of helicopters. Asfar as is nown at these Headquarters, use of helicopters at the present time ispurely experimental in spite of stories that have appeared in the press indicatingextensive use of these craft as an anti-submarine weapon.


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* ~ u ~__;CHART9Bobn ad nUbatBssadCneso Ueae ActivityAVEour-lrh 1943


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D. ATTACKS ON U-BOAT BASESAlthough the month of March sa w a new record established for the number of tons

of bombs dropped on Europe, there was a decrease (as against the February figures) inthe number of attacks directed at the home bases of Germany's submarine campaign. InFebruary seven attacks were made on operating bases and eight on construction yards.In arch there were four attacks on the bases and three on construction yards. Severalindustrial cities such as Berlin, Essen, Duisberg and Stuttgart which produce compon-ent parts of submarines have been targets for repeated attacks. Chart V indicatesthe number of raids that have been made on U-boat bases and related strategic objec-tives during the first three months of 1943.

During March the RAF and U.S. Eighth Air Force bombed three of the operatingbases on the west coast of France: St. Nazaire (twice), Lorient and Brest. Both ofthe St. Nazaire raids were heavy; yet they were carried out by the RAF at a totalcost of only three aircraft. On the 22nd 300 RAF bombers attacked this base success-fully despite bad weather conditions, a significant sign of progress in the masteringof this important meteorological problem. On the 29th another heavy and concentratedattack, which has been compared in ffectiveness to th e 1,000-ton raid of February28, scored hits on docks and started large fires. Brest and Lorient were pounded byUSAAF bombers on March 6th. In this operation AA fire was reported as moderate tointense, while the fighter reaction was only moderate.

After the second attack on St . Nazaire some observers estimated that the heavybattering this port has received may necessitate its abandonment as a major submarinebase. This prediction seems over-optimistic at this time, but there can be no doubtthat great damage is being done to St. Nazaire. The Lorient attack is believed tohave stopped traffic for several days, while the electric power station is thoughtto have been put out of action and the arsenal destroyed. Photographs show most ofthe houses in he town roofless and gutted.

Several centers of submarine construction and repair activity were lined up inthe sights of RAF and USAAF bombardiers; Rotterdam, Wilhelmshaven, Nuremburg,Hamburg and Vegesack among them. Especially noteworthy was th e attack on theU-boat construction yards at Vegesack - an outstanding success which was cited asfinal proof of the efficacy of the daylight precision-bombing tactics of theUSAAF. More than 115 bombers made the 800-mile round trip, penetrating deeperinto the Reich than they had yet gone. A record load of high explosives wasdropped with a high percentage of hits. Photographs of the submarine-buildingships revealed that seven of the fifteen U-boats under construction at Vegesackwere severely damaged, and interpreters who examined the pictures estimated thatthe yards would be unable to make a substantial contribution to Germany's sub-marine construction program for many months. The unescorted Fortresses andLiberators which made the raid lost only two of their numbers in fighting off150 attempts at interception. Meanwhile, they ran up an imposing score againstthe German pilots; 52 enemy fighters destroyed, 20 probably destroyed, and 23damaged.


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Among the related targets bombed in arch, transportation centers figured prom-inently. Important junctions on railroad lines leading to the coast and the U-boatbases were given special attention: Rouen was hit three times, Morlaix (where a300-foot viaduct offers a particularly attractive target) twice, and Rennes once.

Two interesting defensive moves were noted during th e month. A redistributionof German fighter strength was effected, apparently with the intent of bolsteringdefenses over the sensitive west coast of France. And on th e 22nd heavy bombersover Wilhelmshaven and St. Nazaire had to find their targets through a smoke screen.Judging from results this screen was not overly effective, for the USAAF Fortressesand Liberators packed the target with hits at Wilhelmshaven, and the RAF raid onSt. Nazaire was termed successful.

Evacuation of the civilian population continues along the European coast line.Lorient has long since been abandoned by its non-essential inhabitants, and St .Nazaire recently lost 55,000 of its occupants. For "security reasons" La Palliceis being evacuated by civilians, and "a state of emergency" has been proclaimed forthe entire Netherlands coastal area. Extra trains carried all women and childrenfrom Wilhelmshaven after the February 26th bombing. Obviously, bombing of submarinebases is ot solely responsible for these moves; the fear of invasion plays a largepart in the decision to issue evacuation orders. Still, there is vidence in theLorient, St . Nazaire and Wilhelmshaven evacuations of the power of the anti-submar-ine bombing campaign.

E. SUMMARY OF ANTI-SUBMARINE WARFARE

The pattern of intensified anti-submarine warfare is now becoming clear andconsists of increased protection of convoys through heavier escorts plus the fullweight of growing air power utilized in four ways:. (1) ugmented convoy protectionthrough nearly continuous air coverage and protective sweeps by strategically lo-cated VLR aircraft and carrier-based aircraft, (2) oncentrated offensive air opera-tions in the approaches to the Bay of Biscay, (3) intensive air operations in otherareas of frequent U-boat concentration such as the Caribbean and the North Africancoast and (4), continued air offensive operations against th e U-boat bases, yards andcomponent parts factories.

