BRIEF OF ATTACK ON ENEMY SUBMARINE
	USS PC-565
	Attack at 1339Q, June 2, 1943.
	Employment:  Escort of NG 365.
	Latitude:  37-43 N; Longitude: 73-16 W
	Weather Conditions:            Clear, Visibility 5 miles, Sea Smooth,
	Wind SSW, Force 3
	Sound Conditions:            Excellent
	Range at which Contact was obtained:            2000 yards.
	Range at which Contact was lost:                      100 yards.
	NARRATIVE
	While patrolling station on the port bow of Convoy NG 365, PC-565 made a sound contact 200 on the port bow range 1600 yards.  Details of depth charge attack that followed are:
	Doppler None H.E.  None Movement of Target Slowly Right Time to Fire obtained by Recorder Width of Target 50 at 2000 yards to 250 at 100 yds. Number of Charges Five Depth Settings  100 feet.
	On turning to reattack, submarine was seen to surface, conning tower awash.  The speed was increased with intention of ramming.  Attempt was made to open fire with all available guns.  No. 1 gun misfired; smoke interference prevented No. 2 gun engaging the target.  Only the starboard 20 mm. gun opened fire – expending 55 rounds and scoring several hits on the conning tower.  When the range closed to about 400 yards, the submarine sank rapidly.  Course was altered to pass about 100 yards ahead of the swirl where one charge set at 100 feet was dropped.  After this second attack contact was not regained.  PC-565 headed for a survivor in the water near the spot the submarine had submerged when an echo was reported 300 yards port bow which was immediately lost.  At the same time (about 7 minutes after the second attack) a large air bubble came to the surface.  Survivor was recovered and search continued.  About 50 minutes after the first attack PC-565 returned to the area and found two large oil slicks.  One of

 

	these was described as being dark with globules of what resembled dark brown oil lacking iridescence.  The second slick was larger and did not appear to be mixed with water.  Oil lay in heavy iridescent patches on the surface.  Samples of floating vegetable fiber and a large piece of flesh (later identified as human flesh) were recovered.  Several splinters of freshly broken wood were seen.  Subsequent search was continued for only two hours.
	Preliminary Report of Interrogation of Survivor.
	Sole survivor stated he was Kapitänleutnant Klaus Bargsten, Commanding Officer of the submarine U-521.  Analysis of the first attack and the testimony of Bargsten indicates the U-521 was completely surprised when attacked.  A short while before the attack the sound operator had reported to Bargsten propeller noises which subsequently faded out.  When the attack occurred Bargsten was in his bunk and the sound of propeller noises overhead were immediately followed by explosions of depth charges.  As a result of this attack instruments were smashed, diving rudders were rendered useless, and all lights extinguished.  The chief engineer apparently lost his head and reported a depth of 150 meters to the Captain.  The Captain gave the order to blow all tanks; the U-521 shot to the surface.  When Bargsten reached the bridge he saw the PC-565 about 200 yards away about to ram.  Considering the situation hopeless he ordered “Abandon Ship”.  The U-521 sank abruptly leaving Bargsten in the water, and with water rushing in the conning tower.
	Surface Evidence of Destruction.
	1.        Surface evidence recovered:  the Commanding Officer and one piece of flesh definitely identified as human flesh.  Samples of vegetable fiber were recovered but ONI has no record of identification.  No samples of the oil or freshly splintered wood were obtained.  Since the piece of human flesh was not recovered until 50 minutes after the initial attack, it is possible it came from one of three sources:
	(a)  As a result of the 20 mm. gunfire;
	(b)  As a result of the single charge explosion dropped in the second attack; or
	(c)  As a result of the crushing of the submarine’s hull on sinking to the bottom.  (Presuming only conning tower hatch was open to the sea).
	(Depth of water, 1200 fathoms.  Pressure – 2682 lbs. per square inch).

 

	2.         If the conning tower only were flooded, there was a possibility that the submarine might still escape by blowing the emergency tanks.  This may have been the source of the large air bubble seen some 7 minutes after the first attack.  However, considering the known damage to the submarine, the fact that wreckage and human flesh were first sighted 50 minutes after the first attack, it seems most unlikely.
	Opinion of Plotting Room:  The U-boat in question had just arrived in the Eastern Sea Frontier at the time of this attack.  No subsequent tracking evidence is available and this room considers the U-521 liquidated in consequence.
	Opinion of Commanding Officer:  Not Stated.
	Opinion of ComEastSeaFron (analyzing authority): Submarine Sunk
	Opinion of Cominch Analytical Section:  Submarine Sunk.
	Decision of Anti-Submarine Assessment Committee: