28 VW  V  VF  B
        LANGLEY FIELD VIRGINIA  12 JUNE 1615
COMBOMCOM ONE NYC
TWO BG  U  302  E  PERIOD
     
A 1 FORM MIKE SERIAL NO 561    12 JUNE 42
  2 B-17E    2ND GP  LT TUTTLE  A298
  3 1045-1515
     
B 1 GREEN 8  PLANE 1    COVERED AREA FOR RADIUS OF 15 MILES FROM POSITION 395414
  2 1055-1505
     
C 1 PERISCOPE SIGHTED TIME 1150    POSITION 3524 N  7506 W COURSE 200 SPEED 5 KNOTS
  2 VISUAL PICKUP  3 MILES  12 DEGREES LEFT
  3 UNABLE TO DESCRIBE LARGE APPEARING SUB COULD NOT SEE GUNS AS PLANE APPROACHED FROM ASTERN
  4 800 FEET
  6 30 DEGREES DIAGONAL
  7 SIX 325 LB DCs RELEASED
  8 50 FOOT FUSE SETTING    50 FEET SPACING     6 DETONATIONS
  9 200 FEET  175 MPH
  10 10 SECONDS
  11 100 FEET IN FRONT OF SWIRL 50 FOOT SPACINGS ON BOMBS THE THIRD AND FOURTH DC DROPPED STRADDLING THE COURSE OF SS
  12 OIL SLICK ABOUT 150 FEET IN DIAMETER
  13 2 1/2 HOURS THEN RELIEVED
     
F 1 TIME 1400    POSITION 396416
  2 CEILING UNLIMITED VISIBILITY 7 MILES DUE TO HAZE TEMPERATURE P28 AT 1100 FEET WIND NNE AT 15 MPH
  3 SEA MODERATE
  4 FAVORABLE AS IN 2
     
G 1 SUCCESSFUL
  2 200 MILES    S-5    R-5
  5 LAND 20 MILES SHIPS 14 MILES UNABLE TO PICKUP SS
     
T 1610
S COBOMGR TWO
SENT 1625
END ACK PLS
8 5/83 1/2
VF  V  VW  R  NR  28    1625  W
     
     

 

 
 

 
                                                                                                                Langley Field, Virginia,  
                                                                                                                June 12, 1942.  
     
  SUBJECT:  Report on Bombs Dropped.  
     
  TO           :  Commanding Officer, 2nd Bombardment Group (H), Langley Field, Va.  
     
          1.  At 1150 on June 12, 1942, while on patrol mission LY 6 in B-17E No. 19120 at an altitude of 800 feet and on a course of 1830, position 3524N 7506W a large wake was sighted by the co-pilot 200 to the left of us at approximately 2 1/2 miles.  The course of the SS was 2000 speed 5 knots.  We took up a heading to bring us diagonally across the bow and started our bombing run at 200 feet altitude, airspeed of 170 mph laying six 325lb. depth charges at a 300 angle diagonally across the bow of the sub, 50 feet apart, with the mid-point of the six bombs approximately 100 feet ahead of the periscope.  
     
          2.  As we approached the periscope on our run the wake stopped about 4 to 5 seconds before we crossed the course of the periscoope.  All but two members of the cew saw the wake and the engineer observed the first two boils to rise to the surface were white while the 3rd and 4th were black.  We immediately circled and observed a large oil slick approximately 150 feet in diameter, on the side of this slick we dropped two aluminum slicks and circled the area from 1150 until relieved at 1420.  
     
          3.  No further SS indications were sighted.  
     
          4.  Fuze settings on DC's were 25 feet.  
     
                                                                                         
                                                                                         ARTHUR H. TUTTLE, Jr.,  
                                                                                         1st Lieut., Army Air Forces,  
                                                                                         Pilot.  
     