Differences of opinion exist as to the relative efficiency of these various airoffensive operations with proponents of each advancing excellent arguments. Irre-spective of the merit of the opposing contentions, the air offensive against theU-boat appears to be gathering momentum in all phases and, as noted in he sectionon German strategy, may account for the apparent lack of increase in the U-boats atsea. With additional aircraft and new weapons soon to be available and with thenew offensive spirit supplanting the older one of simply protecting shipping at sea,it is expected that U-boat casualties will soon begin to outstrip production.


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IIIVALUE OF AIR ESCORT TO CONVOYS

It has long been known that aircraft are of immense value in protecting convoysand recent issues of this report have outlined the history of several convoys andshown pertinent charts bearing on the subject. Data has been lacking, however, tomake a comprehensive study that would evaluate accurately the degree of safety pro-vided by air escort. A most comprehensive study of the subject has been made re-cently by British authorities. While, admittedly, data is still insufficient fo rcomplete accuracy, th e results are convincing as to the extraordinary value providedby air coverage.

Much of the report deals with surface craft protection, the size and speed ofconvoys and other factors that are not of primary concern to those engaged in the airwar on submarines. These conclusions may be summarized briefly as follows:

1. The present scale of surface escorts is ot adequate to ensure relativesafety of convoys unless there is ir cover.

2. Increasing th e average surface escort from 6 to 9 vessels would reducelosses by about 25%. It is estimated that as the result of both offensive and de-fensive activities each escort vessel saves about 2 ships per year from being sunk.

3. Sinkings per convoy do not appear to increase substantially as the sizeof convoys is enlarged.

4. The number of U-boats attacked per U-boat operating does not increase withthe escort size which suggests that surface escorts have mainly a protective and de-fensive value.

5. The value of speed in th e convoy is learly marked. An increase in speedfrom 7 to 9 knots serves to reduce losses by 43%.

The portion of the report of chief interest to the Army Air Forces AntisubmarineCommand is that which. eals with the protection afforded to convoys through air cover.This section concludes that for th e convoys studied air cover of four eight-hoursorties per day served to reduce losses by 64% as compared with theoretical reduc-tions of 25% if escorts were increased from 6 to 9 or 43% if speed were increasedfrom 7 to 9 knots.

In aking this report, study was given to the records of all shadowed convoys inthe North Atlantic from August to December 1942. The principal factors were the num-ber of days and nights during which U-boats were known to be in ontact, the size ofthe pack, the ship losses during the period and whether or not air cover was provided.It was found that there were 43 convoy days (dawn to dawn) when shadowing took placewhile no air cover was available, and during these days, 75 ships were torpedoed bypacks averaging 5.3 U-boats in size. On the other hand, there were 38 days of shadow-ing in hich air cover was provided through 147 sorties and only 24 ships were torpe-doed by packs of the same size. The average air cover was only two hours per sortie,yet 62 sightings and 43 attacks on U-boats were made or 2.4 sorties per sighting and3.4 per attack.


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This comparison indicates that if it had not been for air cover these convoyswould have been expected to lose 67 ships rather than 24 or a saving of 43 ships; --one-third of a ship per sortie. The report estimates the operational life of a B-24or a B-17 at 40 sorties but this may be unduly pessimistic since past experience ofthe Coastal Command indicates a life of roughly seventy sorties. Even on the basisof a 40-sortie life, however, savings of one-third of a ship per sortie indicatessavings of 13 ships by defensive action for each aircraft expended.

The report goes on, however, to compute the offensive value of these sorties byusing the experience of th e Coastal Command that 8% of the attacks by aircraft onU-boats are lethal. In these air covered convoys, one attack was made for every 3.4sorties which, on an 8% lethal basis, means one U-boat sunk for every 42 sorties.It is further computed that the sinking of one U-boat is equivalent to saving 3ships. Thus the report estimates that each long range aircraft during its operation-al life will save 16 ships; -- 13 through defensive action and 3 through offensiveaction.

While all of these figures are based on somewhat inadequate data and while thecomputed savings through offensive action may be questioned if he U-boat destroyedis immediately replaced by another one from the U-boat reserve, the comparison of asavings ,of2 ships per year per escort vessel, with a saving of 16 ships in the 40-mission operational life of an aircraft is very convincing. This large saving wouldbe made in a five month period on a basis of two missions per week. Even if ueallowance is made for inadequate data or statistical error, the value of aircraftseems amply demonstrated.

It should be recognized that the value of aircraft to threatened convoys hasbeen due primarily to two factors:

(1) he use of aircraft forces U-boats to operate further at sea, thus makinginterception more difficult and limiting the area in which large scale attacks canbe developed.

(2) The use of aircraft forces U-boats to remain submerged and to proceed at avery slow speed with the result that packs are hampered in gathering in time to make alarge scale attack or the contact with the convoy is lost through its evasive action.

The extremely high value of VLR aircraft in his connection is due largely tothe favorable circumstances for action around a convoy in which a large number ofU-boats are present in a relatively small area and during a period in which most ofthem will be on the surface a large proportion of the time in order to keep up with,or gather around, the convoy. No such return would appear if all routine coastalpatrols were included but this study was limited to convoy protection and, as oftenpointed out in these reports, the submarine war is rapidly becoming a struggle primar-ily between the trans-Atlantic convoy and th e U-boat pack. The sporadic attacks byU-boats in coastal areas are in the nature of holding attacks designed largely to dis-perse and to contain our anti-submarine forces in areas far removed from the placewhere the enemy is aking his main effort, i.e., the North Atlantic.


