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ANALYSIS OF ANTI-SUBMARINE ACTION BY AIRCRAFT |
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| Unit Report Number 19 | |||||||||||||||||||||||||||||
| Airplane Types: 4 TBF's and 4 F4F's. | |||||||||||||||||||||||||||||
| Squadron No: Various | |||||||||||||||||||||||||||||
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| Unit: VC-9 | |||||||||||||||||||||||||||||
| Location of attack: Latitude: 30-49 N. | |||||||||||||||||||||||||||||
| Longitude: 33-49W. | |||||||||||||||||||||||||||||
| Date: 12 June 1943. | |||||||||||||||||||||||||||||
| Time: 1145 (Zone Plus 2). | |||||||||||||||||||||||||||||
| 1. Two planes in company, a TBF and an F4F, were carrying out a regular anti-submarine patrol at 3000 feet, weather clear, no clouds, visibility about 15 miles, sea smooth. Radar was not being used. An enemy submarine fully surfaced and not under way was sighted on the port beam. Distance about one mile. The fighter immediately dove and made a strafing attack, passing over the submarine from astern to bow. The TBF followed immediately behind delivering his attack just as the fighter had finished his strafing run. The TBF strafed with his 30 caliber coming in with lowered wheels to cut down his speed. Four Mark 17-2 depth bombs were dropped in salvo in a shallow dive at 50 feet, speed 180 knots, with fuses set to operate at 25 foot depth, target angle 2250. At the time of release the submarine was in a dive with its conning tower still above water. The bombs were seen to drop in pairs, the explosions straddling the U-boat about amidships. After the explosions the submarine resurfaced at once 900 to the right of its previous heading. It remained with the decks awash, traveling very slowly, trailing oil. At this time an unopposed strafing attack was delivered by the fighter. After traveling about 75 yards the submarine sank to about 25 feet where it could still be seen trailing oil and air bubbles. About this time a second team of one TBF and one fighter arrived on the scene. This second TBF attacked the U-boat just as it resurfaced, dropping four Mark 17-2 depth bombs with the intervalometer set for a spacing of 75 feet, fuses set to function at 25 feet, from an unspecified altitude and speed at a target angle of about 1900. Photographic evidence indicates that the first of these charges hit about 15 feet off the starboard bow of the submarine, remaining charges following along the path of the airplane track. The submarine apparently unharmed by this second attack, stayed on the surface and the second fighter made two strafing attacks, circled and then strafed only when the men from the conning tower tried to man the guns. From here in there were evidently many strafing attacks made by both fighters and both TBF's, singly and together. Gun crews were chased from side to side of the U-boat and all attempts to man the | |||||||||||||||||||||||||||||
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| CONFIDENTIAL | ||
ANALYSIS OF ANTI-SUBMARINE ACTION BY AIRCRAFT |
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(Continued) |
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| guns were frustrated. The next arrival was another TBF which, preceded by a strafing fighter, immediately made an attack from an unspecified altitude, speed, and direction with two Mark 17-2 depth charges with the intervalometer set for 75 foot spacing and fuses set to operate at 25 feet. The explosions were observed to occur on both sides of the conning tower. After the explosions the submarine listed to starboard and appeared to be slowly sinking by the stern. This same TBF attempted to make another run to drop his remaining charges but air traffic was so heavy that he could not make the run. By the time he was able to re-attack it appeared to him unnecessary since the submarine's stern was settling and the crew were jumping over the side. During this time two strafing runs by the second fighter were carried out to clear the decks and keep the gun crews from their guns. After these strafing runs a fourth TBF and an accompanying fighter appeared on the scene. The fighter dove to make a strafing attack immediately followed by the TBF which dropped two Mark 17-2 depth charges in salvo and set to function at a depth of 25 feet, from an unspecified altitude, speed and course. The explosions from the depth charges appeared to be directly underneath the submarine's conning tower. This fourth TBF made a sharp turn and immediately dove to attack with his remaining two depth charges. A simultaneous strafing attack by the 4th fighter was cut short to avoid interference. During this approach the submarine got off its only show of anti-aircraft fire which was very weak. The attack was continued, and the remaining two depth charges, one a Mark 17-2 and one Mark 44, were dropped in salvo with fuses set for 25 feet. This attack was carried out at an unspecified altitude, speed, and course. Explosions from these two depth charges were seen to occur directly under the submarine. At this point the submarine blew up sending large pieces of metal and debris high in the air. At about this time a fifth team of one TBF and one fighter appeared on the scene. There was, however, nothing left to drop on. After the explosion of the submarine many survivors were seen in the water to whom a rubber life raft was thrown. 17 of these were picked up by the U.S.S. OSMOND INGRAM and four dead were left in the water. | ||