  312.1                                                               1sr Ind.                                                GDD/wjf  
     
  HEADQUARTERS, S-2 Office, 2nd Bomb Gp (H), Langley Field, Va., June 12, 1942.  
 
TO:  Commanding General, 1st Bomber Command, Federal Office Bldg., 90 Church St., New York City, N.Y.
 
 
 
                        Forwarded.  
     
                               For the Group Commander:  
     
 
                                                                                          
 
                                                                                                GEORGE D. DAVIES,  
                                                                                                Captain, Army Air Forces,  
                                                                                                S-2 Officer.  
     
     
 
 
 
 
 
 

 

 
 

                                                          
 
HEADQUARTERS I BOMBER COMMAND
Office of the S-2 Officer
 
90 Church St., New York,
 
 
N.Y.
  
 
 
 
June 14, 1942
 
 
MEMORANDUM :
 
 
 
 
TO                         :  Commanding General, I Bomber Command.
 
 
 
 
                        Analysis of Attacks made by Lt. Tuttle, B-17E, 2nd Bomb Group, at 1150, 12 June 42, position 3524N 7506W.
 
 
 
 
                        This attack was made by a B-17E, 12 June 42.  The U-boat's periscope was sighted three miles away, bearing 3480 from the aircraft, cruising 2000, speed 5.  An attack was made on a course of 3300 relative to U-boat's course, at 200 feet, 175 mph.  Six Mk 17 depth bombs, set for 25 feet, were released in train 50 feet apart, ten seconds after the periscope disappeared.  The mean center of impact of the train of bombs was 100 feet ahead of the periscope wake, on the projected course of the wake.  Am oil slick 150 feet in diameter appeared.
 
 
 
 
                        Analysis:
  
                          Time of flight of bombs from 200 feet-----------------4 sec.  
                          Time of sinking to 25 feet-----------------------------2 sec.  
                          Time of periscope had been out of sight-------------10 sec.  
                          Total time from disappearance to detonation--------16 sec.  
 
 
                          In 16 seconds the U-boat, at full speed (8 knots) moved forward from the visible wake 16 X 13 or 208 feet; at 5 knots the U-boat moved forward 16 X 8.3 or 133 feet.  If the U-boat proceeded at 8 knots the center of impact was 20 feet astern of the pressure hull; if it proceeded at 5 knots, the center of impact was 60 feet forward of the after end of the pressure hull.  
     
                          When cruising at periscope depth the top of the pressure hull was 28 feet below the surface.  In 16 seconds the U-boat submerged and additional 32 feet.  Allowing for the inclination of the U-boat, the point on the top of the pressure hull nearest the points of explosion should have been 50 feet below the surface.  
     
                          In estimating the points of explosions of the bombs the following assumptions have been made regarding the depth bombs:  the forward underwater travel attained before explosion is 50 feet; the depth at which the explosion occurred is assumed to be 32 feet.  
     
 
- 1 -
 
     
 
 
     
     

 

 
 

                                                          
 
     
                          For an 8 knot speed:  No. 2 bomb was 44 feet away; No. 3 was 20 feet away; No. 4 was 36 feet away.  
     
                          For a 5 knot speed:  No. 2 was 21 feet away; no. 3 was 19 feet away; No. 4 was 42 feet away.  
     
 
                        Conclusions:
  
 
 
 
                        At neither assumed speed was there a bomb within lethal raduis.  It is considered probable that the U-boat accelerated to 8 knots at which speed the bombs were astern, and only one close enough to cause damage, hence thia attack is evaluated as resulting in possible damage.
 
 
 
                          Comments:  
     
                          The attack was made promptly, and the pilot-bpmbardier team did well to drop all six depth bombs to compensate for bombing range error.  However, the possible forward travel of the U-boat during the interval between bomb release and explosion was under-estimated.  
     
     
                                                                                                     
                                                                                                             HOWARD MOORE,  
                                                                                                             Lt. Col. AAF,  
                                                                                                             S-2.