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IvATTACKS THAT FAILED AND WHY

It as reported in last month's issue of this publication that a recent study ofattacks on submarines in the U.S. Strategic Area during the year 1942 had revealedthat only 4% of the attacks could be assessed as lethal. The percentage of attacksthat failed to prevent the return of the U-boat to its base was, therefore, as highas 96%. This was true of attacks by both air and surface craft.

In order to determine, in he case of the aircraft attacks, the reasons for thefailure of so many attacks, a further more detailed analysis was made of the attacksduring the last six months of 1942. In this period, there were 296 aircraft attacksin the U.S. Strategic Area, of which 219, or 74% were assessed to have been attackswhere a U-boat was present.* These attacks may be summarized as follows:

No. of AttacksEstimated Results of Attack July-Dec., 1942Sunk or probably sunk 11Probably damaged 50Insufficient evidence of damage 67No damage 91

TOTAL 219

It will be noted that, during this period, 5% of the attacks resulted in sinkingor probably sinking the U-boat and 23% damaged th e U-boat but did not sink it; indi-cating a somewhat better record for the second than for the first half of the year.In another 31% of the cases there was insufficient evidence of damage. Comparisonof this last group with the attacks which resulted in either sinking or damagingthe enemy submarine has disclosed no very significant differences in either the con-ditions surrounding the attack or the tactics employed by the attacking crew.

However, th e remaining 41%, that is, he 91 attacks which resulted in no damageto the U-boat, reveal certain very interesting facts when studied in etail. Thereport submitted,by the pilot of the attacking aircraft, the comments of the Com-manding Officer of the squadron, and all other endorsements have been noted. Aneffort has been made to determine from these data the principal cause of th e failureof each attack. The results are summarized in the following table:

*Attacks by blimps and CAP aircraft are excluded from this analysis because of thedifferent circumstances involved. Also excluded are attacks involving more thanone aircraft or aircraft coordinated with surface craft.


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REASONS FOR FAILURE OF ATTACK(Aircraft Attacks on U-boats, Assessed as Resulting in No Damage)

A. Attack Delivered Too LateU-boat detected plane at too great a distance . ........ . 8Too slow in executing attack. 5Insufficient opportunity to make attack ............. 1Reason undeterminable ...... ............ .... 4

18B. Tactical Errors

Bombing error . . . . . . . . . . . . . . . . . . . . . . . 29Insufficient number of bombs dropped. . . . . . . . . . . 3Fuze setting too deep . . ..................... . 3Poorly coordinated attack, evidencing insufficient experience . 439

C. Mechanical FailuresBombs failed to release .... ....... . . . . . . . . . . 6Firing switch failed to opperate . . . . . . . . . . . . 2Intervalometer failure. . ................ . 2Rack failure ................... .... . 2Depth Bomb duds .......... . . ............ . 3Inadequate night illumination . ................. 1

10D. Miscellaneous

Attacked oil slick. . . . . . . . . . . . . ... . 3Disappearing radar contact, attacked swirl ................. . 1Neither A/S equipment nor personnel . . . . . . . . . . . . . 4Insufficient data to permit analysis. . .............. 2028

E. Total . . . . . . . . . . . . . . . . . . . . . . . . . .. . 95**In four instances, the bombing error was accompanied by mechanical fail-ures of sufficient importance that it seemed unwise to attempt to selecta single "cause". This accounts for the total of 95.

A. Attack Delivered Too Late., The importance of flying at the best patrol alti-tudes, maintaining a vigilant lookout, and making proper use of sun, moon and cloudcover in order to avoid detection by the U-boat, the importance of speed and thefinest coordination on the part of the crew in delivering the attack, all these arestrongly reemphasized by the figures on lateness of attack found under thisheading.

There were seventeen instances where the U-boat had been down so long when thedepth bombs exploded that its location could not be known with any degree of accur-acy, either in plan or depth. In eight of these attacks it was felt that the sub-marine detected the plane at a distance such that even the fastest anti-submarineplane and crew could not have arrived in time to make a successful attack. Slownessin executing the attack (the fault 'could lie with either the crew or theplane) accounted for another five cases. In addition, one attack failed whenthe depth bombs were hurriedly released on a submarine which was sighted justbelow the surface directly beneath the plane. In the remaining four in-stances, the reasons for the tardy arrival could not be determined from thedata available.


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the development of bomb sights particularly adapted to this type of bombing, andthrough the proper spacing of bombs in he train were described in the February issueof this publication. Flat nose depth bombs, torpex, MAD, and sono-buoys are otherrecent developments with which our anti-submarine aircraft are already, or soon willbe, equipped. These and other related subjects have been presented in detail in re-vious issues of this summary. Meanwhile, experiments continue on other improvements.

Unquestionably, th e greatest opportunity for improvement of the overall resultsof aircraft attacks on U-boats lies in this field. And the most important singlefactor affecting the accuracy of bombing is training. A number of attacks, for in-stance, failed because of nothing but "buck fever". Bomb bay doors opened too late,firing key switch in rong position, practice bombs dropped instead of live bombs --these are errors resulting from lack of sufficient training and experience.

Practice in ropping dummy bombs on friendly submarines or suitable submersibletow targets is he most valuable type of training to increase bombing accuracy. TheFebruary issue described a program of bombing practice inaugurated in he 26th Wingand also an improvised tow target developed by the 22nd Aron. It is xpected thatintensive bombing training with actual submarines and adequate tow targets will beavailable for all AAFAC units in he near future.

