ANALYSIS OF ANTI-SUBMARINE ACTION BY AIRCRAFT
	Unit:  VP-53                       Unit Report No. 7.
	Airplane Type:  PBY-5.
	Squadron No.:  53-P-1.
	Pilot:  Lt(jg) J.E. Dryden.
	Location of Attack - Latitude:  12-38 N.
	Longitude:  54-49 W.
	Date:  March 8, 1943.
	Time:  1315.  (Zone Plus 4).
	1.        The airplane, using white camouflage, was flying at an altitude of 4500 feet, with the base of occasional cumulus clouds at 1200 to 1500 feet.  Visibility was 15 to 18 miles.  A fully surfaced submarine was visually sighted 8 miles on the port beam.  Because of good visibility conditions, radar was not being used.  Taking good advantage of clouds, the pilot began his approach to attack.  Leaving cloud cover at a range of 1/4 mile at an altitude of 1200 feet, the plane dived to attack at 140 knots.  At an altitude of about 100 feet and with a target angle of 150 degrees, four Mark 44 bombs set for 25 fet were released in salvo, the intervalometer being inoperative.  The submarine was completely surprised.  The plane's gun fire accounted for at least two men on deck.  The port bombs were seen to enter the water just short of target and abaft its conning tower.  The explosion lifted the submarine bodily and caused it to break in the middle.  Both bow and stern rose into the air and then sank below the surface.  Debris, smoke, and water were thrown high into the air.  When the explosion subsided, light and dark oil, considerable wreckage, and eleven men were seen to be on the surface of the water.  Two rubber life rafts and an emergency ration kit were dropped.  One raft failed to inflate because a line attached to the operating lever slipped off as the raft left the plane.  When the plane departed, 99 minutes after the attack, five men were in the other raft, and the remaining six of the eleven first observed had disappeared.
	2.        The approach and attack in this case were excellent, indicating a high degree of training and a good appreciation of the principles of aircraft anti-submarine warfare.  The pilot's performance in this attack and one made by him early in January illustrate what can be done when one is fully aware of the value of cloud cover and proficient in using it to advantage.
	3.        The report of this attack is exceptionally complete and is unusually well prepared.  Recent reports received from this squadron indicate that it is interested not only in sinking submarines but in passing along all information which could possibly be of value to the better prosecution of the anti-submarine campaign.  A fine set of thirteen enlarged photographs was forwarded with the report.
	ENCLOSURE (A) TO
	LANTFLT ASW UNIT
	SERIAL 0233
	DATED

 

	ANALYSIS OF ANTI-SUBMARINE ACTION BY AIRCRAFT
	(Cont'd)
	4.        This report is the first received in which an attack using TORPEX loaded bombs is described.  The effect of that explosive on a submarine is, to say the least, quite interesting.  The comments of the squadron commander are well considered, but his views regarding the relatively greater value of salvo bombing as opposed to the use of a stick of bombs are not concurred in.  The lethal radius of a four bomb salvo theoretically is not quite double that of a single bomb of the same type plus the underwater dispersion between bombs.  That dispersion cannot be predicted with any great amount of accuracy.  After reading analysis of reports of attacks it may be thought that a submarine must be blown to bits before a kill is assessed, but such is not quite the case.  One bomb exploding within "lethal" range is quite sufficient to do "lethal" damage.  It may well be the general feeling among pilots of the squadron that they stand a better chance of a definite kill by using a salvo drop on a fully surfaced submarine.  If that feeling can be substantiated by facts contained from a series of accurately measured drops made under conditions closely simulating actual combat, a basis for further recommendation may be had.  Until then, however, the spacing prescribed in Section B-3, U.S. Fleet Doctrine for Anti-Submarine Warfare by Aircraft should be used.
	5.        It is noted that two large cylinders were reported as part of the debris observed.  This parallels the case of the submarine attacked by a plane of VP-83 on January 6, 1943.  In that attack the submarine appeared to break in two parts, and three large cylinders remained among the floating wreckage.
	6.        The comments made by the Air Operations Officer are of interest and value.  It is apparent that the effort expended in training during the lull in submarine activity is paying dividends.  In this connection it is to be pointed out that all proper training is of immense value, but that only by accurate interpretation of photographic or rake observations or by results of actual attacks is it possible to gauge the true attack efficiency of a combat team or of the unit of which it is a member.
	7.        In view of the observed effect of the attack, the nature and extent of indications remaining on the surface, the appearance of survivors, and the photographic evidence submitted with the report, it is considered that as a result of this attack the submarine was sunk.
	ENCLOSURE (A) TO
	LANTFLT ASW UNIT
	SERIAL 0233
	DATED