Ass. Comm. Serial No. 137
	Reference:  A.U.D. 792/43.
	Precis of Attack by Liberator Aircraft "D"
	of 311 Squadron.
	Date:  10.11.43. Time:  1345A. Position: 43° 47' N.       07° 52' W.
	Weather Conditions:  Wind 160°, 15 m.p.h.; Weather no cloud; Sea calm; Visibility 15-20 miles.
	Duty:  On A/S patrol.
	Nature of Initial Contact:  "D" was investigating two Spanish M/Vs in position 43° 45' N.  08° 00' W., flying on a track of 130 at 3,000 feet, when an S/E contact was obtained bearing Red 30°, distant 10 miles.
	Aircraft set course to investigate and, two minutes later, sighted a wake and then a U-boat at conning tower depth, bearing Red 30°, distant 8 miles.
	Course and speed of U-boat:  160°, 9-10 knots.
	Direction of Approach:  On approach of aircraft, the U-boat fired a pyrotechnic leaving a double trail of light blue smoke in the air - no coloured stars were observed.  The position of the U-boat was about 3 miles from the shore.
	"D" altered course towards the U-boat, flying in a large circle to port round it in order to confirm its nationality.  The U-boat then opened fire and, taking evasive action, proceeded at full speed to the Spanish Coast.
	A Liberator, E/110, (see serial number 136), was sighted in the vicinity and R/T contact was established.  E/110, who was Titan Leader, asked whether "D" was going to attack' "D" replied that he did intend to attack, but the manoeuvering of the U-boat and the height of the coastline close by, frustrated the first attempt.
	"D" attacked at 1345 from Green 90° to the U-boat's course.
	Details of Attack:  The first pair were fired from 1,000 feet - one failed.  Both of the second pair failed.  The remainder were fired from 600 feet.  R.Ps. were aimed at the conning tower.
	Time of Release:  While U-boat was on the surface.
	Points of Entry :  The R.Ps. entered the water on Green 90°, level with the bows and 50 feet from the U-boat, but were not seen to emerge.
	Surface Evidence:  Fire was experienced from the U-boat from a quadruple cannon abaft the conning tower, shells exploding into blue-grey puffs about 6" in diameter, and from a larger gun or cannon ahead of the conning tower, bursts of black smoke 2-3 feet in diameter.
	No after results of the attack were observed but the U-boat slowed down to 6-8 knots and, when 200 yards from shore, slowed to 2 knots.
	Subsequent Actions of Aircraft:  E/110 informed "D" that he had reached the prudent limit of endurance and was leaving (1352).  "D" remained in the area until 1510, when the prudent limit of endurance having been reached, aircraft set course for base.
	. . . .  When

 

	When last seen the U-boat was proceeding on a North-Westerly course along the Coast within the Rio de Santa Marta Bay at a speed of about 2 knots.
	Description of U-boat:  Only the conning tower was seen, this was camouflaged dark grey and had one long platform abaft on which a quadruple cannon was mounted in a turret-like construction; one large gun was mounted ahead of the conning tower and there was a slight wake ahead of the conning tower, probably caused by a raised stem.  No jumping wires were observed.
	Decision of U-boat Assessment Committee:  From the surface evidence it is considered that the third salvo of R.Ps. damaged the U-boat forward.
	This attack was one of three (Liberators D/311, E/103 and E/110) which so harassed the U-boat as to cause it to abandon ship close to the Spanish Coast.
	The encounter is assessed as "German U-boat known sunk", this aircraft contributing in the proportion of 50%.
	6th December, 1943.