C. Mechanical Failures. It ust be remembered that the table presented onlyth e principal reason for failure of each attack. Therefore, there were more instancesof mechanical failures in the 91 non-damaging attacks than the table indicates, but inthese additional cases, the location of the bombs or the period of time since th e U-boat disappeared was such that it was believed that the attack would not have beensuccessful even if there had been no mechanical failure.

For the sake of the record, however, there were, among the 91 attacks, nine in-stances of depth bomb duds and nine cases where some of the bombs failed to release.Some of these failures can be blamed on faulty maintenance and others on inexperience.Improved equipment, the result of continual research by the armament and ordnance sec-tions of both th e Army and th e Navy, ill eliminate some of the mechanical failures. Ex-perienced combat crews and efficient ground crews will prevent th e others from occurring.

D. Miscellaneous. This final category includes twenty-eight attacks of whichtwenty could not be analyzed from the meager data available. Four attacks were made byplanes and personnel neither trained nor equipped for anti-submarine operations. In thefour remaining instances, the U-boat was never seen by the attacking crew, three of theattacks being on oil slicks and the other on a swirl following a disappearing radarcontact.

E. Summary. The analysis of these 91 attacks has confirmed the urgent need fortraining, especially in ombing, and the necessity of avoiding detection while patrol-ling. It is xpected that significant improvement in both phases will follow the currentintensive training program. The end to be achieved is exemplified elsewhere in thisissue--the second attack described in the article "Tidewater Tillie Tames Two"


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ANTI-AIRCRAFT FIRE BY SUBMARINES

Lately there appears to be a growing tendency on the part of U-boat commandersto initiate attacks on Allied aircraft, or to counter attack them by machine gun orcannon fire.

Various instances of this character have occurred in the Natal area where U-boatsapparently have been lying in wait for passing aircraft on the east leg of the Natalradio range. On January 16th east of Natal, aircraft from a U.S. Navy carrier de-livered three separate attacks on a fully surfaced submarine. A total of four D/C'swere dropped with no evidence of significant damage resulting. During all threeattacks the U-boat stayed on the surface and fired on the planes.

A PBN3 of Patrol Squadron 74, flying an anti-submarine patrol in the area fromRocas Rock to Fernando de Noronha, sighted a Spanish ship, the "Monte Igueldo", at0940 on February 24th. Shortly thereafter an explosion was seen at the bow of theship. By searching in the direction of the wake of the torpedo, the crew of theplane later discovered the submarine three or four miles off the ships port bowclearly visible about 25 to 35 feet beneath the surface. An attack was made on theU-boat which resulted in possible slight damage.

The report of this action is not clear, but it is stated that the submarine sur-faced and fired on the attacking plane with two machine guns located in the conningtower and both deck guns. These guns, evidently dual purpose, opened up on the air-craft at a range of about one mile and were said to be quite accurate, firing at arapid rate with shells exploding in black and white bursts. After following the tor-pedoed ship, which sank in half an hour, the submarine submerged at 1045 before reliefplanes arrived. Continuous coverage of the area produced no further contact.

The experience of Lt. Cormier and his crew is a B-18B of the 9th AntisubmarineSquadron was described on page 18 of the February issue of this publication. In thiscase the U-boat fired tracer bullets at the landing lights of the plane coming in for


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a night attack. Evasive action was taken by the plane, which lost its radar contactwhen the submarine crash dived. A subsequent attack was made tw o hours later whenthe U-boat resurfaced.

A B-24 on a recent anti-submarine patrol sighted a submarine stationary on thesurface at 1221 about 150 miles south by east of Santa Maria in the Azores. The U-boat fired on the plane. At 1354 a second B-24 arrived on the scene and was alsofired on. The first B-24 attacked at 1430 and 1440 while under fire. The secondplane attacked, also under fire, at 1505. All three attacks were unsuccessful, andthe aircraft departed at 1510. The submarine remained on the surface and headed west.

On March 23, a Coastal Command pilot, while flying a Wellington at an altitudeof 400 feet over the Bay of Biscay sighted a U-boat which opened fire with light can-non. The aircraft was hit between port engine and fuselage. It took evasive actionand the U-boat continued firing until the plane was half a mile distant. The reargunner replied and continued firing at the submarine until his guns jammed. The air-craft then circled th e submarine which again opened fire, this time very inaccurate-ly. The plane attempted to get into position to attack with.depth bombs but theU-boat submerged before the aircraft could make its run.

Damaged submarines, incapable of submerging, have been known to counterattackaircraft by machine gun or anti-aircraft fire. However, if the enemy should gain theimpression that gun fire will keep the would-be attacker at bay until fuel shortageforces him to retire, it is not unlikely that a "stay-and-fight" policy might betried out by U-boat commanders.

Moreover, it is not inconceivable that when a pack engages a convoy, the firstone or two U-boats sighted and attacked by Allied aircraft might be instructed to en-gage ina diversionary anti-aircraft counterattack on th e plane, while other submar-ines in the pack press home the main attack from other angles. In fact, preliminaryreports have been received of antiaircraft fire by some of the submarines during thecourse of a running four-day fight by Coastal Command planes against U-boat packsattempting to converge on two eastbound convoys in March, about 1000 miles west ofLand's End.