| 2. This was certainly a field day for the units involved. Due to the continuous nature of the various attacks and to preserve the continuity this action has been considered as one engagement and comments are submitted on individual attacks as they occurred. The first attack was well coordinated, the TBF following in directly behind the fighter on the first strafing run. Dropping wheels to lower the speed is considered sound. Actions of the submarine subsequent to this first attack, (slow speed, losing oil, and involuntarily resurfacing twice) indicate that the submarine was badly damaged on the first attack. It is felt, however, that dropping in salvo was not justified and that the drop should have more properly been in train. The second attack was carried out in proper | ||
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ANALYSIS OF ANTI-SUBMARINE ACTION BY AIRCRAFT |
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(Continued) |
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| manner, dropping in train. Photographic evidence indicates that the explosions probably occurred outside of the lethal range and ahead. The third attack was very well placed and photographic evidence indicates that the explosions occurred about where they were reported. It is felt, however, that all four charges should have been dropped in view of the other planes that were available. It is considered that this attack very seriously damaged the submarine and would have eventually caused the sinking. The fourth attack was frustrated, probably by the various planes making their concerted strafing attacks. This is the only attack in the series of 6 that was frustrated. It is felt, however, that this attack should have been carried through at the first opportunity inasmuch as the submarine was still afloat and there was no more urgent need for the depth charges. The fifth attack was well coordinated between the fighter and the TBF. The attack itself was excellent and very accurate. However, it is felt that all four bombs should have been dropped in train in view of the ready availability of other planes which were arriving by the minute. The sixth attack, made by this plane was also excellently placed but dropped in salvo instead of in train. It is considered that this last attack was the one which probably set off the explosion in the submarine. With one exception noted, where strafing runs interfered with the paramount business of depth charging, strafing attacks were well made, very accurate, and effectively carried out the mission of keeping the decks cleared of gun crews and rendering anti-aircraft batteries impotent. Photographic evidence indicates the efficacy and accuracy of these attacks. Tactics employed by the strafing planes in working together on opposite sides against exposed personnel and in coordination with the depth charge planes are considered sound. It is desired to comment again on the necessity for the depth charge plane coming in immediately behind the strafing plane so as to give the submarine no time to submerge. |
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| 3. This engagement lasted only about 25 minutes. It involved four depth charge planes and four fighters making a total of five depth charge attacks, one attempted attack and innumerable strafing attacks by fighters. It is felt that coordination of attacks was excellent in that; (a) with but one exception all depth charge attacks were carried out with no delay and were preceded immediately by strafing attacks, (b) the strafing attacks effectively silenced the anti-aircraft batteries so that not a shot was fired until the very last attack and (c) the mission was accomplished with the blowing up of the submarine. This whole group is to be congratulated upon an engagement well and accurately carried out, nicely coordinated and crowned with spectacular success. | ||
4. This report was complete and well prepared except for the omission of dropping data on all but the first depth charge attacks. Of particular interest and value are the excellent set of pictures submitted. These pictures in conjunction with other pictures submitted by this same group would make an excellent folio for training of pilots and intelligence officers. |
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| 5. In view of all the evidence this submarine is considered definitely destroyed. | ||
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