For these reasons it ould seem advisable for anti-submarine aircraft crews tobe prepared for such a contingency - not only psychologically, but by predeterminedtechnique developed to meet increasingly audacious tactics of the enemy.

Notwithstanding anti-aircraft fire from the U-boat the bombing attack should bevigorously pressed home as promptly as circumstances permit lest the submarine sub-merge and escape. If enemy personnel are topside, whether or not manning their gunsat the moment, the plane's machine gun fire should be concentrated first against them.In he absence of personnel on deck, the guns should be trained on the hull at thebase of the conning tower, simultaneously with the bombing attack. The accompanyingphotographs of actual attacks illustrate machine gun action against U-boats in theBay of Biscay.

Successful attacks, however, have been made in he face of AA fire. A CoastalCommand Sunderland piloted by F/0 Robertson, sighted a submarine eight miles distant


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while on a sweep West of Ireland.Diving to attack, the aircraft wasmet by fire from the forward gunand the cannon aft. The aircraftpressed home the attack replyingwith front and midships guns anddropped six 250 lb. Torpex depthbombs from a height of thirty feetwhile the U-boat was still sur-faced. Two of these straddled theU-boat just ahead of the conningtower. Air bubbles were seenimmediately after the explosionsubsided and the U-boat's bow pro-jected at an angle above the sur-face and remained so for fiveminutes. It then slid under,stern first, and nothing furtherwas observed.

An excellent attack in theface of U-boat gun fire was madeby F/0 Samuel and his crew in a Fortress of the Coastal Command on March 27, south-east of Iceland. While on anti-submarine sweep at an altitude of 2000 feet the pilotsighted a surfaced submarine three miles distant on the starboard bow. As the planedove to attack approximately 7 to 10 men were seen, some in the conning tower andsome on the deck, and the U-boat opened fire. Six 250-lb. Torpex depth bombs set at25 feet, and spaced at 100 feet were released from a height of 100 feet. One ex-ploded close alongside the U-boat on the starboard quarter; the remainder overshotto port. The tail gunner also fired 200 rounds. The submarine remained visible forabout 15 seconds, then submerged, but the bow reappeared 10 to 15 seconds later at agradually steepening angle.

A second attack was then made, a single 250-lb. Torpex depth charge being re-leased from 50 feet, which was seen to enter the water in foam patch. Tail gunnerwas too busy firing guns to notice explosion of depth charge, but eight to tenseconds after the second attack, he saw the U-boat slide down almost vertically, andobserved a large upheaval of the water followed by air bubbles. At this time he wasactually firing at the underside of U-boat before it disappeared. A minute later, afoam patch was still effervescing and a large quantity of Diesel oil had collectedabout 100 yards across. There was no sign of wreckage or the men that had been seenon the deck.

A brief report has been received of an attack on April 15th by two U.S. Navyplanes near Natal, made under fire from the submarine and resulting in the latter'ssinking. About 50 survivors are said to have been seen in the water, but no furtherdetails of this attack are presently available.


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VIINTERESTING AIRCRAFT ATTACKS

A. TIDEWATER TILLIE TAMES TWO

"Tidewater Tillie" is the B-24PA4JC/ OF CHVLR/D in which 1st Lt. W.L. Sanford and h is. 94TER APPEARED crew of the 2nd Antisubmarine Squadron

:. 4-7AER J[COND RUN. have recently executed two attacks on,BOATAD NVO APP- enemy submarines which resulted in:AR/NT 4Y DUR/i/6 one probably sunk and one known sunk.. .i-.. L THREE ATACS. The first attack, illustrated by

the accompanying diagram, took placeon February 10th about 800 miles westS. of St. Nazaire while the squadron was

..-.::'j.*: operating out of Great Britain. While4 !,:.. " patrolling at 300 feet at the base of

- 2a solid overcast, the left waist230'".-.." gunner sighted a U-boat on the sur-FI'RST ::.. face 10 degrees off the port bow

---SECOD / : about four miles away. A radar con-------- T//RD A' / ... tact had been obtained in the sameJ/B PART14ZY J'OR- position a few seconds before, butFACED DUR/NG F/RST :. . due to sea conditions it had notTWO ATACKST , 'JB/a0[RG- '.. been verified until the visual sight--D /6 JECO/YDS WHFVE/'7V " ".\ 900 ing was made./0,//& /2 ERE DROPPED :200 FFT" HEAD OF - When first observed, the conning

./AS/. tower was clearly seen, bu t as th e.. aircraft approached it disappeared

and about forty feet of the stern wasseen projecting out of the water at an angle of 20 degrees. As the aircraft attackedno churning was visible from the screws of the apparently motionless U-boat. SixMark XI Torpex depth bombs spaced for 19 feet were released from 200 feet at 200 mph.The entire stick overshot; the first depth bomb was observed to explode about 30 feetto starboard of the submarine as the tail gunner fired 75 rounds at the exposed partof the hull.

As the pilot circled to port. the U-boat settled back on an even keel with theconning tower visible and both decks .awash. A second attack on the still motionlesssubmarine was made with three more depth bombs. The tail gunner fired another 75rounds and saw the first depth bomb explode on the port side, while a second explodedto starboard. The U-boat appeared to lift slightly, lurching with the force of theexplosion,, and then remained motionless on the surface.

While Lt. Sanford circled to make a third run the sea was seen to be churnedjust astern of the U-boat, and the conning tower settled beneath the surface without


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way sixteen seconds before the last three depth bombs were released. The detonationsoccurred about 200 feet ahead of the patch of disturbed water, but no plume resulted.Instead, a dome shaped bubble appeared followed by a large circular slick of brownfluid which was described by the crew as definitely not DC residue. Nothing furtherwas seen and thirty minutes later the B-24 set course for base.

Photographs were taken but are too thin to be of any value. When first sightedthe-U-boat apparently was attempting to dive at too steep an angle without sufficientway. This gave the pilot an opportunity to maneuver for two additional attacks whichresulted, according to official Admiralty assessment, in "Probably Sunk".

On March 22, while operating out of a North African base, Lt. Sanford, again inTidewater Tillie, made another attack in the vicinity of the Canary Islands which re-sulted in he complete destruction of the U-boat.

The B-24, camouflaged Mediterranean Blue on its upper surfaces and cloud whiteunderneath, was patrolling at 1200 feet in and out of the base of the cloud coverwhen the co-pilot sighted a broad wake about five miles on the starboard beam. Thepilot continued on his course into the next cloud, then made a 90 degree turn, imme-diately losing altitude. As the plane emerged from the cloud, the wake, still aboutfive miles distant, was observed to be caused by a U-boat proceeding fully surfacedon course 1800. Lt. Sanford decided to continue his run straight ahead and attackfrom the beam with the sun behind him rather than maneuver for a quartering or follow-ing attack. With the aircraft at 200 feet and making about 200 mph, the bombardierreleased four MK XXIX depth bombs spaced at 60 feet, allowing about 1000 feet rangeon the water.

After the drop th e plane continued on its course for eleven seconds to allow theMiller mirror camera to function. The bombs were observed to straddle the U-boat,hitting the water as follows:

#1 - short 130 feet, directly abeam the submarine;#2 - short 70 feet, directly abeam the aft portion of the conning tower;#3 - short 10 feet, directly abeam the aft portion of the conning tower;#4 - long 50 feet.

The explosions enveloped the after portion of the U-boat which continued on itscourse for eleven seconds, then began to settle by th e stern. The entire bow sectionfrom the conning tower forward was projecting out of th e water and in about on e minuteslipped beneath th e surface. Several survivors were observed clinging to debris whichwas strewn about-the area, and a large oil slick developed. Half an hour later, asthe plane was about to depart, a mass of brown, paint-like substance came up in themiddle of the slick. This may have been rusty bilge oil discharged when the U-boatbegan to break up on the bottom.

The accompanying photographs were taken with th e Miller mirror camera and withthe personal camera of the radar operator, who took them upon his own initiative. Thesubmarine was described as painted white with no markings. It ad a streamlined con-ning tower and a very sharp bow. Three men were observed in the conning tower as theplane passed over. One of them tried to man th e anti-aircraft gun.


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U-boat on th e surface after th e plane DC explosion. Bow and conning tower ofpassed over . Spray caused by DC' s U/s visible. U/B is attempting to crashhitting water. Small splash of MfC dive. Large bow wave and spray probablyburst visible forward of conning tower. caused by sudden sideward movement of hull.

Seven survivors clinging to a cylinder like objectand two others (arrow) swimming towards it.


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The attack was evidently a complete surprise and was achieved by a combination ofeffective camouflage, clever use of cloud cover, attacking out of the sun, and accur-ate bombing. Both of Lt. Sanford's attacks attest to the skill and efficiency of thiscrew and to the value of B-24 aircraft in nti-submarine operations. The success ofthese actions was due in part to the long range of the aircraft and its great bombload capacity. More aircraft like Tidewater Tillie, capable of delivering attacks1000 miles off shore with bomb loads of 3000 lbs. or more, promise increasing successagainst th e U-boat.

B. AN ENGLISHMAN CELEBRATES ST. PATRICK'S DAYFlight Officer Esler of th e Coastal Command celebrated St . Patrick's Day by at-

tacking three enemy U-boats and driving down two others which were attempting toshadow a convoy. The entire action occurred within an hour while the Liberator was onconvoy escort over 700 miles from base.

While flying at 3,500 feet, a surfaced U-boat was sighted ten miles away on theport bow. The aircraft dived to attack and, eight seconds after the U-boat's dis-appearance, five 250 lb. Torpex depth bombs, set at 25 feet and spaced at 36 feet,were dropped from a height of 100 feet. The explosions were observed close to theswirl with the center of the stick estimated 80 feet ahead of it. Immediately afterthe explosions th e submarine resurfaced, bows first, then in a few seconds submergedagain. Nothing further was seen.

Thirty minutes later the Liberator had resumed patrol and from 4,000 feet sightedthree U-boats on th e surface. F/C Esler singled out one and attacked up track droppingone depth bomb from a height of 200 feet while th e submarine was still fully surfaced.The explosion was seen at th e stern of the U-boat, which remained on the surface for30-40 seconds apparently unable to dive. The aircraft continued the attack with ma-chine gun fire but no significant results were noted.

Ten minutes later another U-boat was sighted and attacked. Presumably F/0 Eslerhad expended all his depth bombs for this attack was carried ou t with machine gun fireand marine markers. Hits were registered all around th e conning tower and one directhit was made with a marker. A man was seen in he conning tower and is probably acasualty either through machine gun fire or drowning, at th e U-boat submerged directlyafter the attack.

The extent of damage accomplished by F/0 Esler's one-plane show may never beknown, but it is likely that he succeeded in breaking up or at least disorganizing anincipient pack attack on a mid-ocean convoy.

C. RCAF ATTACKS OFF NEWFOUNDLAND

Correction: Under th e title "Convoy Protection off Newfoundland,." on page 16 ofthe February issue of this publication two interesting attacks on U-boats by RoyalCanadian Air Force planes of th e Eastern Air Command were inadvertently referred toas attacks by R.A.F. aircraft.


30/34

UNCLASSILTHE HELICOPTER

Under the guidance of Igor Sikorski - th e helicopter developed in 1942 from ahighly experimental stage to one of "fool proof" performance. Originally designedfor use as an air "flivver", this craft has certain capabilities which may be ofsome importance in anti-submarine operations. The Sikorski-Helicopter has fivefundamental performance-capabilities:

1. Vertical flight - straight up or down.2. Sideways flight - it can cruise with any angle between its long axisand its course - it can fly backwards as easily as forwards.3. Hovering - it can maintain itself at any point in space under itsservice ceiling.4. Rapid and smooth transition between cruising and hovering.5. Safety - th e vertical thrust rotor ca n be shut off, whereupon th ecraft will settle safely to the ground.

On the other hand the helicopter has three principal disadvantages for anti-submarine warfare:

1. Slow speed - maximum speed of current models - 85 mph.2. Limited lifting capacity - present model can carry only 1 pilot and1 DC. Other models are being developed, however, which are expectedto carry a two man crew, special equipment and two or more depthbombs.

3. Limited range - the longest recorded flight to date is ninety-twomiles. Subsequent models are expected to have a range of 300-500 miles.At this date no evaluation of the helicopter as an anti-submarine weapon can bemade. The models now in use are inadequate particularly in load carrying capacity.Projected models, however, are promising enough to have aroused considerable in-terest.

The most hoped for use of these aircraft has been for convoy escor t . Capableof taking off and landing from suitable, cleared deck space, several helicopterscould provide air coverage in mid-ocean areas beyond the normal range of land-based heavy bombers (it is interesting to note, however, that "normal range" isbeing extended so that even mid-ocean areas are now occasionally reached by landbased aircraft). Nevertheless, helicopters equipped with special equipment suchas M.A.D. or sonobuoys, for intance, may be of great value in maintaining contactwith a submerged U-boat. Whether actual attacks can be made or whether this newdevelopment is best suited for scouting or tracking remains to be seen.

Two helicopters will be delivered to Sea Search at Langley for specific anti-submarine experimentation. Tests will be conducted to determine:

1 - weather worthiness2' ability to take off from and land on merchant vessels at sea3 - ability to attack surfaced and submerged U-boats4 - ability to track submerged U-boats5 - ability to evade anti-aircraft fire from U-boats

The results of these tests will determine what functions can be best accom-plished by the helicopter.28

AP7 2:1:'qh F:

ti'y n I


31/34

Technical Details:The unique performance and capabilities of the helicopter are the result of newaeronautical principles. In the case of the airplane and dirigible, the sensitivity

and power of th e rudder control and elevators depends on the forward velocity of thecraft, while in he helicopter, which may move at 80 or 8 or even zero miles per hour,the control is determined by th e tip speed of the rotor blades which are always movingat about 300 miles per hour. The auxiliary rotor at th e tail provides directionalcontrol and torque compensation.

The pitch of the main rotor blades may be increased or decreased at will as theypass any desired point of rotation with a corresponding but opposite variation ofpitch at 180 degrees. The points at which pitch is increased determines whether thehelicopter will fly forwards, sideways, or backwards. Simultaneously increasing ordecreasing pitch on all main rotor blades governs climb and descent. A synchronizingmechanism opens the throttle as pitch is increased, thereby maintaining constant en-gine r.p.m. This pitch control mechanism is actuated by the stick, which acts inflight much like a normal control stick connected to aileron and elevator.

In order to take off, the engine is started with the rotor clutch disengaged andthe rotor brake on. .The brake is then released and with the main pitch control inlow pitch position, tie rotor clutch is engaged. The blades are now turning and are

29


32/34

brought up to the des creased the ship leaves theground and the flight n e failure, a freewheeling deviceis adjusted and the h n d t round.

The current model illustrated in the photograph is powered by a 165 hp. Warnerengine which permits a maximum speed of 80 mph and a gross weight of 2400 lbs. In afuture model it is planned to use an engine with more than double the hp. capable of.lifting almost twice the present load and allowing speeds in excess of 100 mph.

VIII

SUMMARY OF MARCH WEATHER

A. GENERAL CONDITIONS

Weather for March showed no improvement over the weather in February. Flyingweather in general was evenly distributed this month over all areas.

The 25th Wing averaged 78.7%7 contact weather during operating hours, with thearea in the vicinity of Langley Field and Cherry Point obtaining the highest averageof 85%0, with the lowest average of 70% occuring in the Otis, Nitchel and WestoverFields area. Contact weather in the area north of Cape Hatteras averaged 75.1%70,while south of Cape Hatteras it averated 83.3%.

The 26th Wing averaged 90.7% contact weather during operating hours, With Flori-da and Cuba reporting 96.5% and the Gulf area averaging 82.0%.

B. SEVERE THUNDERSTORM HITS JACKSONVILLE, FLORIDAJacksonville experienced a very severe thunderstorm with tornado characteristics

on the morning of March 6th that caused damage to the town and at the Air Base.The thunderstorm with rain, which began at approximately 0730Q, developed into

moderate intensity by 0830Q and steadily increased in intensity so that by 0940Q thewind had attained a velocity estimated at between 85-90 mph at the Air Base. TheJacksonville Naval Air Station recorded a wind velocity of approximately o100 mphbefore power failed. During the early part of the storm, trees were observed to bendwesterly, but later when the storm reached its greatest velocity, buildings felleasterly, in the opposite direction. The barometer made a sudden fall of about 4millibars; this was immediately followed by a sudden rise to a higher level than be-fore the storm.

The path of the storm was mainly from South to North, and observations from theair after the storm showed its track of destruction to vary up to one-half mile inwidth. In the path through the wooded areas, the trees were observed to have fallenhaphazardly and the path indicated skippings which is a characteristic of tornadoes.

The weather maps showed the synoptic situat n not to be unusual, except thatthe tropical maritime air s e m t and convectively unstable:-

30


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conditions necessary for the formation of thunderstorms. The thunderstorm endedabout 1200Q, dtt}2,

C . SUMMARY O ,Ji 1)HThe following table shows the number of days of weather for the first quarter

of 1943 which permitted anti-submarine patrols to be flown by each Wing:% Contact Weather No. Days Patrols FlownJAN. FEB. MAR. JAN. FEB. MAR.

25th AWIG . . . . . . 74.4 78.8 78.7 23.2 25.4 26.126th AWIG ... . .. . 78.5 90.2 90.7 27.8 25.6 28.4

IX

AIR MEDAL AWARDS

Air Medals for "extraordinary achievement while participating in more than200 hours of anti-submarine patrol" have been awarded to 638 officers and enlistedmen of the Antisubmarine Command during recent weeks. Additional awards are to beannounced in the near future.

Three of the 638 men received two Oak Leaf Clusters, the Air Medal havingbeen won twice previously by these men, and eleven were awarded one Oak Leaf clus-ter to Air Medals previously awarded. The directive authorizing award of themedals was issued by General H.H. Arnold, Commanding General of the Army AirForces, and the awards were made by Brigadier General Westside T. Larson, Com-manding General of the Army Air Forces Antisubmarine Command.

The citation with each award reads: "For extraordinary achievement whileparticipating in more than 200 hours of anti-submarine patrol. As members of com-bat crews these individuals displayed outstanding initiative, resourcefulness anda high degree of skill under many trying conditions such as restricted visibility,low ceilings and icing conditions encountered on the large number of flightsnecessary to perform this hazardous patrol of great responsibility.

"Possibility of encountering enemy ships of fighter type or antiaircraft fireadded to the hazards of these missions. The outstanding service of these indivi-duals reflects the highest credit on the military forces of the United States."

Approximately 2,500 American Theater Medals have been awarded to officers andenlisted men participating in patrol duty over water. In lieu of medals, ribbonshave been gven to the winners of the Air Medals and American Theater Medals.Medals wi truck when metal conservation ceases to be necessary.

ei ff1 /_ t


34/34

OMB169 RESEARCH BRAR

2037 Prov.1 ARON2 ARON

WingDet. Serv.

OPERATIONAL

PATROL

485:00

S STICS - MARCH, 1943

ESCORT SPECIAL TRAINING

25th Wing3 ARON. . . . . . .4 ARON. ........5 ARON. . ......6 ARON . . . . . .11 ARON . . . . . .12 ARON . . . . . .13 ARON . . . . . .14 ARON . . . . . .16 ARON . . . . . .19 ARON* . . . . . .20 ARON Det. Serv.22 ARON. ........TOTAL 25th WING. . .

26th Wing7 ARON* . . . . ..8 ARON ......9 ARON In U.S.Det. Serv.10 ARON. . ......15 ARON . . . . . .17 ARON. ........21 ARON . . . . . .23 ARON . . .. . .TOTAL 26th WING.

0. T. U.18 ARON. .......TOTAL AAFAC . ...

CAP,CPESF . . . . . . . .GSF. . . . . . . . .TOTAL CAP,CP .. .

203:40157:55216:35233:3536:40

293:2082:05131:05297:55139:00370:30448:202610:40

17:55446:3513:45910:00116:10281:55398:00446:45769:15

3400:20

221:156717:15

4362:155020:159382:30

217:40150:5516:10

8:0531:153:40

149:504:00

67:15

75:5050:4087:507:4515:3511:15121:0513:15

32:00648:50 413:15

67:0510:5515:00

93:00

741:50

2019:45255:202275:00

21:2072:05

83:35

177:00

94:05684:20

285:25170:35244:50155:20332:05417:25634:05556:50550:15

9:55

259:103615:55

358:30149:2038:45

283:05589:00457:15310:3510:40

2197:10

603:506416:55

114:35114:35 11772:05

*In transit for detached service during part of month.

CLINTON A. BURROWS,Lt. Col., Air Corps, A. C. of S.,- A-2.

TOTAL

485:00

780:35530:05565:25404:45415:35725:40716:10958:50865:25148:55370:30806:45

7288:40

397:45668:0052:30910:00

466:20881:50855:15772:20863:30

5867:30

919:1014560:20

6381:555390:10

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U-Boat Monthly Report - Mar 1943

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